Remove inner abstraction layer from string nodes

## Summary

Part of #7595 

This PR moves the `RUF001` and `RUF002` rules to the AST checker. This
removes the use of docstring detection from these rules.

## Test Plan

As this is just a refactor, make sure existing test cases pass.

.config/nextest.toml

@@ -0,0 +1,8 @@
+[profile.ci]
+# Print out output for failing tests as soon as they fail, and also at the end
+# of the run (for easy scrollability).
+failure-output = "immediate-final"
+# Do not cancel the test run on the first failure.
+fail-fast = false
+
+status-level = "skip"

.github/workflows/ci.yaml

@@ -111,13 +111,23 @@ jobs:
       - uses: actions/checkout@v4
       - name: "Install Rust toolchain"
         run: rustup show
+      - name: "Install mold"
+        uses: rui314/setup-mold@v1
+      - name: "Install cargo nextest"
+        uses: taiki-e/install-action@v2
+        with:
+          tool: cargo-nextest
       - name: "Install cargo insta"
         uses: taiki-e/install-action@v2
         with:
           tool: cargo-insta
       - uses: Swatinem/rust-cache@v2
       - name: "Run tests"
-        run: cargo insta test --all --all-features --unreferenced reject
+        shell: bash
+        env:
+          NEXTEST_PROFILE: "ci"
+        run: cargo insta test --all-features --unreferenced reject --test-runner nextest
+
       # Check for broken links in the documentation.
       - run: cargo doc --all --no-deps
         env:
@@ -138,15 +148,16 @@ jobs:
       - uses: actions/checkout@v4
       - name: "Install Rust toolchain"
         run: rustup show
-      - name: "Install cargo insta"
+      - name: "Install cargo nextest"
         uses: taiki-e/install-action@v2
         with:
-          tool: cargo-insta
+          tool: cargo-nextest
       - uses: Swatinem/rust-cache@v2
       - name: "Run tests"
         shell: bash
-        # We can't reject unreferenced snapshots on windows because flake8_executable can't run on windows
-        run: cargo insta test --all --exclude ruff_dev --all-features
+        run: |
+          cargo nextest run --all-features --profile ci
+          cargo test --all-features --doc
 
   cargo-test-wasm:
     name: "cargo test (wasm)"
@@ -407,7 +418,7 @@ jobs:
       - uses: actions/setup-python@v5
       - name: "Add SSH key"
         if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS == 'true' }}
-        uses: webfactory/ssh-agent@v0.8.0
+        uses: webfactory/ssh-agent@v0.9.0
         with:
           ssh-private-key: ${{ secrets.MKDOCS_INSIDERS_SSH_KEY }}
       - name: "Install Rust toolchain"

.github/workflows/docs.yaml

@@ -23,7 +23,7 @@ jobs:
       - uses: actions/setup-python@v5
       - name: "Add SSH key"
         if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS == 'true' }}
-        uses: webfactory/ssh-agent@v0.8.0
+        uses: webfactory/ssh-agent@v0.9.0
         with:
           ssh-private-key: ${{ secrets.MKDOCS_INSIDERS_SSH_KEY }}
       - name: "Install Rust toolchain"

CHANGELOG.md

@@ -1,5 +1,66 @@
 # Changelog
 
+## 0.2.2
+
+Highlights include:
+
+- Initial support formatting f-strings (in `--preview`).
+- Support for overriding arbitrary configuration options via the CLI through an expanded `--config`
+    argument (e.g., `--config "lint.isort.combine-as-imports=false"`).
+- Significant performance improvements in Ruff's lexer, parser, and lint rules.
+
+### Preview features
+
+- Implement minimal f-string formatting ([#9642](https://github.com/astral-sh/ruff/pull/9642))
+- \[`pycodestyle`\] Add blank line(s) rules (`E301`, `E302`, `E303`, `E304`, `E305`, `E306`) ([#9266](https://github.com/astral-sh/ruff/pull/9266))
+- \[`refurb`\] Implement `readlines_in_for` (`FURB129`) ([#9880](https://github.com/astral-sh/ruff/pull/9880))
+
+### Rule changes
+
+- \[`ruff`\] Ensure closing parentheses for multiline sequences are always on their own line (`RUF022`, `RUF023`) ([#9793](https://github.com/astral-sh/ruff/pull/9793))
+- \[`numpy`\] Add missing deprecation violations (`NPY002`) ([#9862](https://github.com/astral-sh/ruff/pull/9862))
+- \[`flake8-bandit`\] Detect `mark_safe` usages in decorators ([#9887](https://github.com/astral-sh/ruff/pull/9887))
+- \[`ruff`\] Expand `asyncio-dangling-task` (`RUF006`) to include `new_event_loop` ([#9976](https://github.com/astral-sh/ruff/pull/9976))
+- \[`flake8-pyi`\] Ignore 'unused' private type dicts in class scopes ([#9952](https://github.com/astral-sh/ruff/pull/9952))
+
+### Formatter
+
+- Docstring formatting: Preserve tab indentation when using `indent-style=tabs` ([#9915](https://github.com/astral-sh/ruff/pull/9915))
+- Disable top-level docstring formatting for notebooks ([#9957](https://github.com/astral-sh/ruff/pull/9957))
+- Stabilize quote-style's `preserve` mode ([#9922](https://github.com/astral-sh/ruff/pull/9922))
+
+### CLI
+
+- Allow arbitrary configuration options to be overridden via the CLI ([#9599](https://github.com/astral-sh/ruff/pull/9599))
+
+### Bug fixes
+
+- Make `show-settings` filters directory-agnostic ([#9866](https://github.com/astral-sh/ruff/pull/9866))
+- Respect duplicates when rewriting type aliases ([#9905](https://github.com/astral-sh/ruff/pull/9905))
+- Respect tuple assignments in typing analyzer ([#9969](https://github.com/astral-sh/ruff/pull/9969))
+- Use atomic write when persisting cache ([#9981](https://github.com/astral-sh/ruff/pull/9981))
+- Use non-parenthesized range for `DebugText` ([#9953](https://github.com/astral-sh/ruff/pull/9953))
+- \[`flake8-simplify`\] Avoid false positive with `async` for loops (`SIM113`) ([#9996](https://github.com/astral-sh/ruff/pull/9996))
+- \[`flake8-trio`\] Respect `async with` in `timeout-without-await` ([#9859](https://github.com/astral-sh/ruff/pull/9859))
+- \[`perflint`\] Catch a wider range of mutations in `PERF101` ([#9955](https://github.com/astral-sh/ruff/pull/9955))
+- \[`pycodestyle`\] Fix `E30X` panics on blank lines with trailing white spaces ([#9907](https://github.com/astral-sh/ruff/pull/9907))
+- \[`pydocstyle`\] Allow using `parameters` as a subsection header (`D405`) ([#9894](https://github.com/astral-sh/ruff/pull/9894))
+- \[`pydocstyle`\] Fix blank-line docstring rules for module-level docstrings ([#9878](https://github.com/astral-sh/ruff/pull/9878))
+- \[`pylint`\] Accept 0.0 and 1.0 as common magic values (`PLR2004`) ([#9964](https://github.com/astral-sh/ruff/pull/9964))
+- \[`pylint`\] Avoid suggesting set rewrites for non-hashable types ([#9956](https://github.com/astral-sh/ruff/pull/9956))
+- \[`ruff`\] Avoid false negatives with string literals inside of method calls (`RUF027`) ([#9865](https://github.com/astral-sh/ruff/pull/9865))
+- \[`ruff`\] Fix panic on with f-string detection (`RUF027`) ([#9990](https://github.com/astral-sh/ruff/pull/9990))
+- \[`ruff`\] Ignore builtins when detecting missing f-strings ([#9849](https://github.com/astral-sh/ruff/pull/9849))
+
+### Performance
+
+- Use `memchr` for string lexing ([#9888](https://github.com/astral-sh/ruff/pull/9888))
+- Use `memchr` for tab-indentation detection ([#9853](https://github.com/astral-sh/ruff/pull/9853))
+- Reduce `Result<Tok, LexicalError>` size by using `Box<str>` instead of `String` ([#9885](https://github.com/astral-sh/ruff/pull/9885))
+- Reduce size of `Expr` from 80 to 64 bytes ([#9900](https://github.com/astral-sh/ruff/pull/9900))
+- Improve trailing comma rule performance ([#9867](https://github.com/astral-sh/ruff/pull/9867))
+- Remove unnecessary string cloning from the parser ([#9884](https://github.com/astral-sh/ruff/pull/9884))
+
 ## 0.2.1
 
 This release includes support for range formatting (i.e., the ability to format specific lines

CONTRIBUTING.md

@@ -26,6 +26,10 @@ Welcome! We're happy to have you here. Thank you in advance for your contributio
 - [`cargo dev`](#cargo-dev)
 - [Subsystems](#subsystems)
     - [Compilation Pipeline](#compilation-pipeline)
+    - [Import Categorization](#import-categorization)
+        - [Project root](#project-root)
+        - [Package root](#package-root)
+        - [Import categorization](#import-categorization-1)
 
 ## The Basics
 
@@ -35,7 +39,7 @@ For small changes (e.g., bug fixes), feel free to submit a PR.
 
 For larger changes (e.g., new lint rules, new functionality, new configuration options), consider
 creating an [**issue**](https://github.com/astral-sh/ruff/issues) outlining your proposed change.
-You can also join us on [**Discord**](https://discord.gg/c9MhzV8aU5) to discuss your idea with the
+You can also join us on [**Discord**](https://discord.com/invite/astral-sh) to discuss your idea with the
 community. We've labeled [beginner-friendly tasks](https://github.com/astral-sh/ruff/issues?q=is%3Aissue+is%3Aopen+label%3A%22good+first+issue%22)
 in the issue tracker, along with [bugs](https://github.com/astral-sh/ruff/issues?q=is%3Aissue+is%3Aopen+label%3Abug)
 and [improvements](https://github.com/astral-sh/ruff/issues?q=is%3Aissue+is%3Aopen+label%3Aaccepted)
@@ -63,7 +67,7 @@ You'll also need [Insta](https://insta.rs/docs/) to update snapshot tests:
 cargo install cargo-insta
 ```
 
-and pre-commit to run some validation checks:
+And you'll need pre-commit to run some validation checks:
 
 ```shell
 pipx install pre-commit  # or `pip install pre-commit` if you have a virtualenv
@@ -76,6 +80,16 @@ when making a commit:
 pre-commit install
 ```
 
+We recommend [nextest](https://nexte.st/) to run Ruff's test suite (via `cargo nextest run`),
+though it's not strictly necessary:
+
+```shell
+cargo install cargo-nextest --locked
+```
+
+Throughout this guide, any usages of `cargo test` can be replaced with `cargo nextest run`,
+if you choose to install `nextest`.
+
 ### Development
 
 After cloning the repository, run Ruff locally from the repository root with:
@@ -373,6 +387,11 @@ We have several ways of benchmarking and profiling Ruff:
 - Microbenchmarks which run the linter or the formatter on individual files. These run on pull requests.
 - Profiling the linter on either the microbenchmarks or entire projects
 
+> \[!NOTE\]
+> When running benchmarks, ensure that your CPU is otherwise idle (e.g., close any background
+> applications, like web browsers). You may also want to switch your CPU to a "performance"
+> mode, if it exists, especially when benchmarking short-lived processes.
+
 ### CPython Benchmark
 
 First, clone [CPython](https://github.com/python/cpython). It's a large and diverse Python codebase,

Cargo.toml

@@ -19,8 +19,9 @@ argfile = { version = "0.1.6" }
 assert_cmd = { version = "2.0.13" }
 bincode = { version = "1.3.3" }
 bitflags = { version = "2.4.1" }
+bstr = { version = "1.9.0" }
 cachedir = { version = "0.3.1" }
-chrono = { version = "0.4.33", default-features = false, features = ["clock"] }
+chrono = { version = "0.4.34", default-features = false, features = ["clock"] }
 clap = { version = "4.4.18", features = ["derive"] }
 clap_complete_command = { version = "0.5.1" }
 clearscreen = { version = "2.0.0" }
@@ -43,7 +44,7 @@ hexf-parse = { version ="0.2.1"}
 ignore = { version = "0.4.22" }
 imara-diff ={ version = "0.1.5"}
 imperative = { version = "1.0.4" }
-indicatif ={ version = "0.17.7"}
+indicatif ={ version = "0.17.8"}
 indoc ={ version = "2.0.4"}
 insta = { version = "1.34.0", feature = ["filters", "glob"] }
 insta-cmd = { version = "0.4.0" }
@@ -91,7 +92,7 @@ strum_macros = { version = "0.25.3" }
 syn = { version = "2.0.40" }
 tempfile = { version ="3.9.0"}
 test-case = { version = "3.3.1" }
-thiserror = { version = "1.0.51" }
+thiserror = { version = "1.0.57" }
 tikv-jemallocator = { version ="0.5.0"}
 toml = { version = "0.8.9" }
 tracing = { version = "0.1.40" }

README.md

@@ -8,7 +8,7 @@
 [![image](https://img.shields.io/pypi/pyversions/ruff.svg)](https://pypi.python.org/pypi/ruff)
 [![Actions status](https://github.com/astral-sh/ruff/workflows/CI/badge.svg)](https://github.com/astral-sh/ruff/actions)
 
-[**Discord**](https://discord.gg/c9MhzV8aU5) | [**Docs**](https://docs.astral.sh/ruff/) | [**Playground**](https://play.ruff.rs/)
+[**Discord**](https://discord.com/invite/astral-sh) | [**Docs**](https://docs.astral.sh/ruff/) | [**Playground**](https://play.ruff.rs/)
 
 An extremely fast Python linter and code formatter, written in Rust.
 
@@ -150,7 +150,7 @@ Ruff can also be used as a [pre-commit](https://pre-commit.com/) hook via [`ruff
 ```yaml
 - repo: https://github.com/astral-sh/ruff-pre-commit
   # Ruff version.
-  rev: v0.2.1
+  rev: v0.2.2
   hooks:
     # Run the linter.
     - id: ruff
@@ -341,14 +341,14 @@ For a complete enumeration of the supported rules, see [_Rules_](https://docs.as
 Contributions are welcome and highly appreciated. To get started, check out the
 [**contributing guidelines**](https://docs.astral.sh/ruff/contributing/).
 
-You can also join us on [**Discord**](https://discord.gg/c9MhzV8aU5).
+You can also join us on [**Discord**](https://discord.com/invite/astral-sh).
 
 ## Support
 
 Having trouble? Check out the existing issues on [**GitHub**](https://github.com/astral-sh/ruff/issues),
 or feel free to [**open a new one**](https://github.com/astral-sh/ruff/issues/new).
 
-You can also ask for help on [**Discord**](https://discord.gg/c9MhzV8aU5).
+You can also ask for help on [**Discord**](https://discord.com/invite/astral-sh).
 
 ## Acknowledgements
 

crates/ruff/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ruff"
-version = "0.2.1"
+version = "0.2.2"
 publish = false
 authors = { workspace = true }
 edition = { workspace = true }
@@ -48,7 +48,9 @@ serde = { workspace = true }
 serde_json = { workspace = true }
 shellexpand = { workspace = true }
 strum = { workspace = true, features = [] }
+tempfile = { workspace = true }
 thiserror = { workspace = true }
+toml = { workspace = true }
 tracing = { workspace = true, features = ["log"] }
 walkdir = { workspace = true }
 wild = { workspace = true }

crates/ruff/src/args.rs

@@ -1,12 +1,18 @@
 use std::cmp::Ordering;
 use std::fmt::Formatter;
-use std::path::PathBuf;
+use std::ops::Deref;
+use std::path::{Path, PathBuf};
 use std::str::FromStr;
+use std::sync::Arc;
 
+use anyhow::bail;
+use clap::builder::{TypedValueParser, ValueParserFactory};
 use clap::{command, Parser};
 use colored::Colorize;
+use path_absolutize::path_dedot;
 use regex::Regex;
 use rustc_hash::FxHashMap;
+use toml;
 
 use ruff_linter::line_width::LineLength;
 use ruff_linter::logging::LogLevel;
@@ -19,7 +25,7 @@ use ruff_linter::{warn_user, RuleParser, RuleSelector, RuleSelectorParser};
 use ruff_source_file::{LineIndex, OneIndexed};
 use ruff_text_size::TextRange;
 use ruff_workspace::configuration::{Configuration, RuleSelection};
-use ruff_workspace::options::PycodestyleOptions;
+use ruff_workspace::options::{Options, PycodestyleOptions};
 use ruff_workspace::resolver::ConfigurationTransformer;
 
 #[derive(Debug, Parser)]
@@ -155,10 +161,20 @@ pub struct CheckCommand {
     preview: bool,
     #[clap(long, overrides_with("preview"), hide = true)]
     no_preview: bool,
-    /// Path to the `pyproject.toml` or `ruff.toml` file to use for
-    /// configuration.
-    #[arg(long, conflicts_with = "isolated")]
-    pub config: Option<PathBuf>,
+    /// Either a path to a TOML configuration file (`pyproject.toml` or `ruff.toml`),
+    /// or a TOML `<KEY> = <VALUE>` pair
+    /// (such as you might find in a `ruff.toml` configuration file)
+    /// overriding a specific configuration option.
+    /// Overrides of individual settings using this option always take precedence
+    /// over all configuration files, including configuration files that were also
+    /// specified using `--config`.
+    #[arg(
+        long,
+        action = clap::ArgAction::Append,
+        value_name = "CONFIG_OPTION",
+        value_parser = ConfigArgumentParser,
+    )]
+    pub config: Vec<SingleConfigArgument>,
     /// Comma-separated list of rule codes to enable (or ALL, to enable all rules).
     #[arg(
         long,
@@ -291,7 +307,15 @@ pub struct CheckCommand {
     #[arg(short, long, env = "RUFF_NO_CACHE", help_heading = "Miscellaneous")]
     pub no_cache: bool,
     /// Ignore all configuration files.
-    #[arg(long, conflicts_with = "config", help_heading = "Miscellaneous")]
+    //
+    // Note: We can't mark this as conflicting with `--config` here
+    // as `--config` can be used for specifying configuration overrides
+    // as well as configuration files.
+    // Specifying a configuration file conflicts with `--isolated`;
+    // specifying a configuration override does not.
+    // If a user specifies `ruff check --isolated --config=ruff.toml`,
+    // we emit an error later on, after the initial parsing by clap.
+    #[arg(long, help_heading = "Miscellaneous")]
     pub isolated: bool,
     /// Path to the cache directory.
     #[arg(long, env = "RUFF_CACHE_DIR", help_heading = "Miscellaneous")]
@@ -384,9 +408,20 @@ pub struct FormatCommand {
     /// difference between the current file and how the formatted file would look like.
     #[arg(long)]
     pub diff: bool,
-    /// Path to the `pyproject.toml` or `ruff.toml` file to use for configuration.
-    #[arg(long, conflicts_with = "isolated")]
-    pub config: Option<PathBuf>,
+    /// Either a path to a TOML configuration file (`pyproject.toml` or `ruff.toml`),
+    /// or a TOML `<KEY> = <VALUE>` pair
+    /// (such as you might find in a `ruff.toml` configuration file)
+    /// overriding a specific configuration option.
+    /// Overrides of individual settings using this option always take precedence
+    /// over all configuration files, including configuration files that were also
+    /// specified using `--config`.
+    #[arg(
+        long,
+        action = clap::ArgAction::Append,
+        value_name = "CONFIG_OPTION",
+        value_parser = ConfigArgumentParser,
+    )]
+    pub config: Vec<SingleConfigArgument>,
 
     /// Disable cache reads.
     #[arg(short, long, env = "RUFF_NO_CACHE", help_heading = "Miscellaneous")]
@@ -428,7 +463,15 @@ pub struct FormatCommand {
     #[arg(long, help_heading = "Format configuration")]
     pub line_length: Option<LineLength>,
     /// Ignore all configuration files.
-    #[arg(long, conflicts_with = "config", help_heading = "Miscellaneous")]
+    //
+    // Note: We can't mark this as conflicting with `--config` here
+    // as `--config` can be used for specifying configuration overrides
+    // as well as configuration files.
+    // Specifying a configuration file conflicts with `--isolated`;
+    // specifying a configuration override does not.
+    // If a user specifies `ruff check --isolated --config=ruff.toml`,
+    // we emit an error later on, after the initial parsing by clap.
+    #[arg(long, help_heading = "Miscellaneous")]
     pub isolated: bool,
     /// The name of the file when passing it through stdin.
     #[arg(long, help_heading = "Miscellaneous")]
@@ -515,101 +558,181 @@ impl From<&LogLevelArgs> for LogLevel {
     }
 }
 
+/// Configuration-related arguments passed via the CLI.
+#[derive(Default)]
+pub struct ConfigArguments {
+    /// Path to a pyproject.toml or ruff.toml configuration file (etc.).
+    /// Either 0 or 1 configuration file paths may be provided on the command line.
+    config_file: Option<PathBuf>,
+    /// Overrides provided via the `--config "KEY=VALUE"` option.
+    /// An arbitrary number of these overrides may be provided on the command line.
+    /// These overrides take precedence over all configuration files,
+    /// even configuration files that were also specified using `--config`.
+    overrides: Configuration,
+    /// Overrides provided via dedicated flags such as `--line-length` etc.
+    /// These overrides take precedence over all configuration files,
+    /// and also over all overrides specified using any `--config "KEY=VALUE"` flags.
+    per_flag_overrides: ExplicitConfigOverrides,
+}
+
+impl ConfigArguments {
+    pub fn config_file(&self) -> Option<&Path> {
+        self.config_file.as_deref()
+    }
+
+    fn from_cli_arguments(
+        config_options: Vec<SingleConfigArgument>,
+        per_flag_overrides: ExplicitConfigOverrides,
+        isolated: bool,
+    ) -> anyhow::Result<Self> {
+        let mut new = Self {
+            per_flag_overrides,
+            ..Self::default()
+        };
+
+        for option in config_options {
+            match option {
+                SingleConfigArgument::SettingsOverride(overridden_option) => {
+                    let overridden_option = Arc::try_unwrap(overridden_option)
+                        .unwrap_or_else(|option| option.deref().clone());
+                    new.overrides = new.overrides.combine(Configuration::from_options(
+                        overridden_option,
+                        None,
+                        &path_dedot::CWD,
+                    )?);
+                }
+                SingleConfigArgument::FilePath(path) => {
+                    if isolated {
+                        bail!(
+                            "\
+The argument `--config={}` cannot be used with `--isolated`
+
+  tip: You cannot specify a configuration file and also specify `--isolated`,
+       as `--isolated` causes ruff to ignore all configuration files.
+       For more information, try `--help`.
+",
+                            path.display()
+                        );
+                    }
+                    if let Some(ref config_file) = new.config_file {
+                        let (first, second) = (config_file.display(), path.display());
+                        bail!(
+                            "\
+You cannot specify more than one configuration file on the command line.
+
+  tip: remove either `--config={first}` or `--config={second}`.
+       For more information, try `--help`.
+"
+                        );
+                    }
+                    new.config_file = Some(path);
+                }
+            }
+        }
+        Ok(new)
+    }
+}
+
+impl ConfigurationTransformer for ConfigArguments {
+    fn transform(&self, config: Configuration) -> Configuration {
+        let with_config_overrides = self.overrides.clone().combine(config);
+        self.per_flag_overrides.transform(with_config_overrides)
+    }
+}
+
 impl CheckCommand {
     /// Partition the CLI into command-line arguments and configuration
     /// overrides.
-    pub fn partition(self) -> (CheckArguments, CliOverrides) {
-        (
-            CheckArguments {
-                add_noqa: self.add_noqa,
-                config: self.config,
-                diff: self.diff,
-                ecosystem_ci: self.ecosystem_ci,
-                exit_non_zero_on_fix: self.exit_non_zero_on_fix,
-                exit_zero: self.exit_zero,
-                files: self.files,
-                ignore_noqa: self.ignore_noqa,
-                isolated: self.isolated,
-                no_cache: self.no_cache,
-                output_file: self.output_file,
-                show_files: self.show_files,
-                show_settings: self.show_settings,
-                statistics: self.statistics,
-                stdin_filename: self.stdin_filename,
-                watch: self.watch,
-            },
-            CliOverrides {
-                dummy_variable_rgx: self.dummy_variable_rgx,
-                exclude: self.exclude,
-                extend_exclude: self.extend_exclude,
-                extend_fixable: self.extend_fixable,
-                extend_ignore: self.extend_ignore,
-                extend_per_file_ignores: self.extend_per_file_ignores,
-                extend_select: self.extend_select,
-                extend_unfixable: self.extend_unfixable,
-                fixable: self.fixable,
-                ignore: self.ignore,
-                line_length: self.line_length,
-                per_file_ignores: self.per_file_ignores,
-                preview: resolve_bool_arg(self.preview, self.no_preview).map(PreviewMode::from),
-                respect_gitignore: resolve_bool_arg(
-                    self.respect_gitignore,
-                    self.no_respect_gitignore,
-                ),
-                select: self.select,
-                target_version: self.target_version,
-                unfixable: self.unfixable,
-                // TODO(charlie): Included in `pyproject.toml`, but not inherited.
-                cache_dir: self.cache_dir,
-                fix: resolve_bool_arg(self.fix, self.no_fix),
-                fix_only: resolve_bool_arg(self.fix_only, self.no_fix_only),
-                unsafe_fixes: resolve_bool_arg(self.unsafe_fixes, self.no_unsafe_fixes)
-                    .map(UnsafeFixes::from),
-                force_exclude: resolve_bool_arg(self.force_exclude, self.no_force_exclude),
-                output_format: resolve_output_format(
-                    self.output_format,
-                    resolve_bool_arg(self.show_source, self.no_show_source),
-                    resolve_bool_arg(self.preview, self.no_preview).unwrap_or_default(),
-                ),
-                show_fixes: resolve_bool_arg(self.show_fixes, self.no_show_fixes),
-                extension: self.extension,
-            },
-        )
+    pub fn partition(self) -> anyhow::Result<(CheckArguments, ConfigArguments)> {
+        let check_arguments = CheckArguments {
+            add_noqa: self.add_noqa,
+            diff: self.diff,
+            ecosystem_ci: self.ecosystem_ci,
+            exit_non_zero_on_fix: self.exit_non_zero_on_fix,
+            exit_zero: self.exit_zero,
+            files: self.files,
+            ignore_noqa: self.ignore_noqa,
+            isolated: self.isolated,
+            no_cache: self.no_cache,
+            output_file: self.output_file,
+            show_files: self.show_files,
+            show_settings: self.show_settings,
+            statistics: self.statistics,
+            stdin_filename: self.stdin_filename,
+            watch: self.watch,
+        };
+
+        let cli_overrides = ExplicitConfigOverrides {
+            dummy_variable_rgx: self.dummy_variable_rgx,
+            exclude: self.exclude,
+            extend_exclude: self.extend_exclude,
+            extend_fixable: self.extend_fixable,
+            extend_ignore: self.extend_ignore,
+            extend_per_file_ignores: self.extend_per_file_ignores,
+            extend_select: self.extend_select,
+            extend_unfixable: self.extend_unfixable,
+            fixable: self.fixable,
+            ignore: self.ignore,
+            line_length: self.line_length,
+            per_file_ignores: self.per_file_ignores,
+            preview: resolve_bool_arg(self.preview, self.no_preview).map(PreviewMode::from),
+            respect_gitignore: resolve_bool_arg(self.respect_gitignore, self.no_respect_gitignore),
+            select: self.select,
+            target_version: self.target_version,
+            unfixable: self.unfixable,
+            // TODO(charlie): Included in `pyproject.toml`, but not inherited.
+            cache_dir: self.cache_dir,
+            fix: resolve_bool_arg(self.fix, self.no_fix),
+            fix_only: resolve_bool_arg(self.fix_only, self.no_fix_only),
+            unsafe_fixes: resolve_bool_arg(self.unsafe_fixes, self.no_unsafe_fixes)
+                .map(UnsafeFixes::from),
+            force_exclude: resolve_bool_arg(self.force_exclude, self.no_force_exclude),
+            output_format: resolve_output_format(
+                self.output_format,
+                resolve_bool_arg(self.show_source, self.no_show_source),
+                resolve_bool_arg(self.preview, self.no_preview).unwrap_or_default(),
+            ),
+            show_fixes: resolve_bool_arg(self.show_fixes, self.no_show_fixes),
+            extension: self.extension,
+        };
+
+        let config_args =
+            ConfigArguments::from_cli_arguments(self.config, cli_overrides, self.isolated)?;
+        Ok((check_arguments, config_args))
     }
 }
 
