[ty] Use CompactStr for StringLiteralType values

CHANGELOG.md

@@ -1,36 +1,5 @@
 # Changelog
 
-## 0.12.4
-
-### Preview features
-
-- \[`flake8-type-checking`, `pyupgrade`, `ruff`\] Add `from __future__ import annotations` when it would allow new fixes (`TC001`, `TC002`, `TC003`, `UP037`, `RUF013`) ([#19100](https://github.com/astral-sh/ruff/pull/19100))
-- \[`flake8-use-pathlib`\] Add autofix for `PTH109` ([#19245](https://github.com/astral-sh/ruff/pull/19245))
-- \[`pylint`\] Detect indirect `pathlib.Path` usages for `unspecified-encoding` (`PLW1514`) ([#19304](https://github.com/astral-sh/ruff/pull/19304))
-
-### Bug fixes
-
-- \[`flake8-bugbear`\] Fix `B017` false negatives for keyword exception arguments ([#19217](https://github.com/astral-sh/ruff/pull/19217))
-- \[`flake8-use-pathlib`\] Fix false negative on direct `Path()` instantiation (`PTH210`) ([#19388](https://github.com/astral-sh/ruff/pull/19388))
-- \[`flake8-django`\] Fix `DJ008` false positive for abstract models with type-annotated `abstract` field ([#19221](https://github.com/astral-sh/ruff/pull/19221))
-- \[`isort`\] Fix `I002` import insertion after docstring with multiple string statements ([#19222](https://github.com/astral-sh/ruff/pull/19222))
-- \[`isort`\] Treat form feed as valid whitespace before a semicolon ([#19343](https://github.com/astral-sh/ruff/pull/19343))
-- \[`pydoclint`\] Fix `SyntaxError` from fixes with line continuations (`D201`, `D202`) ([#19246](https://github.com/astral-sh/ruff/pull/19246))
-- \[`refurb`\] `FURB164` fix should validate arguments and should usually be marked unsafe ([#19136](https://github.com/astral-sh/ruff/pull/19136))
-
-### Rule changes
-
-- \[`flake8-use-pathlib`\] Skip single dots for `invalid-pathlib-with-suffix` (`PTH210`) on versions >= 3.14 ([#19331](https://github.com/astral-sh/ruff/pull/19331))
-- \[`pep8_naming`\] Avoid false positives on standard library functions with uppercase names (`N802`) ([#18907](https://github.com/astral-sh/ruff/pull/18907))
-- \[`pycodestyle`\] Handle brace escapes for t-strings in logical lines ([#19358](https://github.com/astral-sh/ruff/pull/19358))
-- \[`pylint`\] Extend invalid string character rules to include t-strings ([#19355](https://github.com/astral-sh/ruff/pull/19355))
-- \[`ruff`\] Allow `strict` kwarg when checking for `starmap-zip` (`RUF058`) in Python 3.14+ ([#19333](https://github.com/astral-sh/ruff/pull/19333))
-
-### Documentation
-
-- \[`flake8-type-checking`\] Make `TC010` docs example more realistic ([#19356](https://github.com/astral-sh/ruff/pull/19356))
-- Make more documentation examples error out-of-the-box ([#19288](https://github.com/astral-sh/ruff/pull/19288),[#19272](https://github.com/astral-sh/ruff/pull/19272),[#19291](https://github.com/astral-sh/ruff/pull/19291),[#19296](https://github.com/astral-sh/ruff/pull/19296),[#19292](https://github.com/astral-sh/ruff/pull/19292),[#19295](https://github.com/astral-sh/ruff/pull/19295),[#19297](https://github.com/astral-sh/ruff/pull/19297),[#19309](https://github.com/astral-sh/ruff/pull/19309))
-
 ## 0.12.3
 
 ### Preview features

Cargo.lock

@@ -2711,7 +2711,7 @@ dependencies = [
 
 [[package]]
 name = "ruff"
-version = "0.12.4"
+version = "0.12.3"
 dependencies = [
  "anyhow",
  "argfile",
@@ -2962,7 +2962,7 @@ dependencies = [
 
 [[package]]
 name = "ruff_linter"
-version = "0.12.4"
+version = "0.12.3"
 dependencies = [
  "aho-corasick",
  "anyhow",
@@ -3295,7 +3295,7 @@ dependencies = [
 
 [[package]]
 name = "ruff_wasm"
-version = "0.12.4"
+version = "0.12.3"
 dependencies = [
  "console_error_panic_hook",
  "console_log",
@@ -4287,7 +4287,6 @@ dependencies = [
  "strum_macros",
  "tempfile",
  "test-case",
- "thin-vec",
  "thiserror 2.0.12",
  "tracing",
  "ty_python_semantic",
@@ -4301,7 +4300,6 @@ name = "ty_server"
 version = "0.0.0"
 dependencies = [
  "anyhow",
- "bitflags 2.9.1",
  "crossbeam",
  "jod-thread",
  "libc",

Cargo.toml

@@ -163,7 +163,6 @@ strum_macros = { version = "0.27.0" }
 syn = { version = "2.0.55" }
 tempfile = { version = "3.9.0" }
 test-case = { version = "3.3.1" }
-thin-vec = { version = "0.2.14" }
 thiserror = { version = "2.0.0" }
 tikv-jemallocator = { version = "0.6.0" }
 toml = { version = "0.9.0" }

README.md

@@ -148,8 +148,8 @@ curl -LsSf https://astral.sh/ruff/install.sh | sh
 powershell -c "irm https://astral.sh/ruff/install.ps1 | iex"
 