 impl FormatCommand {
     /// Partition the CLI into command-line arguments and configuration
     /// overrides.
-    pub fn partition(self) -> (FormatArguments, CliOverrides) {
-        (
-            FormatArguments {
-                check: self.check,
-                diff: self.diff,
-                config: self.config,
-                files: self.files,
-                isolated: self.isolated,
-                no_cache: self.no_cache,
-                stdin_filename: self.stdin_filename,
-                range: self.range,
-            },
-            CliOverrides {
-                line_length: self.line_length,
-                respect_gitignore: resolve_bool_arg(
-                    self.respect_gitignore,
-                    self.no_respect_gitignore,
-                ),
-                exclude: self.exclude,
-                preview: resolve_bool_arg(self.preview, self.no_preview).map(PreviewMode::from),
-                force_exclude: resolve_bool_arg(self.force_exclude, self.no_force_exclude),
-                target_version: self.target_version,
-                cache_dir: self.cache_dir,
-                extension: self.extension,
+    pub fn partition(self) -> anyhow::Result<(FormatArguments, ConfigArguments)> {
+        let format_arguments = FormatArguments {
+            check: self.check,
+            diff: self.diff,
+            files: self.files,
+            isolated: self.isolated,
+            no_cache: self.no_cache,
+            stdin_filename: self.stdin_filename,
+            range: self.range,
+        };
 
-                // Unsupported on the formatter CLI, but required on `Overrides`.
-                ..CliOverrides::default()
-            },
-        )
+        let cli_overrides = ExplicitConfigOverrides {
+            line_length: self.line_length,
+            respect_gitignore: resolve_bool_arg(self.respect_gitignore, self.no_respect_gitignore),
+            exclude: self.exclude,
+            preview: resolve_bool_arg(self.preview, self.no_preview).map(PreviewMode::from),
+            force_exclude: resolve_bool_arg(self.force_exclude, self.no_force_exclude),
+            target_version: self.target_version,
+            cache_dir: self.cache_dir,
+            extension: self.extension,
+
+            // Unsupported on the formatter CLI, but required on `Overrides`.
+            ..ExplicitConfigOverrides::default()
+        };
+
+        let config_args =
+            ConfigArguments::from_cli_arguments(self.config, cli_overrides, self.isolated)?;
+        Ok((format_arguments, config_args))
     }
 }
 
@@ -622,6 +745,154 @@ fn resolve_bool_arg(yes: bool, no: bool) -> Option<bool> {
     }
 }
 
+#[derive(Debug)]
+enum TomlParseFailureKind {
+    SyntaxError,
+    UnknownOption,
+}
+
+impl std::fmt::Display for TomlParseFailureKind {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        let display = match self {
+            Self::SyntaxError => "The supplied argument is not valid TOML",
+            Self::UnknownOption => {
+                "Could not parse the supplied argument as a `ruff.toml` configuration option"
+            }
+        };
+        write!(f, "{display}")
+    }
+}
+
+#[derive(Debug)]
+struct TomlParseFailure {
+    kind: TomlParseFailureKind,
+    underlying_error: toml::de::Error,
+}
+
+impl std::fmt::Display for TomlParseFailure {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        let TomlParseFailure {
+            kind,
+            underlying_error,
+        } = self;
+        let display = format!("{kind}:\n\n{underlying_error}");
+        write!(f, "{}", display.trim_end())
+    }
+}
+
+/// Enumeration to represent a single `--config` argument
+/// passed via the CLI.
+///
+/// Using the `--config` flag, users may pass 0 or 1 paths
+/// to configuration files and an arbitrary number of
+/// "inline TOML" overrides for specific settings.
+///
+/// For example:
+///
+/// ```sh
+/// ruff check --config "path/to/ruff.toml" --config "extend-select=['E501', 'F841']" --config "lint.per-file-ignores = {'some_file.py' = ['F841']}"
+/// ```
+#[derive(Clone, Debug)]
+pub enum SingleConfigArgument {
+    FilePath(PathBuf),
+    SettingsOverride(Arc<Options>),
+}
+
+#[derive(Clone)]
+pub struct ConfigArgumentParser;
+
+impl ValueParserFactory for SingleConfigArgument {
+    type Parser = ConfigArgumentParser;
+
+    fn value_parser() -> Self::Parser {
+        ConfigArgumentParser
+    }
+}
+
+impl TypedValueParser for ConfigArgumentParser {
+    type Value = SingleConfigArgument;
+
+    fn parse_ref(
+        &self,
+        cmd: &clap::Command,
+        arg: Option<&clap::Arg>,
+        value: &std::ffi::OsStr,
+    ) -> Result<Self::Value, clap::Error> {
+        let path_to_config_file = PathBuf::from(value);
+        if path_to_config_file.exists() {
+            return Ok(SingleConfigArgument::FilePath(path_to_config_file));
+        }
+
+        let value = value
+            .to_str()
+            .ok_or_else(|| clap::Error::new(clap::error::ErrorKind::InvalidUtf8))?;
+
+        let toml_parse_error = match toml::Table::from_str(value) {
+            Ok(table) => match table.try_into() {
+                Ok(option) => return Ok(SingleConfigArgument::SettingsOverride(Arc::new(option))),
+                Err(underlying_error) => TomlParseFailure {
+                    kind: TomlParseFailureKind::UnknownOption,
+                    underlying_error,
+                },
+            },
+            Err(underlying_error) => TomlParseFailure {
+                kind: TomlParseFailureKind::SyntaxError,
+                underlying_error,
+            },
+        };
+
+        let mut new_error = clap::Error::new(clap::error::ErrorKind::ValueValidation).with_cmd(cmd);
+        if let Some(arg) = arg {
+            new_error.insert(
+                clap::error::ContextKind::InvalidArg,
+                clap::error::ContextValue::String(arg.to_string()),
+            );
+        }
+        new_error.insert(
+            clap::error::ContextKind::InvalidValue,
+            clap::error::ContextValue::String(value.to_string()),
+        );
+
+        // small hack so that multiline tips
+        // have the same indent on the left-hand side:
+        let tip_indent = " ".repeat("  tip: ".len());
+
+        let mut tip = format!(
+            "\
+A `--config` flag must either be a path to a `.toml` configuration file
+{tip_indent}or a TOML `<KEY> = <VALUE>` pair overriding a specific configuration
+{tip_indent}option"
+        );
+
+        // Here we do some heuristics to try to figure out whether
+        // the user was trying to pass in a path to a configuration file
+        // or some inline TOML.
+        // We want to display the most helpful error to the user as possible.
+        if std::path::Path::new(value)
+            .extension()
+            .map_or(false, |ext| ext.eq_ignore_ascii_case("toml"))
+        {
+            if !value.contains('=') {
+                tip.push_str(&format!(
+                    "
+
+It looks like you were trying to pass a path to a configuration file.
+The path `{value}` does not exist"
+                ));
+            }
+        } else if value.contains('=') {
+            tip.push_str(&format!("\n\n{toml_parse_error}"));
+        }
+
+        new_error.insert(
+            clap::error::ContextKind::Suggested,
+            clap::error::ContextValue::StyledStrs(vec![tip.into()]),
+        );
+
+        Err(new_error)
+    }
+}
+
 fn resolve_output_format(
     output_format: Option<SerializationFormat>,
     show_sources: Option<bool>,
@@ -664,7 +935,6 @@ fn resolve_output_format(
 #[allow(clippy::struct_excessive_bools)]
 pub struct CheckArguments {
     pub add_noqa: bool,
-    pub config: Option<PathBuf>,
     pub diff: bool,
     pub ecosystem_ci: bool,
     pub exit_non_zero_on_fix: bool,
@@ -688,7 +958,6 @@ pub struct FormatArguments {
     pub check: bool,
     pub no_cache: bool,
     pub diff: bool,
-    pub config: Option<PathBuf>,
     pub files: Vec<PathBuf>,
     pub isolated: bool,
     pub stdin_filename: Option<PathBuf>,
@@ -884,39 +1153,40 @@ impl LineColumnParseError {
     }
 }
 
-/// CLI settings that function as configuration overrides.
+/// Configuration overrides provided via dedicated CLI flags:
+/// `--line-length`, `--respect-gitignore`, etc.
 #[derive(Clone, Default)]
 #[allow(clippy::struct_excessive_bools)]
-pub struct CliOverrides {
-    pub dummy_variable_rgx: Option<Regex>,
-    pub exclude: Option<Vec<FilePattern>>,
-    pub extend_exclude: Option<Vec<FilePattern>>,
-    pub extend_fixable: Option<Vec<RuleSelector>>,
-    pub extend_ignore: Option<Vec<RuleSelector>>,
-    pub extend_select: Option<Vec<RuleSelector>>,
-    pub extend_unfixable: Option<Vec<RuleSelector>>,
-    pub fixable: Option<Vec<RuleSelector>>,
-    pub ignore: Option<Vec<RuleSelector>>,
-    pub line_length: Option<LineLength>,
-    pub per_file_ignores: Option<Vec<PatternPrefixPair>>,
-    pub extend_per_file_ignores: Option<Vec<PatternPrefixPair>>,
-    pub preview: Option<PreviewMode>,
-    pub respect_gitignore: Option<bool>,
-    pub select: Option<Vec<RuleSelector>>,
-    pub target_version: Option<PythonVersion>,
-    pub unfixable: Option<Vec<RuleSelector>>,
+struct ExplicitConfigOverrides {
+    dummy_variable_rgx: Option<Regex>,
+    exclude: Option<Vec<FilePattern>>,
+    extend_exclude: Option<Vec<FilePattern>>,
+    extend_fixable: Option<Vec<RuleSelector>>,
+    extend_ignore: Option<Vec<RuleSelector>>,
+    extend_select: Option<Vec<RuleSelector>>,
+    extend_unfixable: Option<Vec<RuleSelector>>,
+    fixable: Option<Vec<RuleSelector>>,
+    ignore: Option<Vec<RuleSelector>>,
+    line_length: Option<LineLength>,
+    per_file_ignores: Option<Vec<PatternPrefixPair>>,
+    extend_per_file_ignores: Option<Vec<PatternPrefixPair>>,
+    preview: Option<PreviewMode>,
+    respect_gitignore: Option<bool>,
+    select: Option<Vec<RuleSelector>>,
+    target_version: Option<PythonVersion>,
+    unfixable: Option<Vec<RuleSelector>>,
     // TODO(charlie): Captured in pyproject.toml as a default, but not part of `Settings`.
-    pub cache_dir: Option<PathBuf>,
-    pub fix: Option<bool>,
-    pub fix_only: Option<bool>,
-    pub unsafe_fixes: Option<UnsafeFixes>,
-    pub force_exclude: Option<bool>,
-    pub output_format: Option<SerializationFormat>,
-    pub show_fixes: Option<bool>,
-    pub extension: Option<Vec<ExtensionPair>>,
+    cache_dir: Option<PathBuf>,
+    fix: Option<bool>,
+    fix_only: Option<bool>,
+    unsafe_fixes: Option<UnsafeFixes>,
+    force_exclude: Option<bool>,
+    output_format: Option<SerializationFormat>,
+    show_fixes: Option<bool>,
+    extension: Option<Vec<ExtensionPair>>,
 }
 
-impl ConfigurationTransformer for CliOverrides {
+impl ConfigurationTransformer for ExplicitConfigOverrides {
     fn transform(&self, mut config: Configuration) -> Configuration {
         if let Some(cache_dir) = &self.cache_dir {
             config.cache_dir = Some(cache_dir.clone());

crates/ruff/src/cache.rs

@@ -1,7 +1,7 @@
 use std::fmt::Debug;
 use std::fs::{self, File};
 use std::hash::Hasher;
-use std::io::{self, BufReader, BufWriter, Write};
+use std::io::{self, BufReader, Write};
 use std::path::{Path, PathBuf};
 use std::sync::atomic::{AtomicU64, Ordering};
 use std::sync::Mutex;
@@ -15,6 +15,7 @@ use rayon::iter::ParallelIterator;
 use rayon::iter::{IntoParallelIterator, ParallelBridge};
 use rustc_hash::FxHashMap;
 use serde::{Deserialize, Serialize};
+use tempfile::NamedTempFile;
 
 use ruff_cache::{CacheKey, CacheKeyHasher};
 use ruff_diagnostics::{DiagnosticKind, Fix};
@@ -165,15 +166,29 @@ impl Cache {
             return Ok(());
         }
 
-        let file = File::create(&self.path)
-            .with_context(|| format!("Failed to create cache file '{}'", self.path.display()))?;
-        let writer = BufWriter::new(file);
-        bincode::serialize_into(writer, &self.package).with_context(|| {
+        // Write the cache to a temporary file first and then rename it for an "atomic" write.
+        // Protects against data loss if the process is killed during the write and races between different ruff
+        // processes, resulting in a corrupted cache file. https://github.com/astral-sh/ruff/issues/8147#issuecomment-1943345964
+        let mut temp_file =
+            NamedTempFile::new_in(self.path.parent().expect("Write path must have a parent"))
+                .context("Failed to create temporary file")?;
+
+        // Serialize to in-memory buffer because hyperfine benchmark showed that it's faster than
+        // using a `BufWriter` and our cache files are small enough that streaming isn't necessary.
+        let serialized =
+            bincode::serialize(&self.package).context("Failed to serialize cache data")?;
+        temp_file
+            .write_all(&serialized)
+            .context("Failed to write serialized cache to temporary file.")?;
+
+        temp_file.persist(&self.path).with_context(|| {
             format!(
-                "Failed to serialise cache to file '{}'",
+                "Failed to rename temporary cache file to {}",
                 self.path.display()
             )
-        })
+        })?;
+
+        Ok(())
     }
 
     /// Applies the pending changes without storing the cache to disk.

crates/ruff/src/commands/add_noqa.rs

@@ -12,17 +12,17 @@ use ruff_linter::warn_user_once;
 use ruff_python_ast::{PySourceType, SourceType};
 use ruff_workspace::resolver::{python_files_in_path, PyprojectConfig, ResolvedFile};
 
-use crate::args::CliOverrides;
+use crate::args::ConfigArguments;
 
 /// Add `noqa` directives to a collection of files.
 pub(crate) fn add_noqa(
     files: &[PathBuf],
     pyproject_config: &PyprojectConfig,
-    overrides: &CliOverrides,
+    config_arguments: &ConfigArguments,
 ) -> Result<usize> {
     // Collect all the files to check.
     let start = Instant::now();
-    let (paths, resolver) = python_files_in_path(files, pyproject_config, overrides)?;
+    let (paths, resolver) = python_files_in_path(files, pyproject_config, config_arguments)?;
     let duration = start.elapsed();
     debug!("Identified files to lint in: {:?}", duration);
 

crates/ruff/src/commands/check.rs

@@ -24,7 +24,7 @@ use ruff_workspace::resolver::{
     match_exclusion, python_files_in_path, PyprojectConfig, ResolvedFile,
 };
 
-use crate::args::CliOverrides;
+use crate::args::ConfigArguments;
 use crate::cache::{Cache, PackageCacheMap, PackageCaches};
 use crate::diagnostics::Diagnostics;
 use crate::panic::catch_unwind;
@@ -34,7 +34,7 @@ use crate::panic::catch_unwind;
 pub(crate) fn check(
     files: &[PathBuf],
     pyproject_config: &PyprojectConfig,
-    overrides: &CliOverrides,
+    config_arguments: &ConfigArguments,
     cache: flags::Cache,
     noqa: flags::Noqa,
     fix_mode: flags::FixMode,
@@ -42,7 +42,7 @@ pub(crate) fn check(
 ) -> Result<Diagnostics> {
     // Collect all the Python files to check.
     let start = Instant::now();
-    let (paths, resolver) = python_files_in_path(files, pyproject_config, overrides)?;
+    let (paths, resolver) = python_files_in_path(files, pyproject_config, config_arguments)?;
     debug!("Identified files to lint in: {:?}", start.elapsed());
 
     if paths.is_empty() {
@@ -233,7 +233,7 @@ mod test {
     use ruff_workspace::resolver::{PyprojectConfig, PyprojectDiscoveryStrategy};
     use ruff_workspace::Settings;
 
-    use crate::args::CliOverrides;
+    use crate::args::ConfigArguments;
 
     use super::check;
 
@@ -272,7 +272,7 @@ mod test {
             // Notebooks are not included by default
             &[tempdir.path().to_path_buf(), notebook],
             &pyproject_config,
-            &CliOverrides::default(),
+            &ConfigArguments::default(),
             flags::Cache::Disabled,
             flags::Noqa::Disabled,
             flags::FixMode::Generate,

crates/ruff/src/commands/check_stdin.rs

@@ -6,7 +6,7 @@ use ruff_linter::packaging;
 use ruff_linter::settings::flags;
 use ruff_workspace::resolver::{match_exclusion, python_file_at_path, PyprojectConfig, Resolver};
 
-use crate::args::CliOverrides;
+use crate::args::ConfigArguments;
 use crate::diagnostics::{lint_stdin, Diagnostics};
 use crate::stdin::{parrot_stdin, read_from_stdin};
 
@@ -14,7 +14,7 @@ use crate::stdin::{parrot_stdin, read_from_stdin};
 pub(crate) fn check_stdin(
     filename: Option<&Path>,
     pyproject_config: &PyprojectConfig,
-    overrides: &CliOverrides,
+    overrides: &ConfigArguments,
     noqa: flags::Noqa,
     fix_mode: flags::FixMode,
 ) -> Result<Diagnostics> {

crates/ruff/src/commands/format.rs

@@ -29,7 +29,7 @@ use ruff_text_size::{TextLen, TextRange, TextSize};
 use ruff_workspace::resolver::{match_exclusion, python_files_in_path, ResolvedFile, Resolver};
 use ruff_workspace::FormatterSettings;
 
-use crate::args::{CliOverrides, FormatArguments, FormatRange};
+use crate::args::{ConfigArguments, FormatArguments, FormatRange};
 use crate::cache::{Cache, FileCacheKey, PackageCacheMap, PackageCaches};
 use crate::panic::{catch_unwind, PanicError};
 use crate::resolve::resolve;
@@ -60,18 +60,17 @@ impl FormatMode {
 /// Format a set of files, and return the exit status.
 pub(crate) fn format(
     cli: FormatArguments,
-    overrides: &CliOverrides,
+    config_arguments: &ConfigArguments,
     log_level: LogLevel,
 ) -> Result<ExitStatus> {
     let pyproject_config = resolve(
         cli.isolated,
-        cli.config.as_deref(),
-        overrides,
+        config_arguments,
         cli.stdin_filename.as_deref(),
     )?;
     let mode = FormatMode::from_cli(&cli);
     let files = resolve_default_files(cli.files, false);
-    let (paths, resolver) = python_files_in_path(&files, &pyproject_config, overrides)?;
+    let (paths, resolver) = python_files_in_path(&files, &pyproject_config, config_arguments)?;
 
     if paths.is_empty() {
         warn_user_once!("No Python files found under the given path(s)");

crates/ruff/src/commands/format_stdin.rs

@@ -9,7 +9,7 @@ use ruff_python_ast::{PySourceType, SourceType};
 use ruff_workspace::resolver::{match_exclusion, python_file_at_path, Resolver};
 use ruff_workspace::FormatterSettings;
 
-use crate::args::{CliOverrides, FormatArguments, FormatRange};
+use crate::args::{ConfigArguments, FormatArguments, FormatRange};
 use crate::commands::format::{
     format_source, warn_incompatible_formatter_settings, FormatCommandError, FormatMode,
     FormatResult, FormattedSource,
@@ -19,11 +19,13 @@ use crate::stdin::{parrot_stdin, read_from_stdin};
 use crate::ExitStatus;
 
 /// Run the formatter over a single file, read from `stdin`.
-pub(crate) fn format_stdin(cli: &FormatArguments, overrides: &CliOverrides) -> Result<ExitStatus> {
+pub(crate) fn format_stdin(
+    cli: &FormatArguments,
+    config_arguments: &ConfigArguments,
+) -> Result<ExitStatus> {
     let pyproject_config = resolve(
         cli.isolated,
-        cli.config.as_deref(),
-        overrides,
+        config_arguments,
         cli.stdin_filename.as_deref(),
     )?;
 
@@ -34,7 +36,7 @@ pub(crate) fn format_stdin(cli: &FormatArguments, overrides: &CliOverrides) -> R
 
     if resolver.force_exclude() {
         if let Some(filename) = cli.stdin_filename.as_deref() {
-            if !python_file_at_path(filename, &mut resolver, overrides)? {
+            if !python_file_at_path(filename, &mut resolver, config_arguments)? {
                 if mode.is_write() {
                     parrot_stdin()?;
                 }

crates/ruff/src/commands/show_files.rs

@@ -7,17 +7,17 @@ use itertools::Itertools;
 use ruff_linter::warn_user_once;
 use ruff_workspace::resolver::{python_files_in_path, PyprojectConfig, ResolvedFile};
 
-use crate::args::CliOverrides;
+use crate::args::ConfigArguments;
 
 /// Show the list of files to be checked based on current settings.
 pub(crate) fn show_files(
     files: &[PathBuf],
     pyproject_config: &PyprojectConfig,
-    overrides: &CliOverrides,
+    config_arguments: &ConfigArguments,
     writer: &mut impl Write,
 ) -> Result<()> {
     // Collect all files in the hierarchy.
-    let (paths, _resolver) = python_files_in_path(files, pyproject_config, overrides)?;
+    let (paths, _resolver) = python_files_in_path(files, pyproject_config, config_arguments)?;
 
     if paths.is_empty() {
         warn_user_once!("No Python files found under the given path(s)");

crates/ruff/src/commands/show_settings.rs

@@ -6,17 +6,17 @@ use itertools::Itertools;
 
 use ruff_workspace::resolver::{python_files_in_path, PyprojectConfig, ResolvedFile};
 
-use crate::args::CliOverrides;
+use crate::args::ConfigArguments;
 
 /// Print the user-facing configuration settings.
 pub(crate) fn show_settings(
     files: &[PathBuf],
     pyproject_config: &PyprojectConfig,
-    overrides: &CliOverrides,
+    config_arguments: &ConfigArguments,
     writer: &mut impl Write,
 ) -> Result<()> {
     // Collect all files in the hierarchy.
-    let (paths, resolver) = python_files_in_path(files, pyproject_config, overrides)?;
+    let (paths, resolver) = python_files_in_path(files, pyproject_config, config_arguments)?;
 
     // Print the list of files.
     let Some(path) = paths

crates/ruff/src/lib.rs

@@ -204,24 +204,23 @@ pub fn run(
 }
 
 fn format(args: FormatCommand, log_level: LogLevel) -> Result<ExitStatus> {
-    let (cli, overrides) = args.partition();
+    let (cli, config_arguments) = args.partition()?;
 
     if is_stdin(&cli.files, cli.stdin_filename.as_deref()) {
-        commands::format_stdin::format_stdin(&cli, &overrides)
+        commands::format_stdin::format_stdin(&cli, &config_arguments)
     } else {
-        commands::format::format(cli, &overrides, log_level)
+        commands::format::format(cli, &config_arguments, log_level)
     }
 }
 
 pub fn check(args: CheckCommand, log_level: LogLevel) -> Result<ExitStatus> {
-    let (cli, overrides) = args.partition();
+    let (cli, config_arguments) = args.partition()?;
 
     // Construct the "default" settings. These are used when no `pyproject.toml`
     // files are present, or files are injected from outside of the hierarchy.
     let pyproject_config = resolve::resolve(
         cli.isolated,
-        cli.config.as_deref(),
-        &overrides,
+        &config_arguments,
         cli.stdin_filename.as_deref(),
     )?;
 
@@ -239,11 +238,21 @@ pub fn check(args: CheckCommand, log_level: LogLevel) -> Result<ExitStatus> {
     let files = resolve_default_files(cli.files, is_stdin);
 
     if cli.show_settings {
-        commands::show_settings::show_settings(&files, &pyproject_config, &overrides, &mut writer)?;
+        commands::show_settings::show_settings(
+            &files,
+            &pyproject_config,
+            &config_arguments,
+            &mut writer,
+        )?;
         return Ok(ExitStatus::Success);
     }
     if cli.show_files {
-        commands::show_files::show_files(&files, &pyproject_config, &overrides, &mut writer)?;
+        commands::show_files::show_files(
+            &files,
+            &pyproject_config,
+            &config_arguments,
+            &mut writer,
+        )?;
         return Ok(ExitStatus::Success);
     }
 
@@ -302,7 +311,8 @@ pub fn check(args: CheckCommand, log_level: LogLevel) -> Result<ExitStatus> {
         if !fix_mode.is_generate() {
             warn_user!("--fix is incompatible with --add-noqa.");
         }
-        let modifications = commands::add_noqa::add_noqa(&files, &pyproject_config, &overrides)?;
+        let modifications =
+            commands::add_noqa::add_noqa(&files, &pyproject_config, &config_arguments)?;
         if modifications > 0 && log_level >= LogLevel::Default {
             let s = if modifications == 1 { "" } else { "s" };
             #[allow(clippy::print_stderr)]
@@ -352,7 +362,7 @@ pub fn check(args: CheckCommand, log_level: LogLevel) -> Result<ExitStatus> {
         let messages = commands::check::check(
             &files,
             &pyproject_config,
-            &overrides,
+            &config_arguments,
             cache.into(),
             noqa.into(),
             fix_mode,
@@ -374,8 +384,7 @@ pub fn check(args: CheckCommand, log_level: LogLevel) -> Result<ExitStatus> {
                     if matches!(change_kind, ChangeKind::Configuration) {
                         pyproject_config = resolve::resolve(
                             cli.isolated,
-                            cli.config.as_deref(),
-                            &overrides,
+                            &config_arguments,
                             cli.stdin_filename.as_deref(),
                         )?;
                     }
@@ -385,7 +394,7 @@ pub fn check(args: CheckCommand, log_level: LogLevel) -> Result<ExitStatus> {
                     let messages = commands::check::check(
                         &files,
                         &pyproject_config,
-                        &overrides,
+                        &config_arguments,
                         cache.into(),
                         noqa.into(),
                         fix_mode,
@@ -402,7 +411,7 @@ pub fn check(args: CheckCommand, log_level: LogLevel) -> Result<ExitStatus> {
             commands::check_stdin::check_stdin(
                 cli.stdin_filename.map(fs::normalize_path).as_deref(),
                 &pyproject_config,
-                &overrides,
+                &config_arguments,
                 noqa.into(),
                 fix_mode,
             )?
@@ -410,7 +419,7 @@ pub fn check(args: CheckCommand, log_level: LogLevel) -> Result<ExitStatus> {
             commands::check::check(
                 &files,
                 &pyproject_config,
-                &overrides,
+                &config_arguments,
                 cache.into(),
                 noqa.into(),
                 fix_mode,

crates/ruff/src/resolve.rs

@@ -11,19 +11,18 @@ use ruff_workspace::resolver::{
     Relativity,
 };
 
-use crate::args::CliOverrides;
+use crate::args::ConfigArguments;
 
 /// Resolve the relevant settings strategy and defaults for the current
 /// invocation.
 pub fn resolve(
     isolated: bool,
-    config: Option<&Path>,
-    overrides: &CliOverrides,
+    config_arguments: &ConfigArguments,
     stdin_filename: Option<&Path>,
 ) -> Result<PyprojectConfig> {
     // First priority: if we're running in isolated mode, use the default settings.
     if isolated {
-        let config = overrides.transform(Configuration::default());
+        let config = config_arguments.transform(Configuration::default());
         let settings = config.into_settings(&path_dedot::CWD)?;
         debug!("Isolated mode, not reading any pyproject.toml");
         return Ok(PyprojectConfig::new(
@@ -36,12 +35,13 @@ pub fn resolve(
     // Second priority: the user specified a `pyproject.toml` file. Use that
     // `pyproject.toml` for _all_ configuration, and resolve paths relative to the
     // current working directory. (This matches ESLint's behavior.)
-    if let Some(pyproject) = config
+    if let Some(pyproject) = config_arguments
+        .config_file()
         .map(|config| config.display().to_string())
         .map(|config| shellexpand::full(&config).map(|config| PathBuf::from(config.as_ref())))
         .transpose()?
     {
-        let settings = resolve_root_settings(&pyproject, Relativity::Cwd, overrides)?;
+        let settings = resolve_root_settings(&pyproject, Relativity::Cwd, config_arguments)?;
         debug!(
             "Using user-specified configuration file at: {}",
             pyproject.display()
@@ -67,7 +67,7 @@ pub fn resolve(
             "Using configuration file (via parent) at: {}",
             pyproject.display()
         );
-        let settings = resolve_root_settings(&pyproject, Relativity::Parent, overrides)?;
+        let settings = resolve_root_settings(&pyproject, Relativity::Parent, config_arguments)?;
         return Ok(PyprojectConfig::new(
             PyprojectDiscoveryStrategy::Hierarchical,
             settings,
@@ -84,7 +84,7 @@ pub fn resolve(
             "Using configuration file (via cwd) at: {}",
             pyproject.display()
         );
-        let settings = resolve_root_settings(&pyproject, Relativity::Cwd, overrides)?;
+        let settings = resolve_root_settings(&pyproject, Relativity::Cwd, config_arguments)?;
         return Ok(PyprojectConfig::new(
             PyprojectDiscoveryStrategy::Hierarchical,
             settings,
@@ -97,7 +97,7 @@ pub fn resolve(
     // "closest" `pyproject.toml` file for every Python file later on, so these act
     // as the "default" settings.)
     debug!("Using Ruff default settings");
-    let config = overrides.transform(Configuration::default());
+    let config = config_arguments.transform(Configuration::default());
     let settings = config.into_settings(&path_dedot::CWD)?;
     Ok(PyprojectConfig::new(
         PyprojectDiscoveryStrategy::Hierarchical,

crates/ruff/tests/format.rs

@@ -90,6 +90,179 @@ fn format_warn_stdin_filename_with_files() {
     "###);
 }
 
+#[test]
+fn nonexistent_config_file() {
+    assert_cmd_snapshot!(Command::new(get_cargo_bin(BIN_NAME))
+        .args(["format", "--config", "foo.toml", "."]), @r###"
+    success: false
+    exit_code: 2
+    ----- stdout -----
+
+    ----- stderr -----
+    error: invalid value 'foo.toml' for '--config <CONFIG_OPTION>'
+
+      tip: A `--config` flag must either be a path to a `.toml` configuration file
+           or a TOML `<KEY> = <VALUE>` pair overriding a specific configuration
+           option
+
+    It looks like you were trying to pass a path to a configuration file.
+    The path `foo.toml` does not exist
+
+    For more information, try '--help'.
+    "###);
+}
+
+#[test]
+fn config_override_rejected_if_invalid_toml() {
+    assert_cmd_snapshot!(Command::new(get_cargo_bin(BIN_NAME))
+        .args(["format", "--config", "foo = bar", "."]), @r###"
+    success: false
+    exit_code: 2
+    ----- stdout -----
+
+    ----- stderr -----
+    error: invalid value 'foo = bar' for '--config <CONFIG_OPTION>'
+
+      tip: A `--config` flag must either be a path to a `.toml` configuration file
+           or a TOML `<KEY> = <VALUE>` pair overriding a specific configuration
+           option
+
+    The supplied argument is not valid TOML:
+
+    TOML parse error at line 1, column 7
+      |
+    1 | foo = bar
+      |       ^
+    invalid string
+    expected `"`, `'`
+
+    For more information, try '--help'.
+    "###);
+}
+
+#[test]
+fn too_many_config_files() -> Result<()> {
+    let tempdir = TempDir::new()?;
+    let ruff_dot_toml = tempdir.path().join("ruff.toml");
+    let ruff2_dot_toml = tempdir.path().join("ruff2.toml");
+    fs::File::create(&ruff_dot_toml)?;
+    fs::File::create(&ruff2_dot_toml)?;
+    let expected_stderr = format!(
+        "\
+ruff failed
+  Cause: You cannot specify more than one configuration file on the command line.
+
+  tip: remove either `--config={}` or `--config={}`.
+       For more information, try `--help`.
+
+",
+        ruff_dot_toml.display(),
+        ruff2_dot_toml.display(),
+    );
+    let cmd = Command::new(get_cargo_bin(BIN_NAME))
+        .arg("format")
+        .arg("--config")
+        .arg(&ruff_dot_toml)
+        .arg("--config")
+        .arg(&ruff2_dot_toml)
+        .arg(".")
+        .output()?;
+    let stderr = std::str::from_utf8(&cmd.stderr)?;
+    assert_eq!(stderr, expected_stderr);
+    Ok(())
+}
+
+#[test]
+fn config_file_and_isolated() -> Result<()> {
+    let tempdir = TempDir::new()?;
+    let ruff_dot_toml = tempdir.path().join("ruff.toml");
+    fs::File::create(&ruff_dot_toml)?;
+    let expected_stderr = format!(
+        "\
+ruff failed
+  Cause: The argument `--config={}` cannot be used with `--isolated`
+
+  tip: You cannot specify a configuration file and also specify `--isolated`,
+       as `--isolated` causes ruff to ignore all configuration files.
+       For more information, try `--help`.
+
+",
+        ruff_dot_toml.display(),
+    );
+    let cmd = Command::new(get_cargo_bin(BIN_NAME))
+        .arg("format")
+        .arg("--config")
+        .arg(&ruff_dot_toml)
+        .arg("--isolated")
+        .arg(".")
+        .output()?;
+    let stderr = std::str::from_utf8(&cmd.stderr)?;
+    assert_eq!(stderr, expected_stderr);
+    Ok(())
+}
+
+#[test]
+fn config_override_via_cli() -> Result<()> {
+    let tempdir = TempDir::new()?;
+    let ruff_toml = tempdir.path().join("ruff.toml");
+    fs::write(&ruff_toml, "line-length = 100")?;
+    let fixture = r#"
+def foo():
+    print("looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong string")
+
+    "#;
+    assert_cmd_snapshot!(Command::new(get_cargo_bin(BIN_NAME))
+        .arg("format")
+        .arg("--config")
+        .arg(&ruff_toml)
+        // This overrides the long line length set in the config file
+        .args(["--config", "line-length=80"])
+        .arg("-")
+        .pass_stdin(fixture), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    def foo():
+        print(
+            "looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong string"
+        )
+
+    ----- stderr -----
+    "###);
+    Ok(())
+}
+
+#[test]
+fn config_doubly_overridden_via_cli() -> Result<()> {
+    let tempdir = TempDir::new()?;
+    let ruff_toml = tempdir.path().join("ruff.toml");
+    fs::write(&ruff_toml, "line-length = 70")?;
+    let fixture = r#"
+def foo():
+    print("looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong string")
+
+    "#;
+    assert_cmd_snapshot!(Command::new(get_cargo_bin(BIN_NAME))
+        .arg("format")
+        .arg("--config")
+        .arg(&ruff_toml)
+        // This overrides the long line length set in the config file...
+        .args(["--config", "line-length=80"])
+        // ...but this overrides them both:
+        .args(["--line-length", "100"])
+        .arg("-")
+        .pass_stdin(fixture), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    def foo():
+        print("looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong string")
+
+    ----- stderr -----
+    "###);
+    Ok(())
+}
+
 #[test]
 fn format_options() -> Result<()> {
     let tempdir = TempDir::new()?;

crates/ruff/tests/lint.rs

@@ -510,6 +510,341 @@ ignore = ["D203", "D212"]
     Ok(())
 }
 
+#[test]
+fn nonexistent_config_file() {
+    assert_cmd_snapshot!(Command::new(get_cargo_bin(BIN_NAME))
+        .args(STDIN_BASE_OPTIONS)
+        .args(["--config", "foo.toml", "."]), @r###"
+    success: false
+    exit_code: 2
+    ----- stdout -----
+
+    ----- stderr -----
+    error: invalid value 'foo.toml' for '--config <CONFIG_OPTION>'
+
+      tip: A `--config` flag must either be a path to a `.toml` configuration file
+           or a TOML `<KEY> = <VALUE>` pair overriding a specific configuration
+           option
+
+    It looks like you were trying to pass a path to a configuration file.
+    The path `foo.toml` does not exist
+
+    For more information, try '--help'.
+    "###);
+}
+
+#[test]
+fn config_override_rejected_if_invalid_toml() {
+    assert_cmd_snapshot!(Command::new(get_cargo_bin(BIN_NAME))
+        .args(STDIN_BASE_OPTIONS)
+        .args(["--config", "foo = bar", "."]), @r###"
+    success: false
+    exit_code: 2
+    ----- stdout -----
+
+    ----- stderr -----
+    error: invalid value 'foo = bar' for '--config <CONFIG_OPTION>'
+
+      tip: A `--config` flag must either be a path to a `.toml` configuration file
+           or a TOML `<KEY> = <VALUE>` pair overriding a specific configuration
+           option
+
+    The supplied argument is not valid TOML:
+
+    TOML parse error at line 1, column 7
+      |
+    1 | foo = bar
+      |       ^
+    invalid string
+    expected `"`, `'`
+
+    For more information, try '--help'.
+    "###);
+}
+
+#[test]
+fn too_many_config_files() -> Result<()> {
+    let tempdir = TempDir::new()?;
+    let ruff_dot_toml = tempdir.path().join("ruff.toml");
+    let ruff2_dot_toml = tempdir.path().join("ruff2.toml");
+    fs::File::create(&ruff_dot_toml)?;
+    fs::File::create(&ruff2_dot_toml)?;
+    insta::with_settings!({
+        filters => vec![(tempdir_filter(&tempdir).as_str(), "[TMP]/")]
+    }, {
+    assert_cmd_snapshot!(Command::new(get_cargo_bin(BIN_NAME))
+        .args(STDIN_BASE_OPTIONS)
+        .arg("--config")
+        .arg(&ruff_dot_toml)
+        .arg("--config")
+        .arg(&ruff2_dot_toml)
+        .arg("."), @r###"
+        success: false
+        exit_code: 2
+        ----- stdout -----
+
+        ----- stderr -----
+        ruff failed
+          Cause: You cannot specify more than one configuration file on the command line.
+
+          tip: remove either `--config=[TMP]/ruff.toml` or `--config=[TMP]/ruff2.toml`.
+               For more information, try `--help`.
+
+        "###);
+    });
+    Ok(())
+}
+
+#[test]
+fn config_file_and_isolated() -> Result<()> {
+    let tempdir = TempDir::new()?;
+    let ruff_dot_toml = tempdir.path().join("ruff.toml");
+    fs::File::create(&ruff_dot_toml)?;
+    insta::with_settings!({
+        filters => vec![(tempdir_filter(&tempdir).as_str(), "[TMP]/")]
+    }, {
+    assert_cmd_snapshot!(Command::new(get_cargo_bin(BIN_NAME))
+        .args(STDIN_BASE_OPTIONS)
+        .arg("--config")
+        .arg(&ruff_dot_toml)
+        .arg("--isolated")
+        .arg("."), @r###"
+        success: false
+        exit_code: 2
+        ----- stdout -----
+
+        ----- stderr -----
+        ruff failed
+          Cause: The argument `--config=[TMP]/ruff.toml` cannot be used with `--isolated`
+
+          tip: You cannot specify a configuration file and also specify `--isolated`,
+               as `--isolated` causes ruff to ignore all configuration files.
+               For more information, try `--help`.
+
+        "###);
+    });
+    Ok(())
+}
+
+#[test]
+fn config_override_via_cli() -> Result<()> {
+    let tempdir = TempDir::new()?;
+    let ruff_toml = tempdir.path().join("ruff.toml");
+    fs::write(
+        &ruff_toml,
+        r#"
+line-length = 100
+
+[lint]
+select = ["I"]
+
+[lint.isort]
+combine-as-imports = true
+        "#,
+    )?;
+    let fixture = r#"
+from foo import (
+    aaaaaaaaaaaaaaaaaaa,
+    bbbbbbbbbbb as bbbbbbbbbbbbbbbb,
+    cccccccccccccccc,
+    ddddddddddd as ddddddddddddd,
+    eeeeeeeeeeeeeee,
+    ffffffffffff as ffffffffffffff,
+    ggggggggggggg,
+    hhhhhhh as hhhhhhhhhhh,
+    iiiiiiiiiiiiii,
+    jjjjjjjjjjjjj as jjjjjj,
+)
+
+x = "longer_than_90_charactersssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss"
+"#;
+    assert_cmd_snapshot!(Command::new(get_cargo_bin(BIN_NAME))
+        .args(STDIN_BASE_OPTIONS)
+        .arg("--config")
+        .arg(&ruff_toml)
+        .args(["--config", "line-length=90"])
+        .args(["--config", "lint.extend-select=['E501', 'F841']"])
+        .args(["--config", "lint.isort.combine-as-imports = false"])
+        .arg("-")
+        .pass_stdin(fixture), @r###"
+    success: false
+    exit_code: 1
+    ----- stdout -----
+    -:2:1: I001 [*] Import block is un-sorted or un-formatted
+    -:15:91: E501 Line too long (97 > 90)
+    Found 2 errors.
+    [*] 1 fixable with the `--fix` option.
+
+    ----- stderr -----
+    "###);
+    Ok(())
+}
+
+#[test]
+fn valid_toml_but_nonexistent_option_provided_via_config_argument() {
+    assert_cmd_snapshot!(Command::new(get_cargo_bin(BIN_NAME))
+        .args(STDIN_BASE_OPTIONS)
+        .args([".", "--config", "extend-select=['F481']"]),  // No such code as F481!
+        @r###"
+    success: false
+    exit_code: 2
+    ----- stdout -----
+
+    ----- stderr -----
+    error: invalid value 'extend-select=['F481']' for '--config <CONFIG_OPTION>'
+
+      tip: A `--config` flag must either be a path to a `.toml` configuration file
+           or a TOML `<KEY> = <VALUE>` pair overriding a specific configuration
+           option
+
+    Could not parse the supplied argument as a `ruff.toml` configuration option:
+
+    Unknown rule selector: `F481`
+
+    For more information, try '--help'.
+    "###);
+}
+
+#[test]
+fn each_toml_option_requires_a_new_flag_1() {
+    assert_cmd_snapshot!(Command::new(get_cargo_bin(BIN_NAME))
+        .args(STDIN_BASE_OPTIONS)
+        // commas can't be used to delimit different config overrides;
+        // you need a new --config flag for each override
+        .args([".", "--config", "extend-select=['F841'], line-length=90"]),
+        @r###"
+    success: false
+    exit_code: 2
+    ----- stdout -----
+
+    ----- stderr -----
+    error: invalid value 'extend-select=['F841'], line-length=90' for '--config <CONFIG_OPTION>'
+
+      tip: A `--config` flag must either be a path to a `.toml` configuration file
+           or a TOML `<KEY> = <VALUE>` pair overriding a specific configuration
+           option
+
+    The supplied argument is not valid TOML:
+
+    TOML parse error at line 1, column 23
+      |
+    1 | extend-select=['F841'], line-length=90
+      |                       ^
+    expected newline, `#`
+
+    For more information, try '--help'.
+    "###);
+}
+
+#[test]
+fn each_toml_option_requires_a_new_flag_2() {
+    assert_cmd_snapshot!(Command::new(get_cargo_bin(BIN_NAME))
+        .args(STDIN_BASE_OPTIONS)
+        // spaces *also* can't be used to delimit different config overrides;
+        // you need a new --config flag for each override
+        .args([".", "--config", "extend-select=['F841'] line-length=90"]),
+        @r###"
+    success: false
+    exit_code: 2
+    ----- stdout -----
+
+    ----- stderr -----
+    error: invalid value 'extend-select=['F841'] line-length=90' for '--config <CONFIG_OPTION>'
+
+      tip: A `--config` flag must either be a path to a `.toml` configuration file
+           or a TOML `<KEY> = <VALUE>` pair overriding a specific configuration
+           option
+
+    The supplied argument is not valid TOML:
+
+    TOML parse error at line 1, column 24
+      |
+    1 | extend-select=['F841'] line-length=90
+      |                        ^
+    expected newline, `#`
+
+    For more information, try '--help'.
+    "###);
+}
+
+#[test]
+fn config_doubly_overridden_via_cli() -> Result<()> {
+    let tempdir = TempDir::new()?;
+    let ruff_toml = tempdir.path().join("ruff.toml");
+    fs::write(
+        &ruff_toml,
+        r#"
+line-length = 100
+
+[lint]
+select=["E501"]
+"#,
+    )?;
+    let fixture = "x = 'longer_than_90_charactersssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss'";
+    assert_cmd_snapshot!(Command::new(get_cargo_bin(BIN_NAME))
+        .args(STDIN_BASE_OPTIONS)
+        // The --line-length flag takes priority over both the config file
+        // and the `--config="line-length=110"` flag,
+        // despite them both being specified after this flag on the command line:
+        .args(["--line-length", "90"])
+        .arg("--config")
+        .arg(&ruff_toml)
+        .args(["--config", "line-length=110"])
+        .arg("-")
+        .pass_stdin(fixture), @r###"
+    success: false
+    exit_code: 1
+    ----- stdout -----
+    -:1:91: E501 Line too long (97 > 90)
+    Found 1 error.
+
+    ----- stderr -----
+    "###);
+    Ok(())
+}
+
+#[test]
+fn complex_config_setting_overridden_via_cli() -> Result<()> {
+    let tempdir = TempDir::new()?;
+    let ruff_toml = tempdir.path().join("ruff.toml");
+    fs::write(&ruff_toml, "lint.select = ['N801']")?;
+    let fixture = "class violates_n801: pass";
+    assert_cmd_snapshot!(Command::new(get_cargo_bin(BIN_NAME))
+        .args(STDIN_BASE_OPTIONS)
+        .arg("--config")
+        .arg(&ruff_toml)
+        .args(["--config", "lint.per-file-ignores = {'generated.py' = ['N801']}"])
+        .args(["--stdin-filename", "generated.py"])
+        .arg("-")
+        .pass_stdin(fixture), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    "###);
+    Ok(())
+}
+
+#[test]
+fn deprecated_config_option_overridden_via_cli() {
+    assert_cmd_snapshot!(Command::new(get_cargo_bin(BIN_NAME))
+        .args(STDIN_BASE_OPTIONS)
+        .args(["--config", "select=['N801']", "-"])
+        .pass_stdin("class lowercase: ..."),
+        @r###"
+    success: false
+    exit_code: 1
+    ----- stdout -----
+    -:1:7: N801 Class name `lowercase` should use CapWords convention 
+    Found 1 error.
+
+    ----- stderr -----
+    warning: The top-level linter settings are deprecated in favour of their counterparts in the `lint` section. Please update the following options in your `--config` CLI arguments:
+      - 'select' -> 'lint.select'
+    "###);
+}
+
 #[test]
 fn extension() -> Result<()> {
     let tempdir = TempDir::new()?;

crates/ruff/tests/snapshots/integration_test__explain_status_codes_f401.snap

@@ -25,6 +25,15 @@ import cycles. They also increase the cognitive load of reading the code.
 If an import statement is used to check for the availability or existence
 of a module, consider using `importlib.util.find_spec` instead.
 
+If an import statement is used to re-export a symbol as part of a module's
+public interface, consider using a "redundant" import alias, which
+instructs Ruff (and other tools) to respect the re-export, and avoid
+marking it as unused, as in:
+
+```python
+from module import member as member
+```
+
 ## Example
 ```python
 import numpy as np  # unused import
@@ -51,11 +60,12 @@ else:
 ```
 
 ## Options
-- `lint.pyflakes.extend-generics`
+- `lint.ignore-init-module-imports`
 
 ## References
 - [Python documentation: `import`](https://docs.python.org/3/reference/simple_stmts.html#the-import-statement)
 - [Python documentation: `importlib.util.find_spec`](https://docs.python.org/3/library/importlib.html#importlib.util.find_spec)
+- [Typing documentation: interface conventions](https://typing.readthedocs.io/en/latest/source/libraries.html#library-interface-public-and-private-symbols)
 
 ----- stderr -----
 

crates/ruff_benchmark/Cargo.toml

@@ -13,6 +13,7 @@ license = { workspace = true }
 
 [lib]
 bench = false
+doctest = false
 
 [[bench]]
 name = "linter"

crates/ruff_dev/src/format_dev.rs

@@ -27,7 +27,7 @@ use tracing_subscriber::layer::SubscriberExt;
 use tracing_subscriber::util::SubscriberInitExt;
 use tracing_subscriber::EnvFilter;
 
-use ruff::args::{CliOverrides, FormatArguments, FormatCommand, LogLevelArgs};
+use ruff::args::{ConfigArguments, FormatArguments, FormatCommand, LogLevelArgs};
 use ruff::resolve::resolve;
 use ruff_formatter::{FormatError, LineWidth, PrintError};
 use ruff_linter::logging::LogLevel;
@@ -38,24 +38,23 @@ use ruff_python_formatter::{
 use ruff_python_parser::ParseError;
 use ruff_workspace::resolver::{python_files_in_path, PyprojectConfig, ResolvedFile, Resolver};
 
-fn parse_cli(dirs: &[PathBuf]) -> anyhow::Result<(FormatArguments, CliOverrides)> {
+fn parse_cli(dirs: &[PathBuf]) -> anyhow::Result<(FormatArguments, ConfigArguments)> {
     let args_matches = FormatCommand::command()
         .no_binary_name(true)
         .get_matches_from(dirs);
     let arguments: FormatCommand = FormatCommand::from_arg_matches(&args_matches)?;
-    let (cli, overrides) = arguments.partition();
-    Ok((cli, overrides))
+    let (cli, config_arguments) = arguments.partition()?;
+    Ok((cli, config_arguments))
 }
 
 /// Find the [`PyprojectConfig`] to use for formatting.
 fn find_pyproject_config(
     cli: &FormatArguments,
-    overrides: &CliOverrides,
+    config_arguments: &ConfigArguments,
 ) -> anyhow::Result<PyprojectConfig> {
     let mut pyproject_config = resolve(
         cli.isolated,
-        cli.config.as_deref(),
-        overrides,
+        config_arguments,
         cli.stdin_filename.as_deref(),
     )?;
     // We don't want to format pyproject.toml
@@ -72,9 +71,9 @@ fn find_pyproject_config(
 fn ruff_check_paths<'a>(
     pyproject_config: &'a PyprojectConfig,
     cli: &FormatArguments,
-    overrides: &CliOverrides,
+    config_arguments: &ConfigArguments,
 ) -> anyhow::Result<(Vec<Result<ResolvedFile, ignore::Error>>, Resolver<'a>)> {
-    let (paths, resolver) = python_files_in_path(&cli.files, pyproject_config, overrides)?;
+    let (paths, resolver) = python_files_in_path(&cli.files, pyproject_config, config_arguments)?;
     Ok((paths, resolver))
 }
 

crates/ruff_diagnostics/Cargo.toml

@@ -11,6 +11,7 @@ repository = { workspace = true }
 license = { workspace = true }
 
 [lib]
+doctest = false
 
 [dependencies]
 ruff_text_size = { path = "../ruff_text_size" }

crates/ruff_index/Cargo.toml

@@ -11,6 +11,7 @@ repository = { workspace = true }
 license = { workspace = true }
 
 [lib]
+doctest = false
 
 [dependencies]
 ruff_macros = { path = "../ruff_macros" }

crates/ruff_linter/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ruff_linter"
-version = "0.2.1"
+version = "0.2.2"
 publish = false
 authors = { workspace = true }
 edition = { workspace = true }

crates/ruff_linter/resources/test/fixtures/flake8_pyi/PYI049.py

@@ -11,13 +11,25 @@ class _UnusedTypedDict2(typing.TypedDict):
 
 
 class _UsedTypedDict(TypedDict):
-   foo: bytes
+    foo: bytes
 
 
 class _CustomClass(_UsedTypedDict):
     bar: list[int]
 
+
 _UnusedTypedDict3 = TypedDict("_UnusedTypedDict3", {"foo": int})
 _UsedTypedDict3 = TypedDict("_UsedTypedDict3", {"bar": bytes})
 
+
 def uses_UsedTypedDict3(arg: _UsedTypedDict3) -> None: ...
+
+
+# In `.py` files, we don't flag unused definitions in class scopes (unlike in `.pyi`
+# files).
+class _CustomClass3:
+    class _UnusedTypeDict4(TypedDict):
+        pass
+
+    def method(self) -> None:
+        _CustomClass3._UnusedTypeDict4()

crates/ruff_linter/resources/test/fixtures/flake8_pyi/PYI049.pyi

@@ -35,3 +35,13 @@ _UnusedTypedDict3 = TypedDict("_UnusedTypedDict3", {"foo": int})
 _UsedTypedDict3 = TypedDict("_UsedTypedDict3", {"bar": bytes})
 
 def uses_UsedTypedDict3(arg: _UsedTypedDict3) -> None: ...
+
+
+# In `.pyi` files, we flag unused definitions in class scopes as well as in the global
+# scope (unlike in `.py` files).
+class _CustomClass3:
+    class _UnusedTypeDict4(TypedDict):
+        pass
+
+    def method(self) -> None:
+        _CustomClass3._UnusedTypeDict4()

crates/ruff_linter/resources/test/fixtures/flake8_simplify/SIM113.py

@@ -193,3 +193,11 @@ def func():
         for y in range(5):
             g(x, idx)
             idx += 1
+
+async def func():
+    # OK (for loop is async)
+    idx = 0
+
+    async for x in async_gen():
+        g(x, idx)
+        idx += 1

crates/ruff_linter/resources/test/fixtures/perflint/PERF101.py

@@ -36,35 +36,47 @@ for i in list( # Comment
 ):  # PERF101
     pass
 
-for i in list(foo_dict):  # Ok
+for i in list(foo_dict):  # OK
     pass
 
-for i in list(1):  # Ok
+for i in list(1):  # OK
     pass
 
-for i in list(foo_int):  # Ok
+for i in list(foo_int):  # OK
     pass
 
 
 import itertools
 
-for i in itertools.product(foo_int):  # Ok
+for i in itertools.product(foo_int):  # OK
     pass
 
-for i in list(foo_list):  # Ok
+for i in list(foo_list):  # OK
     foo_list.append(i + 1)
 
 for i in list(foo_list):  # PERF101
     # Make sure we match the correct list
     other_list.append(i + 1)
 
-for i in list(foo_tuple):  # Ok
+for i in list(foo_tuple):  # OK
     foo_tuple.append(i + 1)
 
-for i in list(foo_set):  # Ok
+for i in list(foo_set):  # OK
     foo_set.append(i + 1)
 
 x, y, nested_tuple = (1, 2, (3, 4, 5))
 
 for i in list(nested_tuple):  # PERF101
     pass
+
+for i in list(foo_list):  # OK
+    if True:
+        foo_list.append(i + 1)
+
+for i in list(foo_list):  # OK
+    if True:
+        foo_list[i] = i + 1
+
+for i in list(foo_list):  # OK
+    if True:
+        del foo_list[i + 1]

crates/ruff_linter/resources/test/fixtures/pylint/literal_membership.py

@@ -4,7 +4,12 @@
 1 in (
     1, 2, 3
 )
-
-# OK
 fruits = ["cherry", "grapes"]
 "cherry" in fruits
+_ = {key: value for key, value in {"a": 1, "b": 2}.items() if key in ("a", "b")}
+
+# OK
+fruits in [[1, 2, 3], [4, 5, 6]]
+fruits in [1, 2, 3]
+1 in [[1, 2, 3], [4, 5, 6]]
+_ = {key: value for key, value in {"a": 1, "b": 2}.items() if key in (["a", "b"], ["c", "d"])}

crates/ruff_linter/resources/test/fixtures/pylint/magic_value_comparison.py

@@ -35,6 +35,15 @@ if argc != 0:  # correct
 if argc != 1:  # correct
     pass
 
+if argc != -1.0:  # correct
+    pass
+
+if argc != 0.0:  # correct
+    pass
+
+if argc != 1.0:  # correct
+    pass
+
 if argc != 2:  # [magic-value-comparison]
     pass
 
@@ -44,6 +53,12 @@ if argc != -2:  # [magic-value-comparison]
 if argc != +2:  # [magic-value-comparison]
     pass
 
+if argc != -2.0:  # [magic-value-comparison]
+    pass
+
+if argc != +2.0:  # [magic-value-comparison]
+    pass
+
 if __name__ == "__main__":  # correct
     pass
 

crates/ruff_linter/resources/test/fixtures/refurb/FURB129.py

@@ -0,0 +1,75 @@
+import codecs
+import io
+from pathlib import Path
+
+# Errors
+with open("FURB129.py") as f:
+    for _line in f.readlines():
+        pass
+    a = [line.lower() for line in f.readlines()]
+    b = {line.upper() for line in f.readlines()}
+    c = {line.lower(): line.upper() for line in f.readlines()}
+
+with Path("FURB129.py").open() as f:
+    for _line in f.readlines():
+        pass
+
+for _line in open("FURB129.py").readlines():
+    pass
+
+for _line in Path("FURB129.py").open().readlines():
+    pass
+
+
+def func():
+    f = Path("FURB129.py").open()
+    for _line in f.readlines():
+        pass
+    f.close()
+
+
+def func(f: io.BytesIO):
+    for _line in f.readlines():
+        pass
+
+
+def func():
+    with (open("FURB129.py") as f, foo as bar):
+        for _line in f.readlines():
+            pass
+        for _line in bar.readlines():
+            pass
+
+
+# False positives
+def func(f):
+    for _line in f.readlines():
+        pass
+
+
+def func(f: codecs.StreamReader):
+    for _line in f.readlines():
+        pass
+
+
+def func():
+    class A:
+        def readlines(self) -> list[str]:
+            return ["a", "b", "c"]
+
+    return A()
+
+
+for _line in func().readlines():
+    pass
+
+# OK
+for _line in ["a", "b", "c"]:
+    pass
+with open("FURB129.py") as f:
+    for _line in f:
+        pass
+    for _line in f.readlines(10):
+        pass
+    for _not_line in f.readline():
+        pass

crates/ruff_linter/resources/test/fixtures/ruff/RUF006.py

@@ -162,3 +162,26 @@ async def f(x: bool):
         T = asyncio.create_task(asyncio.sleep(1))
     else:
         T = None
+
+
+# Error
+def f():
+    loop = asyncio.new_event_loop()
+    loop.create_task(main()) # Error
+
+# Error
+def f():
+    loop = asyncio.get_event_loop()
+    loop.create_task(main()) # Error
+
+# OK
+def f():
+    global task
+    loop = asyncio.new_event_loop()
+    task = loop.create_task(main()) # Error
+
+# OK
+def f():
+    global task
+    loop = asyncio.get_event_loop()
+    task = loop.create_task(main()) # Error

crates/ruff_linter/resources/test/fixtures/ruff/RUF022.py

@@ -250,6 +250,23 @@ __all__ = (
     ,
 )
 
+__all__ = (  # comment about the opening paren
+    # multiline strange comment 0a
+    # multiline strange comment 0b
+    "foo"  # inline comment about foo
+    # multiline strange comment 1a
+    # multiline strange comment 1b
+    ,  # comment about the comma??
+    # comment about bar part a
+    # comment about bar part b
+    "bar"  # inline comment about bar
+    # strange multiline comment comment 2a
+    # strange multiline comment 2b
+    ,
+    # strange multiline comment 3a
+    # strange multiline comment 3b
+)  # comment about the closing paren
+
 ###################################
 # These should all not get flagged:
 ###################################

crates/ruff_linter/resources/test/fixtures/ruff/RUF023.py

@@ -188,6 +188,10 @@ class BezierBuilder4:
         ,
     )
 
+    __slots__ = {"foo", "bar",
+                 "baz", "bingo"
+                 }
+
 ###################################
 # These should all not get flagged:
 ###################################

crates/ruff_linter/resources/test/fixtures/ruff/RUF027_0.py

@@ -68,3 +68,7 @@ def method_calls():
     first = "Wendy"
     last = "Appleseed"
     value.method("{first} {last}")  # RUF027
+
+def format_specifiers():
+    a = 4
+    b = "{a:b} {a:^5}"

crates/ruff_linter/resources/test/fixtures/ruff/RUF027_2.py

@@ -0,0 +1,2 @@
+# 测试eval函数,eval()函数用来执行一个字符串表达式，并返t表达式的值。另外，可以讲字符串转换成列表或元组或字典
+a = "{1: 'a', 2: 'b'}"

crates/ruff_linter/src/checkers/ast/analyze/comprehension.rs

@@ -2,11 +2,14 @@ use ruff_python_ast::Comprehension;
 
 use crate::checkers::ast::Checker;
 use crate::codes::Rule;
-use crate::rules::flake8_simplify;
+use crate::rules::{flake8_simplify, refurb};
 
 /// Run lint rules over a [`Comprehension`] syntax nodes.
 pub(crate) fn comprehension(comprehension: &Comprehension, checker: &mut Checker) {
     if checker.enabled(Rule::InDictKeys) {
         flake8_simplify::rules::key_in_dict_comprehension(checker, comprehension);
     }
+    if checker.enabled(Rule::ReadlinesInFor) {
+        refurb::rules::readlines_in_comprehension(checker, comprehension);
+    }
 }

crates/ruff_linter/src/checkers/ast/analyze/deferred_scopes.rs

@@ -281,17 +281,21 @@ pub(crate) fn deferred_scopes(checker: &mut Checker) {
             }
         }
 
-        if checker.enabled(Rule::UnusedPrivateTypeVar) {
-            flake8_pyi::rules::unused_private_type_var(checker, scope, &mut diagnostics);
-        }
-        if checker.enabled(Rule::UnusedPrivateProtocol) {
-            flake8_pyi::rules::unused_private_protocol(checker, scope, &mut diagnostics);
-        }
-        if checker.enabled(Rule::UnusedPrivateTypeAlias) {
-            flake8_pyi::rules::unused_private_type_alias(checker, scope, &mut diagnostics);
-        }
-        if checker.enabled(Rule::UnusedPrivateTypedDict) {
-            flake8_pyi::rules::unused_private_typed_dict(checker, scope, &mut diagnostics);
+        if checker.source_type.is_stub()
+            || matches!(scope.kind, ScopeKind::Module | ScopeKind::Function(_))
+        {
+            if checker.enabled(Rule::UnusedPrivateTypeVar) {
+                flake8_pyi::rules::unused_private_type_var(checker, scope, &mut diagnostics);
+            }
+            if checker.enabled(Rule::UnusedPrivateProtocol) {
+                flake8_pyi::rules::unused_private_protocol(checker, scope, &mut diagnostics);
+            }
+            if checker.enabled(Rule::UnusedPrivateTypeAlias) {
+                flake8_pyi::rules::unused_private_type_alias(checker, scope, &mut diagnostics);
+            }
+            if checker.enabled(Rule::UnusedPrivateTypedDict) {
+                flake8_pyi::rules::unused_private_typed_dict(checker, scope, &mut diagnostics);
+            }
         }
 
         if checker.enabled(Rule::AsyncioDanglingTask) {

crates/ruff_linter/src/checkers/ast/analyze/statement.rs

@@ -1317,6 +1317,9 @@ pub(crate) fn statement(stmt: &Stmt, checker: &mut Checker) {
             if checker.enabled(Rule::UnnecessaryDictIndexLookup) {
                 pylint::rules::unnecessary_dict_index_lookup(checker, for_stmt);
             }
+            if checker.enabled(Rule::ReadlinesInFor) {
+                refurb::rules::readlines_in_for(checker, for_stmt);
+            }
             if !is_async {
                 if checker.enabled(Rule::ReimplementedBuiltin) {
                     flake8_simplify::rules::convert_for_loop_to_any_all(checker, stmt);

crates/ruff_linter/src/checkers/ast/analyze/string_like.rs

@@ -2,10 +2,16 @@ use ruff_python_ast::StringLike;
 
 use crate::checkers::ast::Checker;
 use crate::codes::Rule;
-use crate::rules::{flake8_bandit, flake8_pyi};
+use crate::rules::{flake8_bandit, flake8_pyi, ruff};
 
 /// Run lint rules over a [`StringLike`] syntax nodes.
 pub(crate) fn string_like(string_like: StringLike, checker: &mut Checker) {
+    if checker.any_enabled(&[
+        Rule::AmbiguousUnicodeCharacterString,
+        Rule::AmbiguousUnicodeCharacterDocstring,
+    ]) {
+        ruff::rules::ambiguous_unicode_character_string(checker, string_like);
+    }
     if checker.enabled(Rule::HardcodedBindAllInterfaces) {
         flake8_bandit::rules::hardcoded_bind_all_interfaces(checker, string_like);
     }

crates/ruff_linter/src/checkers/ast/mod.rs

@@ -40,7 +40,7 @@ use ruff_diagnostics::{Diagnostic, IsolationLevel};
 use ruff_notebook::{CellOffsets, NotebookIndex};
 use ruff_python_ast::all::{extract_all_names, DunderAllFlags};
 use ruff_python_ast::helpers::{
-    collect_import_from_member, extract_handled_exceptions, to_module_path,
+    collect_import_from_member, extract_handled_exceptions, is_docstring_stmt, to_module_path,
 };
 use ruff_python_ast::identifier::Identifier;
 use ruff_python_ast::str::trailing_quote;
@@ -71,6 +71,38 @@ mod analyze;
 mod annotation;
 mod deferred;
 
+/// State representing whether a docstring is expected or not for the next statement.
+#[derive(Default, Debug, Copy, Clone, PartialEq)]
+enum DocstringState {
+    /// The next statement is expected to be a docstring, but not necessarily so.
+    ///
+    /// For example, in the following code:
+    ///
+    /// ```python
+    /// class Foo:
+    ///     pass
+    ///
+    ///
+    /// def bar(x, y):
+    ///     """Docstring."""
+    ///     return x +  y
+    /// ```
+    ///
+    /// For `Foo`, the state is expected when the checker is visiting the class
+    /// body but isn't going to be present. While, for `bar` function, the docstring
+    /// is expected and present.
+    #[default]
+    Expected,
+    Other,
+}
+
+impl DocstringState {
+    /// Returns `true` if the next statement is expected to be a docstring.
+    const fn is_expected(self) -> bool {
+        matches!(self, DocstringState::Expected)
+    }
+}
+
 pub(crate) struct Checker<'a> {
     /// The [`Path`] to the file under analysis.
     path: &'a Path,
@@ -114,6 +146,8 @@ pub(crate) struct Checker<'a> {
     pub(crate) flake8_bugbear_seen: Vec<TextRange>,
     /// The end offset of the last visited statement.
     last_stmt_end: TextSize,
+    /// A state describing if a docstring is expected or not.
+    docstring_state: DocstringState,
 }
 
 impl<'a> Checker<'a> {
@@ -153,6 +187,7 @@ impl<'a> Checker<'a> {
             cell_offsets,
             notebook_index,
             last_stmt_end: TextSize::default(),
+            docstring_state: DocstringState::default(),
         }
     }
 }
@@ -305,19 +340,16 @@ where
             self.semantic.flags -= SemanticModelFlags::IMPORT_BOUNDARY;
         }
 
-        // Track whether we've seen docstrings, non-imports, etc.
+        // Track whether we've seen module docstrings, non-imports, etc.
         match stmt {
             Stmt::Expr(ast::StmtExpr { value, .. })
-                if !self
-                    .semantic
-                    .flags
-                    .intersects(SemanticModelFlags::MODULE_DOCSTRING)
+                if !self.semantic.seen_module_docstring_boundary()
                     && value.is_string_literal_expr() =>
             {
-                self.semantic.flags |= SemanticModelFlags::MODULE_DOCSTRING;
+                self.semantic.flags |= SemanticModelFlags::MODULE_DOCSTRING_BOUNDARY;
             }
             Stmt::ImportFrom(ast::StmtImportFrom { module, names, .. }) => {
-                self.semantic.flags |= SemanticModelFlags::MODULE_DOCSTRING;
+                self.semantic.flags |= SemanticModelFlags::MODULE_DOCSTRING_BOUNDARY;
 
                 // Allow __future__ imports until we see a non-__future__ import.
                 if let Some("__future__") = module.as_deref() {
@@ -332,11 +364,11 @@ where
                 }
             }
             Stmt::Import(_) => {
-                self.semantic.flags |= SemanticModelFlags::MODULE_DOCSTRING;
+                self.semantic.flags |= SemanticModelFlags::MODULE_DOCSTRING_BOUNDARY;
                 self.semantic.flags |= SemanticModelFlags::FUTURES_BOUNDARY;
             }
             _ => {
-                self.semantic.flags |= SemanticModelFlags::MODULE_DOCSTRING;
+                self.semantic.flags |= SemanticModelFlags::MODULE_DOCSTRING_BOUNDARY;
                 self.semantic.flags |= SemanticModelFlags::FUTURES_BOUNDARY;
                 if !(self.semantic.seen_import_boundary()
                     || helpers::is_assignment_to_a_dunder(stmt)
@@ -353,6 +385,16 @@ where
         // the node.
         let flags_snapshot = self.semantic.flags;
 
+        // Update the semantic model if it is in a docstring. This should be done after the
+        // flags snapshot to ensure that it gets reset once the statement is analyzed.
+        if self.docstring_state.is_expected() {
+            if is_docstring_stmt(stmt) {
+                self.semantic.flags |= SemanticModelFlags::DOCSTRING;
+            }
+            // Reset the state irrespective of whether the statement is a docstring or not.
+            self.docstring_state = DocstringState::Other;
+        }
+
         // Step 1: Binding
         match stmt {
             Stmt::AugAssign(ast::StmtAugAssign {
@@ -654,6 +696,8 @@ where
                     self.semantic.set_globals(globals);
                 }
 
+                // Set the docstring state before visiting the class body.
+                self.docstring_state = DocstringState::Expected;
                 self.visit_body(body);
             }
             Stmt::TypeAlias(ast::StmtTypeAlias {
@@ -1288,6 +1332,16 @@ where
                 self.semantic.flags |= SemanticModelFlags::F_STRING;
                 visitor::walk_expr(self, expr);
             }
+            Expr::NamedExpr(ast::ExprNamedExpr {
+                target,
+                value,
+                range: _,
+            }) => {
+                self.visit_expr(value);
+
+                self.semantic.flags |= SemanticModelFlags::NAMED_EXPRESSION_ASSIGNMENT;
+                self.visit_expr(target);
+            }
             _ => visitor::walk_expr(self, expr),
         }
 
@@ -1504,6 +1558,8 @@ impl<'a> Checker<'a> {
             unreachable!("Generator expression must contain at least one generator");
         };
 
+        let flags = self.semantic.flags;
+
         // Generators are compiled as nested functions. (This may change with PEP 709.)
         // As such, the `iter` of the first generator is evaluated in the outer scope, while all
         // subsequent nodes are evaluated in the inner scope.
@@ -1533,14 +1589,22 @@ impl<'a> Checker<'a> {
         // `x` is local to `foo`, and the `T` in `y=T` skips the class scope when resolving.
         self.visit_expr(&generator.iter);
         self.semantic.push_scope(ScopeKind::Generator);
+
+        self.semantic.flags = flags | SemanticModelFlags::COMPREHENSION_ASSIGNMENT;
         self.visit_expr(&generator.target);
+        self.semantic.flags = flags;
+
         for expr in &generator.ifs {
             self.visit_boolean_test(expr);
         }
 
         for generator in iterator {
             self.visit_expr(&generator.iter);
+
+            self.semantic.flags = flags | SemanticModelFlags::COMPREHENSION_ASSIGNMENT;
             self.visit_expr(&generator.target);
+            self.semantic.flags = flags;
+
             for expr in &generator.ifs {
                 self.visit_boolean_test(expr);
             }
@@ -1739,11 +1803,21 @@ impl<'a> Checker<'a> {
             return;
         }
 
+        // A binding within a `for` must be a loop variable, as in:
+        // ```python
+        // for x in range(10):
+        //     ...
+        // ```
         if parent.is_for_stmt() {
             self.add_binding(id, expr.range(), BindingKind::LoopVar, flags);
             return;
         }
 
+        // A binding within a `with` must be an item, as in:
+        // ```python
+        // with open("file.txt") as fp:
+        //     ...
+        // ```
         if parent.is_with_stmt() {
             self.add_binding(id, expr.range(), BindingKind::WithItemVar, flags);
             return;
@@ -1799,17 +1873,26 @@ impl<'a> Checker<'a> {
         }
 
         // If the expression is the left-hand side of a walrus operator, then it's a named
-        // expression assignment.
-        if self
-            .semantic
-            .current_expressions()
-            .filter_map(Expr::as_named_expr_expr)
-            .any(|parent| parent.target.as_ref() == expr)
-        {
+        // expression assignment, as in:
+        // ```python
+        // if (x := 10) > 5:
+        //     ...
+        // ```
+        if self.semantic.in_named_expression_assignment() {
             self.add_binding(id, expr.range(), BindingKind::NamedExprAssignment, flags);
             return;
         }
 
+        // If the expression is part of a comprehension target, then it's a comprehension variable
+        // assignment, as in:
+        // ```python
+        // [x for x in range(10)]
+        // ```
+        if self.semantic.in_comprehension_assignment() {
+            self.add_binding(id, expr.range(), BindingKind::ComprehensionVar, flags);
+            return;
+        }
+
         self.add_binding(id, expr.range(), BindingKind::Assignment, flags);
     }
 
@@ -1925,6 +2008,8 @@ impl<'a> Checker<'a> {
                 };
 
                 self.visit_parameters(parameters);
+                // Set the docstring state before visiting the function body.
+                self.docstring_state = DocstringState::Expected;
                 self.visit_body(body);
             }
         }

crates/ruff_linter/src/checkers/tokens.rs

@@ -6,17 +6,14 @@ use ruff_notebook::CellOffsets;
 use ruff_python_ast::PySourceType;
 use ruff_python_codegen::Stylist;
 use ruff_python_parser::lexer::LexResult;
-use ruff_python_parser::Tok;
 
 use ruff_diagnostics::Diagnostic;
 use ruff_python_index::Indexer;
 use ruff_source_file::Locator;
 
 use crate::directives::TodoComment;
-use crate::lex::docstring_detection::StateMachine;
 use crate::registry::{AsRule, Rule};
 use crate::rules::pycodestyle::rules::BlankLinesChecker;
-use crate::rules::ruff::rules::Context;
 use crate::rules::{
     eradicate, flake8_commas, flake8_executable, flake8_fixme, flake8_implicit_str_concat,
     flake8_pyi, flake8_quotes, flake8_todos, pycodestyle, pygrep_hooks, pylint, pyupgrade, ruff,
@@ -66,31 +63,15 @@ pub(crate) fn check_tokens(
         pylint::rules::empty_comments(&mut diagnostics, indexer, locator);
     }
 
-    if settings.rules.any_enabled(&[
-        Rule::AmbiguousUnicodeCharacterString,
-        Rule::AmbiguousUnicodeCharacterDocstring,
-        Rule::AmbiguousUnicodeCharacterComment,
-    ]) {
-        let mut state_machine = StateMachine::default();
-        for &(ref tok, range) in tokens.iter().flatten() {
-            let is_docstring = state_machine.consume(tok);
-            let context = match tok {
-                Tok::String { .. } => {
-                    if is_docstring {
-                        Context::Docstring
-                    } else {
-                        Context::String
-                    }
-                }
-                Tok::FStringMiddle { .. } => Context::String,
-                Tok::Comment(_) => Context::Comment,
-                _ => continue,
-            };
-            ruff::rules::ambiguous_unicode_character(
+    if settings
+        .rules
+        .enabled(Rule::AmbiguousUnicodeCharacterComment)
+    {
+        for range in indexer.comment_ranges() {
+            ruff::rules::ambiguous_unicode_character_comment(
                 &mut diagnostics,
                 locator,
-                range,
-                context,
+                *range,
                 settings,
             );
         }

crates/ruff_linter/src/codes.rs

@@ -1025,6 +1025,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         #[allow(deprecated)]
         (Refurb, "113") => (RuleGroup::Nursery, rules::refurb::rules::RepeatedAppend),
         (Refurb, "118") => (RuleGroup::Preview, rules::refurb::rules::ReimplementedOperator),
+        (Refurb, "129") => (RuleGroup::Preview, rules::refurb::rules::ReadlinesInFor),
         #[allow(deprecated)]
         (Refurb, "131") => (RuleGroup::Nursery, rules::refurb::rules::DeleteFullSlice),
         #[allow(deprecated)]

crates/ruff_linter/src/registry.rs

@@ -256,8 +256,6 @@ impl Rule {
             | Rule::MixedSpacesAndTabs
             | Rule::TrailingWhitespace => LintSource::PhysicalLines,
             Rule::AmbiguousUnicodeCharacterComment
-            | Rule::AmbiguousUnicodeCharacterDocstring
-            | Rule::AmbiguousUnicodeCharacterString
             | Rule::AvoidableEscapedQuote
             | Rule::BadQuotesDocstring
             | Rule::BadQuotesInlineString

crates/ruff_linter/src/renamer.rs

@@ -248,6 +248,7 @@ impl Renamer {
             | BindingKind::Assignment
             | BindingKind::BoundException
             | BindingKind::LoopVar
+            | BindingKind::ComprehensionVar
             | BindingKind::WithItemVar
             | BindingKind::Global
             | BindingKind::Nonlocal(_)

crates/ruff_linter/src/rules/flake8_async/rules/open_sleep_or_subprocess_call.rs

@@ -118,8 +118,7 @@ fn is_open_call_from_pathlib(func: &Expr, semantic: &SemanticModel) -> bool {
 
     let binding = semantic.binding(binding_id);
 
-    let Some(Expr::Call(call)) = analyze::typing::find_binding_value(&name.id, binding, semantic)
-    else {
+    let Some(Expr::Call(call)) = analyze::typing::find_binding_value(binding, semantic) else {
         return false;
     };
 

crates/ruff_linter/src/rules/flake8_bandit/rules/hardcoded_bind_all_interfaces.rs

@@ -40,7 +40,9 @@ impl Violation for HardcodedBindAllInterfaces {
 pub(crate) fn hardcoded_bind_all_interfaces(checker: &mut Checker, string: StringLike) {
     let is_bind_all_interface = match string {
         StringLike::StringLiteral(ast::ExprStringLiteral { value, .. }) => value == "0.0.0.0",
-        StringLike::FStringLiteral(ast::FStringLiteralElement { value, .. }) => value == "0.0.0.0",
+        StringLike::FStringLiteral(ast::FStringLiteralElement { value, .. }) => {
+            &**value == "0.0.0.0"
+        }
         StringLike::BytesLiteral(_) => return,
     };
 

crates/ruff_linter/src/rules/flake8_pyi/snapshots/ruff_linter__rules__flake8_pyi__tests__PYI049_PYI049.py.snap

@@ -15,13 +15,11 @@ PYI049.py:9:7: PYI049 Private TypedDict `_UnusedTypedDict2` is never used
 10 |     bar: int
    |
 
-PYI049.py:20:1: PYI049 Private TypedDict `_UnusedTypedDict3` is never used
+PYI049.py:21:1: PYI049 Private TypedDict `_UnusedTypedDict3` is never used
    |
-18 |     bar: list[int]
-19 | 
-20 | _UnusedTypedDict3 = TypedDict("_UnusedTypedDict3", {"foo": int})
+21 | _UnusedTypedDict3 = TypedDict("_UnusedTypedDict3", {"foo": int})
    | ^^^^^^^^^^^^^^^^^ PYI049
-21 | _UsedTypedDict3 = TypedDict("_UsedTypedDict3", {"bar": bytes})
+22 | _UsedTypedDict3 = TypedDict("_UsedTypedDict3", {"bar": bytes})
    |
 
 

crates/ruff_linter/src/rules/flake8_pyi/snapshots/ruff_linter__rules__flake8_pyi__tests__PYI049_PYI049.pyi.snap

@@ -24,4 +24,13 @@ PYI049.pyi:34:1: PYI049 Private TypedDict `_UnusedTypedDict3` is never used
 35 | _UsedTypedDict3 = TypedDict("_UsedTypedDict3", {"bar": bytes})
    |
 
+PYI049.pyi:43:11: PYI049 Private TypedDict `_UnusedTypeDict4` is never used
+   |
+41 | # scope (unlike in `.py` files).
+42 | class _CustomClass3:
+43 |     class _UnusedTypeDict4(TypedDict):
+   |           ^^^^^^^^^^^^^^^^ PYI049
+44 |         pass
+   |
+
 

crates/ruff_linter/src/rules/flake8_simplify/rules/enumerate_for_loop.rs

@@ -49,6 +49,11 @@ impl Violation for EnumerateForLoop {
 
 /// SIM113
 pub(crate) fn enumerate_for_loop(checker: &mut Checker, for_stmt: &ast::StmtFor) {
+    // If the loop is async, abort.
+    if for_stmt.is_async {
+        return;
+    }
+
     // If the loop contains a `continue`, abort.
     let mut visitor = LoopControlFlowVisitor::default();
     visitor.visit_body(&for_stmt.body);
@@ -76,8 +81,7 @@ pub(crate) fn enumerate_for_loop(checker: &mut Checker, for_stmt: &ast::StmtFor)
             }
 
             // Ensure that the index variable was initialized to 0.
-            let Some(value) = typing::find_binding_value(&index.id, binding, checker.semantic())
-            else {
+            let Some(value) = typing::find_binding_value(binding, checker.semantic()) else {
                 continue;
             };
             if !matches!(

crates/ruff_linter/src/rules/flake8_use_pathlib/rules/os_path_getatime.rs

@@ -10,7 +10,7 @@ use ruff_macros::{derive_message_formats, violation};
 ///
 /// When possible, using `Path` object methods such as `Path.stat()` can
 /// improve readability over the `os` module's counterparts (e.g.,
-/// `os.path.getsize()`).
+/// `os.path.getatime()`).
 ///
 /// Note that `os` functions may be preferable if performance is a concern,
 /// e.g., in hot loops.
@@ -19,19 +19,19 @@ use ruff_macros::{derive_message_formats, violation};
 /// ```python
 /// import os
 ///
-/// os.path.getsize(__file__)
+/// os.path.getatime(__file__)
 /// ```
 ///
 /// Use instead:
 /// ```python
 /// from pathlib import Path
 ///
-/// Path(__file__).stat().st_size
+/// Path(__file__).stat().st_atime
 /// ```
 ///
 /// ## References
 /// - [Python documentation: `Path.stat`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.stat)
-/// - [Python documentation: `os.path.getsize`](https://docs.python.org/3/library/os.path.html#os.path.getsize)
+/// - [Python documentation: `os.path.getatime`](https://docs.python.org/3/library/os.path.html#os.path.getatime)
 /// - [PEP 428](https://peps.python.org/pep-0428/)
 /// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#correspondence-to-tools-in-the-os-module)
 /// - [Why you should be using pathlib](https://treyhunner.com/2018/12/why-you-should-be-using-pathlib/)

crates/ruff_linter/src/rules/flake8_use_pathlib/rules/os_path_getctime.rs

@@ -2,7 +2,7 @@ use ruff_diagnostics::Violation;
 use ruff_macros::{derive_message_formats, violation};
 
 /// ## What it does
-/// Checks for uses of `os.path.getatime`.
+/// Checks for uses of `os.path.getctime`.
 ///
 /// ## Why is this bad?
 /// `pathlib` offers a high-level API for path manipulation, as compared to
@@ -10,7 +10,7 @@ use ruff_macros::{derive_message_formats, violation};
 ///
 /// When possible, using `Path` object methods such as `Path.stat()` can
 /// improve readability over the `os` module's counterparts (e.g.,
-/// `os.path.getsize()`).
+/// `os.path.getctime()`).
 ///
 /// Note that `os` functions may be preferable if performance is a concern,
 /// e.g., in hot loops.
@@ -19,19 +19,19 @@ use ruff_macros::{derive_message_formats, violation};
 /// ```python
 /// import os
 ///
-/// os.path.getsize(__file__)
+/// os.path.getctime(__file__)
 /// ```
 ///
 /// Use instead:
 /// ```python
 /// from pathlib import Path
 ///
-/// Path(__file__).stat().st_size
+/// Path(__file__).stat().st_ctime
 /// ```
 ///
 /// ## References
 /// - [Python documentation: `Path.stat`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.stat)
-/// - [Python documentation: `os.path.getsize`](https://docs.python.org/3/library/os.path.html#os.path.getsize)
+/// - [Python documentation: `os.path.getctime`](https://docs.python.org/3/library/os.path.html#os.path.getctime)
 /// - [PEP 428](https://peps.python.org/pep-0428/)
 /// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#correspondence-to-tools-in-the-os-module)
 /// - [Why you should be using pathlib](https://treyhunner.com/2018/12/why-you-should-be-using-pathlib/)

crates/ruff_linter/src/rules/flake8_use_pathlib/rules/os_path_getmtime.rs

@@ -2,7 +2,7 @@ use ruff_diagnostics::Violation;
 use ruff_macros::{derive_message_formats, violation};
 
 /// ## What it does
-/// Checks for uses of `os.path.getatime`.
+/// Checks for uses of `os.path.getmtime`.
 ///
 /// ## Why is this bad?
 /// `pathlib` offers a high-level API for path manipulation, as compared to
@@ -10,7 +10,7 @@ use ruff_macros::{derive_message_formats, violation};
 ///
 /// When possible, using `Path` object methods such as `Path.stat()` can
 /// improve readability over the `os` module's counterparts (e.g.,
-/// `os.path.getsize()`).
+/// `os.path.getmtime()`).
 ///
 /// Note that `os` functions may be preferable if performance is a concern,
 /// e.g., in hot loops.
@@ -19,19 +19,19 @@ use ruff_macros::{derive_message_formats, violation};
 /// ```python
 /// import os
 ///
-/// os.path.getsize(__file__)
+/// os.path.getmtime(__file__)
 /// ```
 ///
 /// Use instead:
 /// ```python
 /// from pathlib import Path
 ///
-/// Path(__file__).stat().st_size
+/// Path(__file__).stat().st_mtime
 /// ```
 ///
 /// ## References
 /// - [Python documentation: `Path.stat`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.stat)
-/// - [Python documentation: `os.path.getsize`](https://docs.python.org/3/library/os.path.html#os.path.getsize)
+/// - [Python documentation: `os.path.getmtime`](https://docs.python.org/3/library/os.path.html#os.path.getmtime)
 /// - [PEP 428](https://peps.python.org/pep-0428/)
 /// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#correspondence-to-tools-in-the-os-module)
 /// - [Why you should be using pathlib](https://treyhunner.com/2018/12/why-you-should-be-using-pathlib/)

crates/ruff_linter/src/rules/flynt/helpers.rs

@@ -15,7 +15,7 @@ fn to_f_string_expression_element(inner: &Expr) -> ast::FStringElement {
 /// Convert a string to a [`ast::FStringElement::Literal`].
 pub(super) fn to_f_string_literal_element(s: &str) -> ast::FStringElement {
     ast::FStringElement::Literal(ast::FStringLiteralElement {
-        value: s.to_owned(),
+        value: s.to_string().into_boxed_str(),
         range: TextRange::default(),
     })
 }
@@ -53,7 +53,7 @@ pub(super) fn to_f_string_element(expr: &Expr) -> Option<ast::FStringElement> {
     match expr {
         Expr::StringLiteral(ast::ExprStringLiteral { value, range }) => {
             Some(ast::FStringElement::Literal(ast::FStringLiteralElement {
-                value: value.to_string(),
+                value: value.to_string().into_boxed_str(),
                 range: *range,
             }))
         }

crates/ruff_linter/src/rules/isort/mod.rs

@@ -419,23 +419,20 @@ mod tests {
         Ok(())
     }
 
-    // Test currently disabled as line endings are automatically converted to
-    // platform-appropriate ones in CI/CD #[test_case(Path::new("
-    // line_ending_crlf.py"))] #[test_case(Path::new("line_ending_lf.py"))]
-    // fn source_code_style(path: &Path) -> Result<()> {
-    //     let snapshot = format!("{}", path.to_string_lossy());
-    //     let diagnostics = test_path(
-    //         Path::new("isort")
-    //             .join(path)
-    //             .as_path(),
-    //         &LinterSettings {
-    //             src: vec![test_resource_path("fixtures/isort")],
-    //             ..LinterSettings::for_rule(Rule::UnsortedImports)
-    //         },
-    //     )?;
-    //     crate::assert_messages!(snapshot, diagnostics);
-    //     Ok(())
-    // }
+    #[test_case(Path::new("line_ending_crlf.py"))]
+    #[test_case(Path::new("line_ending_lf.py"))]
+    fn source_code_style(path: &Path) -> Result<()> {
+        let snapshot = format!("{}", path.to_string_lossy());
+        let diagnostics = test_path(
+            Path::new("isort").join(path).as_path(),
+            &LinterSettings {
+                src: vec![test_resource_path("fixtures/isort")],
+                ..LinterSettings::for_rule(Rule::UnsortedImports)
+            },
+        )?;
+        crate::assert_messages!(snapshot, diagnostics);
+        Ok(())
+    }
 
     #[test_case(Path::new("separate_local_folder_imports.py"))]
     fn known_local_folder(path: &Path) -> Result<()> {

crates/ruff_linter/src/rules/isort/snapshots/ruff_linter__rules__isort__tests__line_ending_crlf.py.snap

@@ -0,0 +1,23 @@
+---
+source: crates/ruff_linter/src/rules/isort/mod.rs
+---
+line_ending_crlf.py:1:1: I001 [*] Import block is un-sorted or un-formatted
+  |
+1 | / from long_module_name import member_one, member_two, member_three, member_four, member_five
+2 | | 
+  | |_^ I001
+  |
+  = help: Organize imports
+
+ℹ Safe fix
+1   |-from long_module_name import member_one, member_two, member_three, member_four, member_five
+  1 |+from long_module_name import (
+  2 |+    member_five,
+  3 |+    member_four,
+  4 |+    member_one,
+  5 |+    member_three,
+  6 |+    member_two,
+  7 |+)
+2 8 | 
+
+

crates/ruff_linter/src/rules/isort/snapshots/ruff_linter__rules__isort__tests__line_ending_lf.py.snap

@@ -0,0 +1,23 @@
+---
+source: crates/ruff_linter/src/rules/isort/mod.rs
+---
+line_ending_lf.py:1:1: I001 [*] Import block is un-sorted or un-formatted
+  |
+1 | / from long_module_name import member_one, member_two, member_three, member_four, member_five
+2 | | 
+  | |_^ I001
+  |
+  = help: Organize imports
+
+ℹ Safe fix
+1   |-from long_module_name import member_one, member_two, member_three, member_four, member_five
+  1 |+from long_module_name import (
+  2 |+    member_five,
+  3 |+    member_four,
+  4 |+    member_one,
+  5 |+    member_three,
+  6 |+    member_two,
+  7 |+)
+2 8 | 
+
+

crates/ruff_linter/src/rules/pandas_vet/helpers.rs

@@ -47,6 +47,7 @@ pub(super) fn test_expression(expr: &Expr, semantic: &SemanticModel) -> Resoluti
                         | BindingKind::Assignment
                         | BindingKind::NamedExprAssignment
                         | BindingKind::LoopVar
+                        | BindingKind::ComprehensionVar
                         | BindingKind::Global
                         | BindingKind::Nonlocal(_) => Resolution::RelevantLocal,
                         BindingKind::Import(import) if matches!(import.call_path(), ["pandas"]) => {

crates/ruff_linter/src/rules/perflint/rules/unnecessary_list_cast.rs

@@ -1,5 +1,6 @@
 use ruff_diagnostics::{AlwaysFixableViolation, Diagnostic, Edit, Fix};
 use ruff_macros::{derive_message_formats, violation};
+use ruff_python_ast::statement_visitor::{walk_stmt, StatementVisitor};
 use ruff_python_ast::{self as ast, Arguments, Expr, Stmt};
 use ruff_python_semantic::analyze::typing::find_assigned_value;
 use ruff_text_size::TextRange;
@@ -98,22 +99,25 @@ pub(crate) fn unnecessary_list_cast(checker: &mut Checker, iter: &Expr, body: &[
             range: iterable_range,
             ..
         }) => {
-            // If the variable is being appended to, don't suggest removing the cast:
-            //
-            // ```python
-            // items = ["foo", "bar"]
-            // for item in list(items):
-            //    items.append("baz")
-            // ```
-            //
-            // Here, removing the `list()` cast would change the behavior of the code.
-            if body.iter().any(|stmt| match_append(stmt, id)) {
-                return;
-            }
             let Some(value) = find_assigned_value(id, checker.semantic()) else {
                 return;
             };
             if matches!(value, Expr::Tuple(_) | Expr::List(_) | Expr::Set(_)) {
+                // If the variable is being modified to, don't suggest removing the cast:
+                //
+                // ```python
+                // items = ["foo", "bar"]
+                // for item in list(items):
+                //    items.append("baz")
+                // ```
+                //
+                // Here, removing the `list()` cast would change the behavior of the code.
+                let mut visitor = MutationVisitor::new(id);
+                visitor.visit_body(body);
+                if visitor.is_mutated {
+                    return;
+                }
+
                 let mut diagnostic = Diagnostic::new(UnnecessaryListCast, *list_range);
                 diagnostic.set_fix(remove_cast(*list_range, *iterable_range));
                 checker.diagnostics.push(diagnostic);
@@ -123,28 +127,6 @@ pub(crate) fn unnecessary_list_cast(checker: &mut Checker, iter: &Expr, body: &[
     }
 }
 
-/// Check if a statement is an `append` call to a given identifier.
-///
-/// For example, `foo.append(bar)` would return `true` if `id` is `foo`.
-fn match_append(stmt: &Stmt, id: &str) -> bool {
-    let Some(ast::StmtExpr { value, .. }) = stmt.as_expr_stmt() else {
-        return false;
-    };
-    let Some(ast::ExprCall { func, .. }) = value.as_call_expr() else {
-        return false;
-    };
-    let Some(ast::ExprAttribute { value, attr, .. }) = func.as_attribute_expr() else {
-        return false;
-    };
-    if attr != "append" {
-        return false;
-    }
-    let Some(ast::ExprName { id: target_id, .. }) = value.as_name_expr() else {
-        return false;
-    };
-    target_id == id
-}
-
 /// Generate a [`Fix`] to remove a `list` cast from an expression.
 fn remove_cast(list_range: TextRange, iterable_range: TextRange) -> Fix {
     Fix::safe_edits(
@@ -152,3 +134,95 @@ fn remove_cast(list_range: TextRange, iterable_range: TextRange) -> Fix {
         [Edit::deletion(iterable_range.end(), list_range.end())],
     )
 }
+
+/// A [`StatementVisitor`] that (conservatively) identifies mutations to a variable.
+#[derive(Default)]
+pub(crate) struct MutationVisitor<'a> {
+    pub(crate) target: &'a str,
+    pub(crate) is_mutated: bool,
+}
+
+impl<'a> MutationVisitor<'a> {
+    pub(crate) fn new(target: &'a str) -> Self {
+        Self {
+            target,
+            is_mutated: false,
+        }
+    }
+}
+
+impl<'a, 'b> StatementVisitor<'b> for MutationVisitor<'a>
+where
+    'b: 'a,
+{
+    fn visit_stmt(&mut self, stmt: &'b Stmt) {
+        if match_mutation(stmt, self.target) {
+            self.is_mutated = true;
+        } else {
+            walk_stmt(self, stmt);
+        }
+    }
+}
+
+/// Check if a statement is (probably) a modification to the list assigned to the given identifier.
+///
+/// For example, `foo.append(bar)` would return `true` if `id` is `foo`.
+fn match_mutation(stmt: &Stmt, id: &str) -> bool {
+    match stmt {
+        // Ex) `foo.append(bar)`
+        Stmt::Expr(ast::StmtExpr { value, .. }) => {
+            let Some(ast::ExprCall { func, .. }) = value.as_call_expr() else {
+                return false;
+            };
+            let Some(ast::ExprAttribute { value, attr, .. }) = func.as_attribute_expr() else {
+                return false;
+            };
+            if !matches!(
+                attr.as_str(),
+                "append" | "insert" | "extend" | "remove" | "pop" | "clear" | "reverse" | "sort"
+            ) {
+                return false;
+            }
+            let Some(ast::ExprName { id: target_id, .. }) = value.as_name_expr() else {
+                return false;
+            };
+            target_id == id
+        }
+        // Ex) `foo[0] = bar`
+        Stmt::Assign(ast::StmtAssign { targets, .. }) => targets.iter().any(|target| {
+            if let Some(ast::ExprSubscript { value: target, .. }) = target.as_subscript_expr() {
+                if let Some(ast::ExprName { id: target_id, .. }) = target.as_name_expr() {
+                    return target_id == id;
+                }
+            }
+            false
+        }),
+        // Ex) `foo += bar`
+        Stmt::AugAssign(ast::StmtAugAssign { target, .. }) => {
+            if let Some(ast::ExprName { id: target_id, .. }) = target.as_name_expr() {
+                target_id == id
+            } else {
+                false
+            }
+        }
+        // Ex) `foo[0]: int = bar`
+        Stmt::AnnAssign(ast::StmtAnnAssign { target, .. }) => {
+            if let Some(ast::ExprSubscript { value: target, .. }) = target.as_subscript_expr() {
+                if let Some(ast::ExprName { id: target_id, .. }) = target.as_name_expr() {
+                    return target_id == id;
+                }
+            }
+            false
+        }
+        // Ex) `del foo[0]`
+        Stmt::Delete(ast::StmtDelete { targets, .. }) => targets.iter().any(|target| {
+            if let Some(ast::ExprSubscript { value: target, .. }) = target.as_subscript_expr() {
+                if let Some(ast::ExprName { id: target_id, .. }) = target.as_name_expr() {
+                    return target_id == id;
+                }
+            }
+            false
+        }),
+        _ => false,
+    }
+}

crates/ruff_linter/src/rules/perflint/snapshots/ruff_linter__rules__perflint__tests__PERF101_PERF101.py.snap

@@ -178,7 +178,7 @@ PERF101.py:34:10: PERF101 [*] Do not cast an iterable to `list` before iterating
    34 |+for i in {1, 2, 3}:  # PERF101
 37 35 |     pass
 38 36 | 
-39 37 | for i in list(foo_dict):  # Ok
+39 37 | for i in list(foo_dict):  # OK
 
 PERF101.py:57:10: PERF101 [*] Do not cast an iterable to `list` before iterating over it
    |
@@ -192,7 +192,7 @@ PERF101.py:57:10: PERF101 [*] Do not cast an iterable to `list` before iterating
    = help: Remove `list()` cast
 
 ℹ Safe fix
-54 54 | for i in list(foo_list):  # Ok
+54 54 | for i in list(foo_list):  # OK
 55 55 |     foo_list.append(i + 1)
 56 56 | 
 57    |-for i in list(foo_list):  # PERF101
@@ -218,5 +218,7 @@ PERF101.py:69:10: PERF101 [*] Do not cast an iterable to `list` before iterating
 69    |-for i in list(nested_tuple):  # PERF101
    69 |+for i in nested_tuple:  # PERF101
 70 70 |     pass
+71 71 | 
+72 72 | for i in list(foo_list):  # OK
 
 

crates/ruff_linter/src/rules/pydocstyle/rules/indent.rs

@@ -87,12 +87,17 @@ impl Violation for IndentWithSpaces {
 ///     """
 /// ```
 ///
+/// ## Formatter compatibility
+/// We recommend against using this rule alongside the [formatter]. The
+/// formatter enforces consistent indentation, making the rule redundant.
+///
 /// ## References
 /// - [PEP 257 – Docstring Conventions](https://peps.python.org/pep-0257/)
 /// - [NumPy Style Guide](https://numpydoc.readthedocs.io/en/latest/format.html)
 /// - [Google Python Style Guide - Docstrings](https://google.github.io/styleguide/pyguide.html#38-comments-and-docstrings)
 ///
 /// [PEP 257]: https://peps.python.org/pep-0257/
+/// [formatter]: https://docs.astral.sh/ruff/formatter/
 #[violation]
 pub struct UnderIndentation;
 

crates/ruff_linter/src/rules/pydocstyle/rules/triple_quotes.rs

@@ -27,10 +27,16 @@ use crate::docstrings::Docstring;
 ///     """Return the pathname of the KOS root directory."""
 /// ```
 ///
+/// ## Formatter compatibility
+/// We recommend against using this rule alongside the [formatter]. The
+/// formatter enforces consistent quotes, making the rule redundant.
+///
 /// ## References
 /// - [PEP 257 – Docstring Conventions](https://peps.python.org/pep-0257/)
 /// - [NumPy Style Guide](https://numpydoc.readthedocs.io/en/latest/format.html)
 /// - [Google Python Style Guide - Docstrings](https://google.github.io/styleguide/pyguide.html#38-comments-and-docstrings)
+///
+/// [formatter]: https://docs.astral.sh/ruff/formatter/
 #[violation]
 pub struct TripleSingleQuotes {
     expected_quote: Quote,

crates/ruff_linter/src/rules/pyflakes/rules/unused_import.rs

@@ -28,6 +28,15 @@ enum UnusedImportContext {
 /// If an import statement is used to check for the availability or existence
 /// of a module, consider using `importlib.util.find_spec` instead.
 ///
+/// If an import statement is used to re-export a symbol as part of a module's
+/// public interface, consider using a "redundant" import alias, which
+/// instructs Ruff (and other tools) to respect the re-export, and avoid
+/// marking it as unused, as in:
+///
+/// ```python
+/// from module import member as member
+/// ```
+///
 /// ## Example
 /// ```python
 /// import numpy as np  # unused import
@@ -54,11 +63,12 @@ enum UnusedImportContext {
 /// ```
 ///
 /// ## Options
-/// - `lint.pyflakes.extend-generics`
+/// - `lint.ignore-init-module-imports`
 ///
 /// ## References
 /// - [Python documentation: `import`](https://docs.python.org/3/reference/simple_stmts.html#the-import-statement)
 /// - [Python documentation: `importlib.util.find_spec`](https://docs.python.org/3/library/importlib.html#importlib.util.find_spec)
+/// - [Typing documentation: interface conventions](https://typing.readthedocs.io/en/latest/source/libraries.html#library-interface-public-and-private-symbols)
 #[violation]
 pub struct UnusedImport {
     name: String,

crates/ruff_linter/src/rules/pylint/rules/literal_membership.rs

@@ -1,6 +1,7 @@
 use ruff_diagnostics::{AlwaysFixableViolation, Diagnostic, Edit, Fix};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::{self as ast, CmpOp, Expr};
+use ruff_python_semantic::analyze::typing;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -25,7 +26,8 @@ use crate::checkers::ast::Checker;
 /// ## Fix safety
 /// This rule's fix is marked as unsafe, as the use of a `set` literal will
 /// error at runtime if the sequence contains unhashable elements (like lists
-/// or dictionaries).
+/// or dictionaries). While Ruff will attempt to infer the hashability of the
+/// elements, it may not always be able to do so.
 ///
 /// ## References
 /// - [What’s New In Python 3.2](https://docs.python.org/3/whatsnew/3.2.html#optimizations)
@@ -57,7 +59,40 @@ pub(crate) fn literal_membership(checker: &mut Checker, compare: &ast::ExprCompa
         return;
     };
 
-    if !matches!(right, Expr::List(_) | Expr::Tuple(_)) {
+    let elts = match right {
+        Expr::List(ast::ExprList { elts, .. }) => elts,
+        Expr::Tuple(ast::ExprTuple { elts, .. }) => elts,
+        _ => return,
+    };
+
+    // If `left`, or any of the elements in `right`, are known to _not_ be hashable, return.
+    if std::iter::once(compare.left.as_ref())
+        .chain(elts)
+        .any(|expr| match expr {
+            // Expressions that are known _not_ to be hashable.
+            Expr::List(_)
+            | Expr::Set(_)
+            | Expr::Dict(_)
+            | Expr::ListComp(_)
+            | Expr::SetComp(_)
+            | Expr::DictComp(_)
+            | Expr::GeneratorExp(_)
+            | Expr::Await(_)
+            | Expr::Yield(_)
+            | Expr::YieldFrom(_) => true,
+            // Expressions that can be _inferred_ not to be hashable.
+            Expr::Name(name) => {
+                let Some(id) = checker.semantic().resolve_name(name) else {
+                    return false;
+                };
+                let binding = checker.semantic().binding(id);
+                typing::is_list(binding, checker.semantic())
+                    || typing::is_dict(binding, checker.semantic())
+                    || typing::is_set(binding, checker.semantic())
+            }
+            _ => false,
+        })
+    {
         return;
     }
 

crates/ruff_linter/src/rules/pylint/rules/magic_value_comparison.rs

@@ -86,8 +86,10 @@ fn is_magic_value(literal_expr: LiteralExpressionRef, allowed_types: &[ConstantT
             !matches!(value.to_str(), "" | "__main__")
         }
         LiteralExpressionRef::NumberLiteral(ast::ExprNumberLiteral { value, .. }) => match value {
+            #[allow(clippy::float_cmp)]
+            ast::Number::Float(value) => !(*value == 0.0 || *value == 1.0),
             ast::Number::Int(value) => !matches!(*value, Int::ZERO | Int::ONE),
-            _ => true,
+            ast::Number::Complex { .. } => true,
         },
         LiteralExpressionRef::BytesLiteral(_) => true,
     }

crates/ruff_linter/src/rules/pylint/rules/non_ascii_name.rs

@@ -52,6 +52,7 @@ pub(crate) fn non_ascii_name(binding: &Binding, locator: &Locator) -> Option<Dia
         BindingKind::Assignment => Kind::Assignment,
         BindingKind::TypeParam => Kind::TypeParam,
         BindingKind::LoopVar => Kind::LoopVar,
+        BindingKind::ComprehensionVar => Kind::ComprenhensionVar,
         BindingKind::WithItemVar => Kind::WithItemVar,
         BindingKind::Global => Kind::Global,
         BindingKind::Nonlocal(_) => Kind::Nonlocal,
@@ -88,6 +89,7 @@ enum Kind {
     Assignment,
     TypeParam,
     LoopVar,
+    ComprenhensionVar,
     WithItemVar,
     Global,
     Nonlocal,
@@ -105,6 +107,7 @@ impl fmt::Display for Kind {
             Kind::Assignment => f.write_str("Variable"),
             Kind::TypeParam => f.write_str("Type parameter"),
             Kind::LoopVar => f.write_str("Variable"),
+            Kind::ComprenhensionVar => f.write_str("Variable"),
             Kind::WithItemVar => f.write_str("Variable"),
             Kind::Global => f.write_str("Global"),
             Kind::Nonlocal => f.write_str("Nonlocal"),

crates/ruff_linter/src/rules/pylint/snapshots/ruff_linter__rules__pylint__tests__PLR2004_magic_value_comparison.py.snap

@@ -10,49 +10,67 @@ magic_value_comparison.py:5:4: PLR2004 Magic value used in comparison, consider
 6 |     pass
   |
 
-magic_value_comparison.py:38:12: PLR2004 Magic value used in comparison, consider replacing `2` with a constant variable
+magic_value_comparison.py:47:12: PLR2004 Magic value used in comparison, consider replacing `2` with a constant variable
    |
-36 |     pass
-37 | 
-38 | if argc != 2:  # [magic-value-comparison]
-   |            ^ PLR2004
-39 |     pass
-   |
-
-magic_value_comparison.py:41:12: PLR2004 Magic value used in comparison, consider replacing `-2` with a constant variable
-   |
-39 |     pass
-40 | 
-41 | if argc != -2:  # [magic-value-comparison]
-   |            ^^ PLR2004
-42 |     pass
-   |
-
-magic_value_comparison.py:44:12: PLR2004 Magic value used in comparison, consider replacing `+2` with a constant variable
-   |
-42 |     pass
-43 | 
-44 | if argc != +2:  # [magic-value-comparison]
-   |            ^^ PLR2004
 45 |     pass
+46 | 
+47 | if argc != 2:  # [magic-value-comparison]
+   |            ^ PLR2004
+48 |     pass
    |
 
-magic_value_comparison.py:65:21: PLR2004 Magic value used in comparison, consider replacing `3.141592653589793238` with a constant variable
+magic_value_comparison.py:50:12: PLR2004 Magic value used in comparison, consider replacing `-2` with a constant variable
    |
-63 | pi_estimation = 3.14
-64 | 
-65 | if pi_estimation == 3.141592653589793238:  # [magic-value-comparison]
+48 |     pass
+49 | 
+50 | if argc != -2:  # [magic-value-comparison]
+   |            ^^ PLR2004
+51 |     pass
+   |
+
+magic_value_comparison.py:53:12: PLR2004 Magic value used in comparison, consider replacing `+2` with a constant variable
+   |
+51 |     pass
+52 | 
+53 | if argc != +2:  # [magic-value-comparison]
+   |            ^^ PLR2004
+54 |     pass
+   |
+
+magic_value_comparison.py:56:12: PLR2004 Magic value used in comparison, consider replacing `-2.0` with a constant variable
+   |
+54 |     pass
+55 | 
+56 | if argc != -2.0:  # [magic-value-comparison]
+   |            ^^^^ PLR2004
+57 |     pass
+   |
+
+magic_value_comparison.py:59:12: PLR2004 Magic value used in comparison, consider replacing `+2.0` with a constant variable
+   |
+57 |     pass
+58 | 
+59 | if argc != +2.0:  # [magic-value-comparison]
+   |            ^^^^ PLR2004
+60 |     pass
+   |
+
+magic_value_comparison.py:80:21: PLR2004 Magic value used in comparison, consider replacing `3.141592653589793238` with a constant variable
+   |
+78 | pi_estimation = 3.14
+79 | 
+80 | if pi_estimation == 3.141592653589793238:  # [magic-value-comparison]
    |                     ^^^^^^^^^^^^^^^^^^^^ PLR2004
-66 |     pass
+81 |     pass
    |
 
-magic_value_comparison.py:71:21: PLR2004 Magic value used in comparison, consider replacing `0x3` with a constant variable
+magic_value_comparison.py:86:21: PLR2004 Magic value used in comparison, consider replacing `0x3` with a constant variable
    |
-69 |     pass
-70 | 
-71 | if pi_estimation == 0x3:  # [magic-value-comparison]
+84 |     pass
+85 | 
+86 | if pi_estimation == 0x3:  # [magic-value-comparison]
    |                     ^^^ PLR2004
-72 |     pass
+87 |     pass
    |
 
 

crates/ruff_linter/src/rules/pylint/snapshots/ruff_linter__rules__pylint__tests__PLR6201_literal_membership.py.snap

@@ -48,8 +48,8 @@ literal_membership.py:4:6: PLR6201 [*] Use a `set` literal when testing for memb
 5 | |     1, 2, 3
 6 | | )
   | |_^ PLR6201
-7 |   
-8 |   # OK
+7 |   fruits = ["cherry", "grapes"]
+8 |   "cherry" in fruits
   |
   = help: Convert to `set`
 
@@ -62,8 +62,29 @@ literal_membership.py:4:6: PLR6201 [*] Use a `set` literal when testing for memb
 5 5 |     1, 2, 3
 6   |-)
   6 |+}
-7 7 | 
-8 8 | # OK
-9 9 | fruits = ["cherry", "grapes"]
+7 7 | fruits = ["cherry", "grapes"]
+8 8 | "cherry" in fruits
+9 9 | _ = {key: value for key, value in {"a": 1, "b": 2}.items() if key in ("a", "b")}
+
+literal_membership.py:9:70: PLR6201 [*] Use a `set` literal when testing for membership
+   |
+ 7 | fruits = ["cherry", "grapes"]
+ 8 | "cherry" in fruits
+ 9 | _ = {key: value for key, value in {"a": 1, "b": 2}.items() if key in ("a", "b")}
+   |                                                                      ^^^^^^^^^^ PLR6201
+10 | 
+11 | # OK
+   |
+   = help: Convert to `set`
+
+ℹ Unsafe fix
+6  6  | )
+7  7  | fruits = ["cherry", "grapes"]
+8  8  | "cherry" in fruits
+9     |-_ = {key: value for key, value in {"a": 1, "b": 2}.items() if key in ("a", "b")}
+   9  |+_ = {key: value for key, value in {"a": 1, "b": 2}.items() if key in {"a", "b"}}
+10 10 | 
+11 11 | # OK
+12 12 | fruits in [[1, 2, 3], [4, 5, 6]]
 
 

crates/ruff_linter/src/rules/pylint/snapshots/ruff_linter__rules__pylint__tests__allow_magic_value_types.snap

@@ -1,31 +1,49 @@
 ---
 source: crates/ruff_linter/src/rules/pylint/mod.rs
 ---
-magic_value_comparison.py:59:22: PLR2004 Magic value used in comparison, consider replacing `"Hunter2"` with a constant variable
+magic_value_comparison.py:56:12: PLR2004 Magic value used in comparison, consider replacing `-2.0` with a constant variable
+   |
+54 |     pass
+55 | 
+56 | if argc != -2.0:  # [magic-value-comparison]
+   |            ^^^^ PLR2004
+57 |     pass
+   |
+
+magic_value_comparison.py:59:12: PLR2004 Magic value used in comparison, consider replacing `+2.0` with a constant variable
    |
 57 |     pass
 58 | 
-59 | if input_password == "Hunter2":  # correct
-   |                      ^^^^^^^^^ PLR2004
+59 | if argc != +2.0:  # [magic-value-comparison]
+   |            ^^^^ PLR2004
 60 |     pass
    |
 
-magic_value_comparison.py:65:21: PLR2004 Magic value used in comparison, consider replacing `3.141592653589793238` with a constant variable
+magic_value_comparison.py:74:22: PLR2004 Magic value used in comparison, consider replacing `"Hunter2"` with a constant variable
    |
-63 | pi_estimation = 3.14
-64 | 
-65 | if pi_estimation == 3.141592653589793238:  # [magic-value-comparison]
+72 |     pass
+73 | 
+74 | if input_password == "Hunter2":  # correct
+   |                      ^^^^^^^^^ PLR2004
+75 |     pass
+   |
+
+magic_value_comparison.py:80:21: PLR2004 Magic value used in comparison, consider replacing `3.141592653589793238` with a constant variable
+   |
+78 | pi_estimation = 3.14
+79 | 
+80 | if pi_estimation == 3.141592653589793238:  # [magic-value-comparison]
    |                     ^^^^^^^^^^^^^^^^^^^^ PLR2004
-66 |     pass
+81 |     pass
    |
 
-magic_value_comparison.py:77:18: PLR2004 Magic value used in comparison, consider replacing `b"something"` with a constant variable
+magic_value_comparison.py:92:18: PLR2004 Magic value used in comparison, consider replacing `b"something"` with a constant variable
    |
-75 | user_input = b"Hello, There!"
-76 | 
-77 | if user_input == b"something":  # correct
+90 | user_input = b"Hello, There!"
+91 | 
+92 | if user_input == b"something":  # correct
    |                  ^^^^^^^^^^^^ PLR2004
-78 |     pass
+93 |     pass
    |
 
 

crates/ruff_linter/src/rules/refurb/mod.rs

@@ -17,6 +17,7 @@ mod tests {
     #[test_case(Rule::ReadWholeFile, Path::new("FURB101.py"))]
     #[test_case(Rule::RepeatedAppend, Path::new("FURB113.py"))]
     #[test_case(Rule::ReimplementedOperator, Path::new("FURB118.py"))]
+    #[test_case(Rule::ReadlinesInFor, Path::new("FURB129.py"))]
     #[test_case(Rule::DeleteFullSlice, Path::new("FURB131.py"))]
     #[test_case(Rule::CheckAndRemoveFromSet, Path::new("FURB132.py"))]
     #[test_case(Rule::IfExprMinMax, Path::new("FURB136.py"))]

crates/ruff_linter/src/rules/refurb/rules/mod.rs

@@ -9,6 +9,7 @@ pub(crate) use math_constant::*;
 pub(crate) use metaclass_abcmeta::*;
 pub(crate) use print_empty_string::*;
 pub(crate) use read_whole_file::*;
+pub(crate) use readlines_in_for::*;
 pub(crate) use redundant_log_base::*;
 pub(crate) use regex_flag_alias::*;
 pub(crate) use reimplemented_operator::*;
@@ -30,6 +31,7 @@ mod math_constant;
 mod metaclass_abcmeta;
 mod print_empty_string;
 mod read_whole_file;
+mod readlines_in_for;
 mod redundant_log_base;
 mod regex_flag_alias;
 mod reimplemented_operator;

crates/ruff_linter/src/rules/refurb/rules/readlines_in_for.rs

@@ -0,0 +1,92 @@
+use ruff_diagnostics::{AlwaysFixableViolation, Diagnostic, Edit, Fix};
+use ruff_macros::{derive_message_formats, violation};
+use ruff_python_ast::{Comprehension, Expr, StmtFor};
+use ruff_python_semantic::analyze::typing;
+use ruff_python_semantic::analyze::typing::is_io_base_expr;
+use ruff_text_size::Ranged;
+
+use crate::checkers::ast::Checker;
+
+/// ## What it does
+/// Checks for uses of `readlines()` when iterating over a file line-by-line.
+///
+/// ## Why is this bad?
+/// Rather than iterating over all lines in a file by calling `readlines()`,
+/// it's more convenient and performant to iterate over the file object
+/// directly.
+///
+/// ## Example
+/// ```python
+/// with open("file.txt") as fp:
+///     for line in fp.readlines():
+///         ...
+/// ```
+///
+/// Use instead:
+/// ```python
+/// with open("file.txt") as fp:
+///     for line in fp:
+///         ...
+/// ```
+///
+/// ## References
+/// - [Python documentation: `io.IOBase.readlines`](https://docs.python.org/3/library/io.html#io.IOBase.readlines)
+#[violation]
+pub(crate) struct ReadlinesInFor;
+
+impl AlwaysFixableViolation for ReadlinesInFor {
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        format!("Instead of calling `readlines()`, iterate over file object directly")
+    }
+
+    fn fix_title(&self) -> String {
+        "Remove `readlines()`".into()
+    }
+}
+
+/// FURB129
+pub(crate) fn readlines_in_for(checker: &mut Checker, for_stmt: &StmtFor) {
+    readlines_in_iter(checker, for_stmt.iter.as_ref());
+}
+
+/// FURB129
+pub(crate) fn readlines_in_comprehension(checker: &mut Checker, comprehension: &Comprehension) {
+    readlines_in_iter(checker, &comprehension.iter);
+}
+
+fn readlines_in_iter(checker: &mut Checker, iter_expr: &Expr) {
+    let Expr::Call(expr_call) = iter_expr else {
+        return;
+    };
+
+    let Expr::Attribute(expr_attr) = expr_call.func.as_ref() else {
+        return;
+    };
+
+    if expr_attr.attr.as_str() != "readlines" || !expr_call.arguments.is_empty() {
+        return;
+    }
+
+    // Determine whether `fp` in `fp.readlines()` was bound to a file object.
+    if let Expr::Name(name) = expr_attr.value.as_ref() {
+        if !checker
+            .semantic()
+            .resolve_name(name)
+            .map(|id| checker.semantic().binding(id))
+            .is_some_and(|binding| typing::is_io_base(binding, checker.semantic()))
+        {
+            return;
+        }
+    } else {
+        if !is_io_base_expr(expr_attr.value.as_ref(), checker.semantic()) {
+            return;
+        }
+    }
+
+    let mut diagnostic = Diagnostic::new(ReadlinesInFor, expr_call.range());
+    diagnostic.set_fix(Fix::unsafe_edit(Edit::range_deletion(
+        expr_call.range().add_start(expr_attr.value.range().len()),
+    )));
+    checker.diagnostics.push(diagnostic);
+}

crates/ruff_linter/src/rules/refurb/snapshots/ruff_linter__rules__refurb__tests__FURB129_FURB129.py.snap

@@ -0,0 +1,207 @@
+---
+source: crates/ruff_linter/src/rules/refurb/mod.rs
+---
+FURB129.py:7:18: FURB129 [*] Instead of calling `readlines()`, iterate over file object directly
+  |
+5 | # Errors
+6 | with open("FURB129.py") as f:
+7 |     for _line in f.readlines():
+  |                  ^^^^^^^^^^^^^ FURB129
+8 |         pass
+9 |     a = [line.lower() for line in f.readlines()]
+  |
+  = help: Remove `readlines()`
+
+ℹ Unsafe fix
+4 4 | 
+5 5 | # Errors
+6 6 | with open("FURB129.py") as f:
+7   |-    for _line in f.readlines():
+  7 |+    for _line in f:
+8 8 |         pass
+9 9 |     a = [line.lower() for line in f.readlines()]
+10 10 |     b = {line.upper() for line in f.readlines()}
+
+FURB129.py:9:35: FURB129 [*] Instead of calling `readlines()`, iterate over file object directly
+   |
+ 7 |     for _line in f.readlines():
+ 8 |         pass
+ 9 |     a = [line.lower() for line in f.readlines()]
+   |                                   ^^^^^^^^^^^^^ FURB129
+10 |     b = {line.upper() for line in f.readlines()}
+11 |     c = {line.lower(): line.upper() for line in f.readlines()}
+   |
+   = help: Remove `readlines()`
+
+ℹ Unsafe fix
+6  6  | with open("FURB129.py") as f:
+7  7  |     for _line in f.readlines():
+8  8  |         pass
+9     |-    a = [line.lower() for line in f.readlines()]
+   9  |+    a = [line.lower() for line in f]
+10 10 |     b = {line.upper() for line in f.readlines()}
+11 11 |     c = {line.lower(): line.upper() for line in f.readlines()}
+12 12 | 
+
+FURB129.py:10:35: FURB129 [*] Instead of calling `readlines()`, iterate over file object directly
+   |
+ 8 |         pass
+ 9 |     a = [line.lower() for line in f.readlines()]
+10 |     b = {line.upper() for line in f.readlines()}
+   |                                   ^^^^^^^^^^^^^ FURB129
+11 |     c = {line.lower(): line.upper() for line in f.readlines()}
+   |
+   = help: Remove `readlines()`
+
+ℹ Unsafe fix
+7  7  |     for _line in f.readlines():
+8  8  |         pass
+9  9  |     a = [line.lower() for line in f.readlines()]
+10    |-    b = {line.upper() for line in f.readlines()}
+   10 |+    b = {line.upper() for line in f}
+11 11 |     c = {line.lower(): line.upper() for line in f.readlines()}
+12 12 | 
+13 13 | with Path("FURB129.py").open() as f:
+
+FURB129.py:11:49: FURB129 [*] Instead of calling `readlines()`, iterate over file object directly
+   |
+ 9 |     a = [line.lower() for line in f.readlines()]
+10 |     b = {line.upper() for line in f.readlines()}
+11 |     c = {line.lower(): line.upper() for line in f.readlines()}
+   |                                                 ^^^^^^^^^^^^^ FURB129
+12 | 
+13 | with Path("FURB129.py").open() as f:
+   |
+   = help: Remove `readlines()`
+
+ℹ Unsafe fix
+8  8  |         pass
+9  9  |     a = [line.lower() for line in f.readlines()]
+10 10 |     b = {line.upper() for line in f.readlines()}
+11    |-    c = {line.lower(): line.upper() for line in f.readlines()}
+   11 |+    c = {line.lower(): line.upper() for line in f}
+12 12 | 
+13 13 | with Path("FURB129.py").open() as f:
+14 14 |     for _line in f.readlines():
+
+FURB129.py:14:18: FURB129 [*] Instead of calling `readlines()`, iterate over file object directly
+   |
+13 | with Path("FURB129.py").open() as f:
+14 |     for _line in f.readlines():
+   |                  ^^^^^^^^^^^^^ FURB129
+15 |         pass
+   |
+   = help: Remove `readlines()`
+
+ℹ Unsafe fix
+11 11 |     c = {line.lower(): line.upper() for line in f.readlines()}
+12 12 | 
+13 13 | with Path("FURB129.py").open() as f:
+14    |-    for _line in f.readlines():
+   14 |+    for _line in f:
+15 15 |         pass
+16 16 | 
+17 17 | for _line in open("FURB129.py").readlines():
+
+FURB129.py:17:14: FURB129 [*] Instead of calling `readlines()`, iterate over file object directly
+   |
+15 |         pass
+16 | 
+17 | for _line in open("FURB129.py").readlines():
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ FURB129
+18 |     pass
+   |
+   = help: Remove `readlines()`
+
+ℹ Unsafe fix
+14 14 |     for _line in f.readlines():
+15 15 |         pass
+16 16 | 
+17    |-for _line in open("FURB129.py").readlines():
+   17 |+for _line in open("FURB129.py"):
+18 18 |     pass
+19 19 | 
+20 20 | for _line in Path("FURB129.py").open().readlines():
+
+FURB129.py:20:14: FURB129 [*] Instead of calling `readlines()`, iterate over file object directly
+   |
+18 |     pass
+19 | 
+20 | for _line in Path("FURB129.py").open().readlines():
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ FURB129
+21 |     pass
+   |
+   = help: Remove `readlines()`
+
+ℹ Unsafe fix
+17 17 | for _line in open("FURB129.py").readlines():
+18 18 |     pass
+19 19 | 
+20    |-for _line in Path("FURB129.py").open().readlines():
+   20 |+for _line in Path("FURB129.py").open():
+21 21 |     pass
+22 22 | 
+23 23 | 
+
+FURB129.py:26:18: FURB129 [*] Instead of calling `readlines()`, iterate over file object directly
+   |
+24 | def func():
+25 |     f = Path("FURB129.py").open()
+26 |     for _line in f.readlines():
+   |                  ^^^^^^^^^^^^^ FURB129
+27 |         pass
+28 |     f.close()
+   |
+   = help: Remove `readlines()`
+
+ℹ Unsafe fix
+23 23 | 
+24 24 | def func():
+25 25 |     f = Path("FURB129.py").open()
+26    |-    for _line in f.readlines():
+   26 |+    for _line in f:
+27 27 |         pass
+28 28 |     f.close()
+29 29 | 
+
+FURB129.py:32:18: FURB129 [*] Instead of calling `readlines()`, iterate over file object directly
+   |
+31 | def func(f: io.BytesIO):
+32 |     for _line in f.readlines():
+   |                  ^^^^^^^^^^^^^ FURB129
+33 |         pass
+   |
+   = help: Remove `readlines()`
+
+ℹ Unsafe fix
+29 29 | 
+30 30 | 
+31 31 | def func(f: io.BytesIO):
+32    |-    for _line in f.readlines():
+   32 |+    for _line in f:
+33 33 |         pass
+34 34 | 
+35 35 | 
+
+FURB129.py:38:22: FURB129 [*] Instead of calling `readlines()`, iterate over file object directly
+   |
+36 | def func():
+37 |     with (open("FURB129.py") as f, foo as bar):
+38 |         for _line in f.readlines():
+   |                      ^^^^^^^^^^^^^ FURB129
+39 |             pass
+40 |         for _line in bar.readlines():
+   |
+   = help: Remove `readlines()`
+
+ℹ Unsafe fix
+35 35 | 
+36 36 | def func():
+37 37 |     with (open("FURB129.py") as f, foo as bar):
+38    |-        for _line in f.readlines():
+   38 |+        for _line in f:
+39 39 |             pass
+40 40 |         for _line in bar.readlines():
+41 41 |             pass
+
+

crates/ruff_linter/src/rules/ruff/mod.rs

@@ -48,6 +48,7 @@ mod tests {
     #[test_case(Rule::DefaultFactoryKwarg, Path::new("RUF026.py"))]
     #[test_case(Rule::MissingFStringSyntax, Path::new("RUF027_0.py"))]
     #[test_case(Rule::MissingFStringSyntax, Path::new("RUF027_1.py"))]
+    #[test_case(Rule::MissingFStringSyntax, Path::new("RUF027_2.py"))]
     fn rules(rule_code: Rule, path: &Path) -> Result<()> {
         let snapshot = format!("{}_{}", rule_code.noqa_code(), path.to_string_lossy());
         let diagnostics = test_path(

crates/ruff_linter/src/rules/ruff/rules/ambiguous_unicode_character.rs

@@ -4,9 +4,11 @@ use bitflags::bitflags;
 
 use ruff_diagnostics::{Diagnostic, DiagnosticKind, Violation};
 use ruff_macros::{derive_message_formats, violation};
+use ruff_python_ast::StringLike;
 use ruff_source_file::Locator;
-use ruff_text_size::{TextLen, TextRange, TextSize};
+use ruff_text_size::{Ranged, TextLen, TextRange, TextSize};
 
+use crate::checkers::ast::Checker;
 use crate::registry::AsRule;
 use crate::rules::ruff::rules::confusables::confusable;
 use crate::rules::ruff::rules::Context;
@@ -171,16 +173,59 @@ impl Violation for AmbiguousUnicodeCharacterComment {
     }
 }
 
-/// RUF001, RUF002, RUF003
-pub(crate) fn ambiguous_unicode_character(
+/// RUF003
+pub(crate) fn ambiguous_unicode_character_comment(
     diagnostics: &mut Vec<Diagnostic>,
     locator: &Locator,
     range: TextRange,
+    settings: &LinterSettings,
+) {
+    let text = locator.slice(range);
+    ambiguous_unicode_character(diagnostics, text, range, Context::Comment, settings);
+}
+
+/// RUF001, RUF002
+pub(crate) fn ambiguous_unicode_character_string(checker: &mut Checker, string_like: StringLike) {
+    let context = if checker.semantic().in_docstring() {
+        Context::Docstring
+    } else {
+        Context::String
+    };
+
+    match string_like {
+        StringLike::StringLiteral(string_literal) => {
+            for string in &string_literal.value {
+                let text = checker.locator().slice(string);
+                ambiguous_unicode_character(
+                    &mut checker.diagnostics,
+                    text,
+                    string.range(),
+                    context,
+                    checker.settings,
+                );
+            }
+        }
+        StringLike::FStringLiteral(f_string_literal) => {
+            let text = checker.locator().slice(f_string_literal);
+            ambiguous_unicode_character(
+                &mut checker.diagnostics,
+                text,
+                f_string_literal.range(),
+                context,
+                checker.settings,
+            );
+        }
+        StringLike::BytesLiteral(_) => (),
+    }
+}
+
+fn ambiguous_unicode_character(
+    diagnostics: &mut Vec<Diagnostic>,
+    text: &str,
+    range: TextRange,
     context: Context,
     settings: &LinterSettings,
 ) {
-    let text = locator.slice(range);
-
     // Most of the time, we don't need to check for ambiguous unicode characters at all.
     if text.is_ascii() {
         return;

crates/ruff_linter/src/rules/ruff/rules/asyncio_dangling_task.rs

@@ -52,14 +52,15 @@ use ruff_text_size::Ranged;
 /// - [The Python Standard Library](https://docs.python.org/3/library/asyncio-task.html#asyncio.create_task)
 #[violation]
 pub struct AsyncioDanglingTask {
+    expr: String,
     method: Method,
 }
 
 impl Violation for AsyncioDanglingTask {
     #[derive_message_formats]
     fn message(&self) -> String {
-        let AsyncioDanglingTask { method } = self;
-        format!("Store a reference to the return value of `asyncio.{method}`")
+        let AsyncioDanglingTask { expr, method } = self;
+        format!("Store a reference to the return value of `{expr}.{method}`")
     }
 }
 
@@ -80,23 +81,35 @@ pub(crate) fn asyncio_dangling_task(expr: &Expr, semantic: &SemanticModel) -> Op
             })
     {
         return Some(Diagnostic::new(
-            AsyncioDanglingTask { method },
+            AsyncioDanglingTask {
+                expr: "asyncio".to_string(),
+                method,
+            },
             expr.range(),
         ));
     }
 
-    // Ex) `loop = asyncio.get_running_loop(); loop.create_task(...)`
+    // Ex) `loop = ...; loop.create_task(...)`
     if let Expr::Attribute(ast::ExprAttribute { attr, value, .. }) = func.as_ref() {
         if attr == "create_task" {
-            if typing::resolve_assignment(value, semantic).is_some_and(|call_path| {
-                matches!(call_path.as_slice(), ["asyncio", "get_running_loop"])
-            }) {
-                return Some(Diagnostic::new(
-                    AsyncioDanglingTask {
-                        method: Method::CreateTask,
-                    },
-                    expr.range(),
-                ));
+            if let Expr::Name(name) = value.as_ref() {
+                if typing::resolve_assignment(value, semantic).is_some_and(|call_path| {
+                    matches!(
+                        call_path.as_slice(),
+                        [
+                            "asyncio",
+                            "get_event_loop" | "get_running_loop" | "new_event_loop"
+                        ]
+                    )
+                }) {
+                    return Some(Diagnostic::new(
+                        AsyncioDanglingTask {
+                            expr: name.id.to_string(),
+                            method: Method::CreateTask,
+                        },
+                        expr.range(),
+                    ));
+                }
             }
         }
     }

crates/ruff_linter/src/rules/ruff/rules/missing_fstring_syntax.rs

@@ -88,8 +88,10 @@ fn should_be_fstring(
         return false;
     }
 
-    let Ok(ast::Expr::FString(ast::ExprFString { value, .. })) =
-        parse_expression(&format!("f{}", locator.slice(literal.range())))
+    let fstring_expr = format!("f{}", locator.slice(literal));
+
+    // Note: Range offsets for `value` are based on `fstring_expr`
+    let Ok(ast::Expr::FString(ast::ExprFString { value, .. })) = parse_expression(&fstring_expr)
     else {
         return false;
     };
@@ -159,7 +161,7 @@ fn should_be_fstring(
                 has_name = true;
             }
             if let Some(spec) = &element.format_spec {
-                let spec = locator.slice(spec.range());
+                let spec = &fstring_expr[spec.range()];
                 if FormatSpec::parse(spec).is_err() {
                     return false;
                 }

crates/ruff_linter/src/rules/ruff/rules/sequence_sorting.rs

@@ -895,6 +895,27 @@ fn multiline_string_sequence_postlude<'a>(
     };
     let postlude = locator.slice(TextRange::new(postlude_start, dunder_all_range_end));
 
+    // If the postlude consists solely of a closing parenthesis
+    // (not preceded by any whitespace/newlines),
+    // plus possibly a single trailing comma prior to the parenthesis,
+    // fixup the postlude so that the parenthesis appears on its own line,
+    // and so that the final item has a trailing comma.
+    // This produces formatting more similar
+    // to that which the formatter would produce.
+    if postlude.len() <= 2 {
+        let mut reversed_postlude_chars = postlude.chars().rev();
+        if let Some(closing_paren @ (')' | '}' | ']')) = reversed_postlude_chars.next() {
+            if reversed_postlude_chars.next().map_or(true, |c| c == ',') {
+                return Cow::Owned(format!(",{newline}{leading_indent}{closing_paren}"));
+            }
+        }
+    }
+
+    let newline_chars = ['\r', '\n'];
+    if !postlude.starts_with(newline_chars) {
+        return Cow::Borrowed(postlude);
+    }
+
     // The rest of this function uses heuristics to
     // avoid very long indents for the closing paren
     // that don't match the style for the rest of the
@@ -920,10 +941,6 @@ fn multiline_string_sequence_postlude<'a>(
     //     "y",
     //            ]
     // ```
-    let newline_chars = ['\r', '\n'];
-    if !postlude.starts_with(newline_chars) {
-        return Cow::Borrowed(postlude);
-    }
     if TextSize::of(leading_indentation(
         postlude.trim_start_matches(newline_chars),
     )) <= TextSize::of(item_indent)
@@ -931,7 +948,7 @@ fn multiline_string_sequence_postlude<'a>(
         return Cow::Borrowed(postlude);
     }
     let trimmed_postlude = postlude.trim_start();
-    if trimmed_postlude.starts_with([']', ')']) {
+    if trimmed_postlude.starts_with([']', ')', '}']) {
         return Cow::Owned(format!("{newline}{leading_indent}{trimmed_postlude}"));
     }
     Cow::Borrowed(postlude)

crates/ruff_linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__RUF006_RUF006.py.snap

@@ -25,7 +25,7 @@ RUF006.py:68:12: RUF006 Store a reference to the return value of `asyncio.create
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ RUF006
    |
 
-RUF006.py:74:26: RUF006 Store a reference to the return value of `asyncio.create_task`
+RUF006.py:74:26: RUF006 Store a reference to the return value of `loop.create_task`
    |
 72 | def f():
 73 |     loop = asyncio.get_running_loop()
@@ -33,7 +33,7 @@ RUF006.py:74:26: RUF006 Store a reference to the return value of `asyncio.create
    |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ RUF006
    |
 
-RUF006.py:97:5: RUF006 Store a reference to the return value of `asyncio.create_task`
+RUF006.py:97:5: RUF006 Store a reference to the return value of `loop.create_task`
    |
 95 | def f():
 96 |     loop = asyncio.get_running_loop()
@@ -41,4 +41,24 @@ RUF006.py:97:5: RUF006 Store a reference to the return value of `asyncio.create_
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ RUF006
    |
 
+RUF006.py:170:5: RUF006 Store a reference to the return value of `loop.create_task`
+    |
+168 | def f():
+169 |     loop = asyncio.new_event_loop()
+170 |     loop.create_task(main()) # Error
+    |     ^^^^^^^^^^^^^^^^^^^^^^^^ RUF006
+171 | 
+172 | # Error
+    |
+
+RUF006.py:175:5: RUF006 Store a reference to the return value of `loop.create_task`
+    |
+173 | def f():
+174 |     loop = asyncio.get_event_loop()
+175 |     loop.create_task(main()) # Error
+    |     ^^^^^^^^^^^^^^^^^^^^^^^^ RUF006
+176 | 
+177 | # OK
+    |
+
 

crates/ruff_linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__RUF022_RUF022.py.snap

@@ -386,18 +386,24 @@ RUF022.py:54:11: RUF022 [*] `__all__` is not sorted
 76 70 |     "SUNDAY",
 77 71 |     "THURSDAY",
 78 72 |     "TUESDAY",
-   73 |+    "WEDNESDAY",
+79    |-    "TextCalendar",
+80 73 |     "WEDNESDAY",
    74 |+    "Calendar",
    75 |+    "Day",
    76 |+    "HTMLCalendar",
    77 |+    "IllegalMonthError",
    78 |+    "LocaleHTMLCalendar",
    79 |+    "Month",
-79 80 |     "TextCalendar",
-80    |-    "WEDNESDAY",
+   80 |+    "TextCalendar",
 81 81 |     "calendar",
 82 82 |     "timegm",
 83 83 |     "weekday",
+84    |-    "weekheader"]
+   84 |+    "weekheader",
+   85 |+]
+85 86 | 
+86 87 | ##########################################
+87 88 | # Messier multiline __all__ definitions...
 
 RUF022.py:91:11: RUF022 [*] `__all__` is not sorted
    |
@@ -559,10 +565,11 @@ RUF022.py:110:11: RUF022 [*] `__all__` is not sorted
     151 |+    "register_error",
     152 |+    "replace_errors",
     153 |+    "strict_errors",
-    154 |+    "xmlcharrefreplace_errors"]
-124 155 | 
-125 156 | __all__: tuple[str, ...] = (  # a comment about the opening paren
-126 157 |     # multiline comment about "bbb" part 1
+    154 |+    "xmlcharrefreplace_errors",
+    155 |+]
+124 156 | 
+125 157 | __all__: tuple[str, ...] = (  # a comment about the opening paren
+126 158 |     # multiline comment about "bbb" part 1
 
 RUF022.py:125:28: RUF022 [*] `__all__` is not sorted
     |
@@ -918,13 +925,13 @@ RUF022.py:225:11: RUF022 [*] `__all__` is not sorted
 223 223 | ############################################################
 224 224 | 
 225 225 | __all__ = (
-226     |-    "loads",
-227     |-    "dumps",)
     226 |+    "dumps",
-    227 |+    "loads",)
-228 228 | 
-229 229 | __all__ = [
-230 230 |     "loads",
+226 227 |     "loads",
+227     |-    "dumps",)
+    228 |+)
+228 229 | 
+229 230 | __all__ = [
+230 231 |     "loads",
 
 RUF022.py:229:11: RUF022 [*] `__all__` is not sorted
     |
@@ -1002,7 +1009,7 @@ RUF022.py:243:11: RUF022 [*] `__all__` is not sorted
 251 | | )
     | |_^ RUF022
 252 |   
-253 |   ###################################
+253 |   __all__ = (  # comment about the opening paren
     |
     = help: Apply an isort-style sorting to `__all__`
 
@@ -1021,4 +1028,53 @@ RUF022.py:243:11: RUF022 [*] `__all__` is not sorted
 250 249 |     ,
 251 250 | )
 
+RUF022.py:253:11: RUF022 [*] `__all__` is not sorted
+    |
+251 |   )
+252 |   
+253 |   __all__ = (  # comment about the opening paren
+    |  ___________^
+254 | |     # multiline strange comment 0a
+255 | |     # multiline strange comment 0b
+256 | |     "foo"  # inline comment about foo
+257 | |     # multiline strange comment 1a
+258 | |     # multiline strange comment 1b
+259 | |     ,  # comment about the comma??
+260 | |     # comment about bar part a
+261 | |     # comment about bar part b
+262 | |     "bar"  # inline comment about bar
+263 | |     # strange multiline comment comment 2a
+264 | |     # strange multiline comment 2b
+265 | |     ,
+266 | |     # strange multiline comment 3a
+267 | |     # strange multiline comment 3b
+268 | | )  # comment about the closing paren
+    | |_^ RUF022
+269 |   
+270 |   ###################################
+    |
+    = help: Apply an isort-style sorting to `__all__`
+
+ℹ Safe fix
+251 251 | )
+252 252 | 
+253 253 | __all__ = (  # comment about the opening paren
+254     |-    # multiline strange comment 0a
+255     |-    # multiline strange comment 0b
+256     |-    "foo"  # inline comment about foo
+257 254 |     # multiline strange comment 1a
+258 255 |     # multiline strange comment 1b
+259     |-    ,  # comment about the comma??
+    256 |+      # comment about the comma??
+260 257 |     # comment about bar part a
+261 258 |     # comment about bar part b
+262     |-    "bar"  # inline comment about bar
+    259 |+    "bar",  # inline comment about bar
+    260 |+    # multiline strange comment 0a
+    261 |+    # multiline strange comment 0b
+    262 |+    "foo"  # inline comment about foo
+263 263 |     # strange multiline comment comment 2a
+264 264 |     # strange multiline comment 2b
+265 265 |     ,
+
 

crates/ruff_linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__RUF023_RUF023.py.snap

@@ -564,10 +564,11 @@ RUF023.py:162:17: RUF023 [*] `BezierBuilder.__slots__` is not sorted
     162 |+    __slots__ = (
     163 |+        'canvas',
     164 |+        'xp',
-    165 |+        'yp',)
-164 166 | 
-165 167 | class BezierBuilder2:
-166 168 |     __slots__ = {'xp', 'yp',
+    165 |+        'yp',
+    166 |+    )
+164 167 | 
+165 168 | class BezierBuilder2:
+166 169 |     __slots__ = {'xp', 'yp',
 
 RUF023.py:166:17: RUF023 [*] `BezierBuilder2.__slots__` is not sorted
     |
@@ -643,7 +644,7 @@ RUF023.py:181:17: RUF023 [*] `BezierBuilder4.__slots__` is not sorted
 189 | |     )
     | |_____^ RUF023
 190 |   
-191 |   ###################################
+191 |       __slots__ = {"foo", "bar",
     |
     = help: Apply a natural sort to `BezierBuilder4.__slots__`
 
@@ -662,4 +663,35 @@ RUF023.py:181:17: RUF023 [*] `BezierBuilder4.__slots__` is not sorted
 188 187 |         ,
 189 188 |     )
 
+RUF023.py:191:17: RUF023 [*] `BezierBuilder4.__slots__` is not sorted
+    |
+189 |       )
+190 |   
+191 |       __slots__ = {"foo", "bar",
+    |  _________________^
+192 | |                  "baz", "bingo"
+193 | |                  }
+    | |__________________^ RUF023
+194 |   
+195 |   ###################################
+    |
+    = help: Apply a natural sort to `BezierBuilder4.__slots__`
+
+ℹ Safe fix
+188 188 |         ,
+189 189 |     )
+190 190 | 
+191     |-    __slots__ = {"foo", "bar",
+192     |-                 "baz", "bingo"
+193     |-                 }
+    191 |+    __slots__ = {
+    192 |+        "bar",
+    193 |+        "baz",
+    194 |+        "bingo",
+    195 |+        "foo"
+    196 |+    }
+194 197 | 
+195 198 | ###################################
+196 199 | # These should all not get flagged:
+
 

crates/ruff_linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__RUF027_RUF027_0.py.snap

@@ -285,6 +285,8 @@ RUF027_0.py:70:18: RUF027 [*] Possible f-string without an `f` prefix
 69 |     last = "Appleseed"
 70 |     value.method("{first} {last}")  # RUF027
    |                  ^^^^^^^^^^^^^^^^ RUF027
+71 | 
+72 | def format_specifiers():
    |
    = help: Add `f` prefix
 
@@ -294,5 +296,24 @@ RUF027_0.py:70:18: RUF027 [*] Possible f-string without an `f` prefix
 69 69 |     last = "Appleseed"
 70    |-    value.method("{first} {last}")  # RUF027
    70 |+    value.method(f"{first} {last}")  # RUF027
+71 71 | 
+72 72 | def format_specifiers():
+73 73 |     a = 4
+
+RUF027_0.py:74:9: RUF027 [*] Possible f-string without an `f` prefix
+   |
+72 | def format_specifiers():
+73 |     a = 4
+74 |     b = "{a:b} {a:^5}"
+   |         ^^^^^^^^^^^^^^ RUF027
+   |
+   = help: Add `f` prefix
+
+ℹ Unsafe fix
+71 71 | 
+72 72 | def format_specifiers():
+73 73 |     a = 4
+74    |-    b = "{a:b} {a:^5}"
+   74 |+    b = f"{a:b} {a:^5}"
 
 

crates/ruff_linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__RUF027_RUF027_2.py.snap

@@ -0,0 +1,4 @@
+---
+source: crates/ruff_linter/src/rules/ruff/mod.rs
+---
+

crates/ruff_linter/src/settings/types.rs

@@ -534,7 +534,7 @@ impl SerializationFormat {
     }
 }
 
-#[derive(Debug, PartialEq, Eq, Serialize, Deserialize, Hash)]
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize, Hash)]
 #[serde(try_from = "String")]
 #[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
 pub struct Version(String);

crates/ruff_macros/src/lib.rs

@@ -92,7 +92,9 @@ pub fn derive_message_formats(_attr: TokenStream, item: TokenStream) -> TokenStr
 ///
 /// Good:
 ///
-/// ```rust
+/// ```ignroe
+/// use ruff_macros::newtype_index;
+///
 /// #[newtype_index]
 /// #[derive(Ord, PartialOrd)]
 /// struct MyIndex;

crates/ruff_notebook/Cargo.toml

@@ -11,6 +11,7 @@ repository = { workspace = true }
 license = { workspace = true }
 
 [lib]
+doctest = false
 
 [dependencies]
 ruff_diagnostics = { path = "../ruff_diagnostics" }

crates/ruff_python_ast/src/comparable.rs

@@ -644,7 +644,7 @@ pub struct ComparableBytesLiteral<'a> {
 impl<'a> From<&'a ast::BytesLiteral> for ComparableBytesLiteral<'a> {
     fn from(bytes_literal: &'a ast::BytesLiteral) -> Self {
         Self {
-            value: bytes_literal.value.as_slice(),
+            value: &bytes_literal.value,
         }
     }
 }

crates/ruff_python_ast/src/helpers.rs

@@ -935,7 +935,7 @@ where
     }
 }
 
-/// A [`StatementVisitor`] that collects all `return` statements in a function or method.
+/// A [`Visitor`] that collects all `return` statements in a function or method.
 #[derive(Default)]
 pub struct ReturnStatementVisitor<'a> {
     pub returns: Vec<&'a ast::StmtReturn>,

crates/ruff_python_ast/src/nodes.rs

@@ -949,7 +949,7 @@ impl Ranged for FStringExpressionElement {
 #[derive(Clone, Debug, PartialEq)]
 pub struct FStringLiteralElement {
     pub range: TextRange,
-    pub value: String,
+    pub value: Box<str>,
 }
 
 impl Ranged for FStringLiteralElement {
@@ -962,7 +962,7 @@ impl Deref for FStringLiteralElement {
     type Target = str;
 
     fn deref(&self) -> &Self::Target {
-        self.value.as_str()
+        &self.value
     }
 }
 
@@ -1011,7 +1011,7 @@ pub struct DebugText {
 #[derive(Clone, Debug, PartialEq)]
 pub struct ExprFString {
     pub range: TextRange,
-    pub value: FStringValue,
+    inner: ExprFStringInner,
 }
 
 impl From<ExprFString> for Expr {
@@ -1020,17 +1020,12 @@ impl From<ExprFString> for Expr {
     }
 }
 
-/// The value representing an [`ExprFString`].
-#[derive(Clone, Debug, PartialEq)]
-pub struct FStringValue {
-    inner: FStringValueInner,
-}
-
-impl FStringValue {
+impl ExprFString {
     /// Creates a new f-string with the given value.
     pub fn single(value: FString) -> Self {
         Self {
-            inner: FStringValueInner::Single(FStringPart::FString(value)),
+            range: value.range,
+            inner: ExprFStringInner::Single(FStringPart::FString(value)),
         }
     }
 
@@ -1040,31 +1035,32 @@ impl FStringValue {
     /// # Panics
     ///
     /// Panics if `values` is less than 2. Use [`FStringValue::single`] instead.
-    pub fn concatenated(values: Vec<FStringPart>) -> Self {
+    pub fn concatenated(values: Vec<FStringPart>, range: TextRange) -> Self {
         assert!(values.len() > 1);
         Self {
-            inner: FStringValueInner::Concatenated(values),
+            range,
+            inner: ExprFStringInner::Concatenated(values),
         }
     }
 
     /// Returns `true` if the f-string is implicitly concatenated, `false` otherwise.
     pub fn is_implicit_concatenated(&self) -> bool {
-        matches!(self.inner, FStringValueInner::Concatenated(_))
+        matches!(self.inner, ExprFStringInner::Concatenated(_))
     }
 
     /// Returns a slice of all the [`FStringPart`]s contained in this value.
     pub fn as_slice(&self) -> &[FStringPart] {
         match &self.inner {
-            FStringValueInner::Single(part) => std::slice::from_ref(part),
-            FStringValueInner::Concatenated(parts) => parts,
+            ExprFStringInner::Single(part) => std::slice::from_ref(part),
+            ExprFStringInner::Concatenated(parts) => parts,
         }
     }
 
     /// Returns a mutable slice of all the [`FStringPart`]s contained in this value.
     fn as_mut_slice(&mut self) -> &mut [FStringPart] {
         match &mut self.inner {
-            FStringValueInner::Single(part) => std::slice::from_mut(part),
-            FStringValueInner::Concatenated(parts) => parts,
+            ExprFStringInner::Single(part) => std::slice::from_mut(part),
+            ExprFStringInner::Concatenated(parts) => parts,
         }
     }
 
@@ -1121,7 +1117,7 @@ impl FStringValue {
     }
 }
 
-impl<'a> IntoIterator for &'a FStringValue {
+impl<'a> IntoIterator for &'a ExprFString {
     type Item = &'a FStringPart;
     type IntoIter = Iter<'a, FStringPart>;
 
@@ -1130,9 +1126,10 @@ impl<'a> IntoIterator for &'a FStringValue {
     }
 }
 
-impl<'a> IntoIterator for &'a mut FStringValue {
+impl<'a> IntoIterator for &'a mut ExprFString {
     type Item = &'a mut FStringPart;
     type IntoIter = IterMut<'a, FStringPart>;
+
     fn into_iter(self) -> Self::IntoIter {
         self.iter_mut()
     }
@@ -1140,7 +1137,7 @@ impl<'a> IntoIterator for &'a mut FStringValue {
 
 /// An internal representation of [`FStringValue`].
 #[derive(Clone, Debug, PartialEq)]
-enum FStringValueInner {
+enum ExprFStringInner {
     /// A single f-string i.e., `f"foo"`.
     ///
     /// This is always going to be `FStringPart::FString` variant which is
@@ -1182,11 +1179,7 @@ impl Ranged for FString {
 
 impl From<FString> for Expr {
     fn from(payload: FString) -> Self {
-        ExprFString {
-            range: payload.range,
-            value: FStringValue::single(payload),
-        }
-        .into()
+        Expr::FString(ExprFString::single(payload))
     }
 }
 
@@ -1210,7 +1203,7 @@ impl Ranged for FStringElement {
 #[derive(Clone, Debug, Default, PartialEq)]
 pub struct ExprStringLiteral {
     pub range: TextRange,
-    pub value: StringLiteralValue,
+    inner: ExprStringLiteralInner,
 }
 
 impl From<ExprStringLiteral> for Expr {
@@ -1225,17 +1218,12 @@ impl Ranged for ExprStringLiteral {
     }
 }
 
-/// The value representing a [`ExprStringLiteral`].
-#[derive(Clone, Debug, Default, PartialEq)]
-pub struct StringLiteralValue {
-    inner: StringLiteralValueInner,
-}
-
-impl StringLiteralValue {
+impl ExprStringLiteral {
     /// Creates a new single string literal with the given value.
     pub fn single(string: StringLiteral) -> Self {
         Self {
-            inner: StringLiteralValueInner::Single(string),
+            range: string.range,
+            inner: ExprStringLiteralInner::Single(string),
         }
     }
 
@@ -1246,10 +1234,11 @@ impl StringLiteralValue {
     ///
     /// Panics if `strings` is less than 2. Use [`StringLiteralValue::single`]
     /// instead.
-    pub fn concatenated(strings: Vec<StringLiteral>) -> Self {
+    pub fn concatenated(strings: Vec<StringLiteral>, range: TextRange) -> Self {
         assert!(strings.len() > 1);
         Self {
-            inner: StringLiteralValueInner::Concatenated(ConcatenatedStringLiteral {
+            range,
+            inner: ExprStringLiteralInner::Concatenated(ConcatenatedStringLiteral {
                 strings,
                 value: OnceCell::new(),
             }),
@@ -1258,7 +1247,7 @@ impl StringLiteralValue {
 
     /// Returns `true` if the string literal is implicitly concatenated.
     pub const fn is_implicit_concatenated(&self) -> bool {
-        matches!(self.inner, StringLiteralValueInner::Concatenated(_))
+        matches!(self.inner, ExprStringLiteralInner::Concatenated(_))
     }
 
     /// Returns `true` if the string literal is a unicode string.
@@ -1272,16 +1261,16 @@ impl StringLiteralValue {
     /// Returns a slice of all the [`StringLiteral`] parts contained in this value.
     pub fn as_slice(&self) -> &[StringLiteral] {
         match &self.inner {
-            StringLiteralValueInner::Single(value) => std::slice::from_ref(value),
-            StringLiteralValueInner::Concatenated(value) => value.strings.as_slice(),
+            ExprStringLiteralInner::Single(value) => std::slice::from_ref(value),
+            ExprStringLiteralInner::Concatenated(value) => value.strings.as_slice(),
         }
     }
 
     /// Returns a mutable slice of all the [`StringLiteral`] parts contained in this value.
     fn as_mut_slice(&mut self) -> &mut [StringLiteral] {
         match &mut self.inner {
-            StringLiteralValueInner::Single(value) => std::slice::from_mut(value),
-            StringLiteralValueInner::Concatenated(value) => value.strings.as_mut_slice(),
+            ExprStringLiteralInner::Single(value) => std::slice::from_mut(value),
+            ExprStringLiteralInner::Concatenated(value) => value.strings.as_mut_slice(),
         }
     }
 
@@ -1318,13 +1307,13 @@ impl StringLiteralValue {
     /// string value is implicitly concatenated.
     pub fn to_str(&self) -> &str {
         match &self.inner {
-            StringLiteralValueInner::Single(value) => value.as_str(),
-            StringLiteralValueInner::Concatenated(value) => value.to_str(),
+            ExprStringLiteralInner::Single(value) => value.as_str(),
+            ExprStringLiteralInner::Concatenated(value) => value.to_str(),
         }
     }
 }
 
-impl<'a> IntoIterator for &'a StringLiteralValue {
+impl<'a> IntoIterator for &'a ExprStringLiteral {
     type Item = &'a StringLiteral;
     type IntoIter = Iter<'a, StringLiteral>;
 
@@ -1333,15 +1322,16 @@ impl<'a> IntoIterator for &'a StringLiteralValue {
     }
 }
 
-impl<'a> IntoIterator for &'a mut StringLiteralValue {
+impl<'a> IntoIterator for &'a mut ExprStringLiteral {
     type Item = &'a mut StringLiteral;
     type IntoIter = IterMut<'a, StringLiteral>;
+
     fn into_iter(self) -> Self::IntoIter {
         self.iter_mut()
     }
 }
 
-impl PartialEq<str> for StringLiteralValue {
+impl PartialEq<str> for ExprStringLiteral {
     fn eq(&self, other: &str) -> bool {
         if self.len() != other.len() {
             return false;
@@ -1351,13 +1341,13 @@ impl PartialEq<str> for StringLiteralValue {
     }
 }
 
-impl PartialEq<String> for StringLiteralValue {
+impl PartialEq<String> for ExprStringLiteral {
     fn eq(&self, other: &String) -> bool {
         self == other.as_str()
     }
 }
 
-impl fmt::Display for StringLiteralValue {
+impl fmt::Display for ExprStringLiteral {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.write_str(self.to_str())
     }
@@ -1365,7 +1355,7 @@ impl fmt::Display for StringLiteralValue {
 
 /// An internal representation of [`StringLiteralValue`].
 #[derive(Clone, Debug, PartialEq)]
-enum StringLiteralValueInner {
+enum ExprStringLiteralInner {
     /// A single string literal i.e., `"foo"`.
     Single(StringLiteral),
 
@@ -1373,7 +1363,7 @@ enum StringLiteralValueInner {
     Concatenated(ConcatenatedStringLiteral),
 }
 
-impl Default for StringLiteralValueInner {
+impl Default for ExprStringLiteralInner {
     fn default() -> Self {
         Self::Single(StringLiteral::default())
     }
@@ -1411,11 +1401,7 @@ impl StringLiteral {
 
 impl From<StringLiteral> for Expr {
     fn from(payload: StringLiteral) -> Self {
-        ExprStringLiteral {
-            range: payload.range,
-            value: StringLiteralValue::single(payload),
-        }
-        .into()
+        Expr::StringLiteral(ExprStringLiteral::single(payload))
     }
 }
 
@@ -1466,7 +1452,7 @@ impl Debug for ConcatenatedStringLiteral {
 #[derive(Clone, Debug, Default, PartialEq)]
 pub struct ExprBytesLiteral {
     pub range: TextRange,
-    pub value: BytesLiteralValue,
+    inner: ExprBytesLiteralInner,
 }
 
 impl From<ExprBytesLiteral> for Expr {
@@ -1481,17 +1467,12 @@ impl Ranged for ExprBytesLiteral {
     }
 }
 
-/// The value representing a [`ExprBytesLiteral`].
-#[derive(Clone, Debug, Default, PartialEq)]
-pub struct BytesLiteralValue {
-    inner: BytesLiteralValueInner,
-}
-
-impl BytesLiteralValue {
+impl ExprBytesLiteral {
     /// Creates a new single bytes literal with the given value.
     pub fn single(value: BytesLiteral) -> Self {
         Self {
-            inner: BytesLiteralValueInner::Single(value),
+            range: value.range,
+            inner: ExprBytesLiteralInner::Single(value),
         }
     }
 
@@ -1502,31 +1483,32 @@ impl BytesLiteralValue {
     ///
     /// Panics if `values` is less than 2. Use [`BytesLiteralValue::single`]
     /// instead.
-    pub fn concatenated(values: Vec<BytesLiteral>) -> Self {
+    pub fn concatenated(values: Vec<BytesLiteral>, range: TextRange) -> Self {
         assert!(values.len() > 1);
         Self {
-            inner: BytesLiteralValueInner::Concatenated(values),
+            range,
+            inner: ExprBytesLiteralInner::Concatenated(values),
         }
     }
 
     /// Returns `true` if the bytes literal is implicitly concatenated.
     pub const fn is_implicit_concatenated(&self) -> bool {
-        matches!(self.inner, BytesLiteralValueInner::Concatenated(_))
+        matches!(self.inner, ExprBytesLiteralInner::Concatenated(_))
     }
 
     /// Returns a slice of all the [`BytesLiteral`] parts contained in this value.
     pub fn as_slice(&self) -> &[BytesLiteral] {
         match &self.inner {
-            BytesLiteralValueInner::Single(value) => std::slice::from_ref(value),
-            BytesLiteralValueInner::Concatenated(value) => value.as_slice(),
+            ExprBytesLiteralInner::Single(value) => std::slice::from_ref(value),
+            ExprBytesLiteralInner::Concatenated(value) => value.as_slice(),
         }
     }
 
     /// Returns a mutable slice of all the [`BytesLiteral`] parts contained in this value.
     fn as_mut_slice(&mut self) -> &mut [BytesLiteral] {
         match &mut self.inner {
-            BytesLiteralValueInner::Single(value) => std::slice::from_mut(value),
-            BytesLiteralValueInner::Concatenated(value) => value.as_mut_slice(),
+            ExprBytesLiteralInner::Single(value) => std::slice::from_mut(value),
+            ExprBytesLiteralInner::Concatenated(value) => value.as_mut_slice(),
         }
     }
 
@@ -1557,7 +1539,7 @@ impl BytesLiteralValue {
     }
 }
 
-impl<'a> IntoIterator for &'a BytesLiteralValue {
+impl<'a> IntoIterator for &'a ExprBytesLiteral {
     type Item = &'a BytesLiteral;
     type IntoIter = Iter<'a, BytesLiteral>;
 
@@ -1566,15 +1548,16 @@ impl<'a> IntoIterator for &'a BytesLiteralValue {
     }
 }
 
-impl<'a> IntoIterator for &'a mut BytesLiteralValue {
+impl<'a> IntoIterator for &'a mut ExprBytesLiteral {
     type Item = &'a mut BytesLiteral;
     type IntoIter = IterMut<'a, BytesLiteral>;
+
     fn into_iter(self) -> Self::IntoIter {
         self.iter_mut()
     }
 }
 
-impl PartialEq<[u8]> for BytesLiteralValue {
+impl PartialEq<[u8]> for ExprBytesLiteral {
     fn eq(&self, other: &[u8]) -> bool {
         if self.len() != other.len() {
             return false;
@@ -1588,7 +1571,7 @@ impl PartialEq<[u8]> for BytesLiteralValue {
 
 /// An internal representation of [`BytesLiteralValue`].
 #[derive(Clone, Debug, PartialEq)]
-enum BytesLiteralValueInner {
+enum ExprBytesLiteralInner {
     /// A single bytes literal i.e., `b"foo"`.
     Single(BytesLiteral),
 
@@ -1596,7 +1579,7 @@ enum BytesLiteralValueInner {
     Concatenated(Vec<BytesLiteral>),
 }
 
-impl Default for BytesLiteralValueInner {
+impl Default for ExprBytesLiteralInner {
     fn default() -> Self {
         Self::Single(BytesLiteral::default())
     }
@@ -1607,7 +1590,7 @@ impl Default for BytesLiteralValueInner {
 #[derive(Clone, Debug, Default, PartialEq)]
 pub struct BytesLiteral {
     pub range: TextRange,
-    pub value: Vec<u8>,
+    pub value: Box<[u8]>,
 }
 
 impl Ranged for BytesLiteral {
@@ -1620,7 +1603,7 @@ impl Deref for BytesLiteral {
     type Target = [u8];
 
     fn deref(&self) -> &Self::Target {
-        self.value.as_slice()
+        &self.value
     }
 }
 
@@ -1633,11 +1616,7 @@ impl BytesLiteral {
 
 impl From<BytesLiteral> for Expr {
     fn from(payload: BytesLiteral) -> Self {
-        ExprBytesLiteral {
-            range: payload.range,
-            value: BytesLiteralValue::single(payload),
-        }
-        .into()
+        Expr::BytesLiteral(ExprBytesLiteral::single(payload))
     }
 }
 

crates/ruff_python_codegen/Cargo.toml

@@ -11,6 +11,7 @@ repository = { workspace = true }
 license = { workspace = true }
 
 [lib]
+doctest = false
 
 [dependencies]
 ruff_python_ast = { path = "../ruff_python_ast" }

crates/ruff_python_codegen/src/generator.rs

@@ -1705,6 +1705,7 @@ class Foo:
         assert_round_trip!(r#"f"{ chr(65)  =   !s}""#);
         assert_round_trip!(r#"f"{ chr(65)  =   !r}""#);
         assert_round_trip!(r#"f"{ chr(65)  =   :#x}""#);
+        assert_round_trip!(r#"f"{  ( chr(65)  ) = }""#);
         assert_round_trip!(r#"f"{a=!r:0.05f}""#);
     }
 

crates/ruff_python_formatter/Cargo.toml

@@ -10,6 +10,9 @@ documentation = { workspace = true }
 repository = { workspace = true }
 license = { workspace = true }
 
+[lib]
+doctest= false
+
 [dependencies]
 ruff_cache = { path = "../ruff_cache" }
 ruff_formatter = { path = "../ruff_formatter" }

crates/ruff_python_formatter/resources/test/fixtures/ruff/.editorconfig

@@ -4,4 +4,8 @@ ij_formatter_enabled = false
 
 ["range_formatting/*.py"]
 generated_code = true
+ij_formatter_enabled = false
+
+[docstring_tab_indentation.py]
+generated_code = true
 ij_formatter_enabled = false

crates/ruff_python_formatter/resources/test/fixtures/ruff/docstring_tab_indentation.options.json

@@ -0,0 +1,10 @@
+[
+  {
+    "indent_style": "tab",
+    "indent_width": 4
+  },
+  {
+    "indent_style": "tab",
+    "indent_width": 8
+  }
+]

crates/ruff_python_formatter/resources/test/fixtures/ruff/docstring_tab_indentation.py

@@ -0,0 +1,72 @@
+# Tests the behavior of the formatter when it comes to tabs inside docstrings
+# when using `indent_style="tab`
+
+# The example below uses tabs exclusively. The formatter should preserve the tab indentation
+# of `arg1`.
+def tab_argument(arg1: str) -> None:
+	"""
+	Arguments:
+		arg1: super duper arg with 2 tabs in front
+	"""
+
+# The `arg1` is intended with spaces. The formatter should not change the spaces to a tab
+# because it must assume that the spaces are used for alignment and not indentation.
+def space_argument(arg1: str) -> None:
+	"""
+	Arguments:
+	        arg1: super duper arg with a tab and a space in front
+	"""
+
+def under_indented(arg1: str) -> None:
+	"""
+	Arguments:
+	        arg1: super duper arg with a tab and a space in front
+arg2: Not properly indented
+	"""
+
+def under_indented_tabs(arg1: str) -> None:
+	"""
+	Arguments:
+		arg1: super duper arg with a tab and a space in front
+arg2: Not properly indented
+	"""
+
+def spaces_tabs_over_indent(arg1: str) -> None:
+    """
+    Arguments:
+      	arg1: super duper arg with a tab and a space in front
+    """
+
+# The docstring itself is indented with spaces but the argument is indented by a tab.
+# Keep the tab indentation of the argument, convert th docstring indent to tabs.
+def space_indented_docstring_containing_tabs(arg1: str) -> None:
+    """
+    Arguments:
+    	arg1: super duper arg
+    """
+
+
+# The docstring uses tabs, spaces, tabs indentation.
+# Fallback to use space indentation
+def mixed_indentation(arg1: str) -> None:
+	"""
+	Arguments:
+	        	arg1: super duper arg with a tab and a space in front
+	"""
+
+
+# The example shows an ascii art. The formatter should not change the spaces
+# to tabs because it breaks the ASCII art when inspecting the docstring with `inspect.cleandoc(ascii_art.__doc__)`
+# when using an indent width other than 8.
+def ascii_art():
+	r"""
+	Look at this beautiful tree.
+
+	    a
+	   / \
+	  b   c
+	 / \
+	d   e
+	"""
+
+

crates/ruff_python_formatter/resources/test/fixtures/ruff/expression/fstring.options.json

@@ -0,0 +1,8 @@
+[
+  {
+    "preview": "enabled"
+  },
+  {
+    "preview": "disabled"
+  }
+]