 # For a specific version.
-curl -LsSf https://astral.sh/ruff/0.12.4/install.sh | sh
-powershell -c "irm https://astral.sh/ruff/0.12.4/install.ps1 | iex"
+curl -LsSf https://astral.sh/ruff/0.12.3/install.sh | sh
+powershell -c "irm https://astral.sh/ruff/0.12.3/install.ps1 | iex"
 ```
 
 You can also install Ruff via [Homebrew](https://formulae.brew.sh/formula/ruff), [Conda](https://anaconda.org/conda-forge/ruff),
@@ -182,7 +182,7 @@ 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: v0.12.4
+  rev: v0.12.3
   hooks:
     # Run the linter.
     - id: ruff-check

crates/ruff/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ruff"
-version = "0.12.4"
+version = "0.12.3"
 publish = true
 authors = { workspace = true }
 edition = { workspace = true }

crates/ruff/tests/lint.rs

@@ -5718,11 +5718,8 @@ match 42:  # invalid-syntax
 
     let snapshot = format!("output_format_{output_format}");
 
-    let project_dir = dunce::canonicalize(tempdir.path())?;
-
     insta::with_settings!({
         filters => vec![
-            (tempdir_filter(&project_dir).as_str(), "[TMP]/"),
             (tempdir_filter(&tempdir).as_str(), "[TMP]/"),
             (r#""[^"]+\\?/?input.py"#, r#""[TMP]/input.py"#),
             (ruff_linter::VERSION, "[VERSION]"),

crates/ruff_linter/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ruff_linter"
-version = "0.12.4"
+version = "0.12.3"
 publish = false
 authors = { workspace = true }
 edition = { workspace = true }

crates/ruff_linter/resources/test/fixtures/flake8_use_pathlib/full_name.py

@@ -104,6 +104,3 @@ os.chmod(x)
 os.replace("src", "dst", src_dir_fd=1, dst_dir_fd=2)
 os.replace("src", "dst", src_dir_fd=1)
 os.replace("src", "dst", dst_dir_fd=2)
-
-os.getcwd()
-os.getcwdb()

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

@@ -1044,6 +1044,7 @@ pub(crate) fn expression(expr: &Expr, checker: &Checker) {
                 Rule::OsMakedirs,
                 Rule::OsRename,
                 Rule::OsReplace,
+                Rule::OsGetcwd,
                 Rule::OsStat,
                 Rule::OsPathJoin,
                 Rule::OsPathSamefile,
@@ -1109,9 +1110,6 @@ pub(crate) fn expression(expr: &Expr, checker: &Checker) {
                 if checker.is_rule_enabled(Rule::OsReadlink) {
                     flake8_use_pathlib::rules::os_readlink(checker, call, segments);
                 }
-                if checker.is_rule_enabled(Rule::OsGetcwd) {
-                    flake8_use_pathlib::rules::os_getcwd(checker, call, segments);
-                }
                 if checker.is_rule_enabled(Rule::PathConstructorCurrentDirectory) {
                     flake8_use_pathlib::rules::path_constructor_current_directory(
                         checker, call, segments,

crates/ruff_linter/src/codes.rs

@@ -928,7 +928,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         (Flake8UsePathlib, "106") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsRmdir),
         (Flake8UsePathlib, "107") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsRemove),
         (Flake8UsePathlib, "108") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsUnlink),
-        (Flake8UsePathlib, "109") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsGetcwd),
+        (Flake8UsePathlib, "109") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsGetcwd),
         (Flake8UsePathlib, "110") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsPathExists),
         (Flake8UsePathlib, "111") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsPathExpanduser),
         (Flake8UsePathlib, "112") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsPathIsdir),

crates/ruff_linter/src/preview.rs

@@ -134,11 +134,6 @@ pub(crate) const fn is_fix_os_path_dirname_enabled(settings: &LinterSettings) ->
     settings.preview.is_enabled()
 }
 
-// https://github.com/astral-sh/ruff/pull/19245
-pub(crate) const fn is_fix_os_getcwd_enabled(settings: &LinterSettings) -> bool {
-    settings.preview.is_enabled()
-}
-
 // https://github.com/astral-sh/ruff/pull/11436
 // https://github.com/astral-sh/ruff/pull/11168
 pub(crate) const fn is_dunder_init_fix_unused_import_enabled(settings: &LinterSettings) -> bool {

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

@@ -1,6 +1,5 @@
 pub(crate) use glob_rule::*;
 pub(crate) use invalid_pathlib_with_suffix::*;
-pub(crate) use os_getcwd::*;
 pub(crate) use os_path_abspath::*;
 pub(crate) use os_path_basename::*;
 pub(crate) use os_path_dirname::*;
@@ -24,7 +23,6 @@ pub(crate) use replaceable_by_pathlib::*;
 
 mod glob_rule;
 mod invalid_pathlib_with_suffix;
-mod os_getcwd;
 mod os_path_abspath;
 mod os_path_basename;
 mod os_path_dirname;

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

@@ -1,100 +0,0 @@
-use crate::checkers::ast::Checker;
-use crate::importer::ImportRequest;
-use crate::preview::is_fix_os_getcwd_enabled;
-use crate::{FixAvailability, Violation};
-use ruff_diagnostics::{Applicability, Edit, Fix};
-use ruff_macros::{ViolationMetadata, derive_message_formats};
-use ruff_python_ast::ExprCall;
-use ruff_text_size::Ranged;
-
-/// ## What it does
-/// Checks for uses of `os.getcwd` and `os.getcwdb`.
-///
-/// ## Why is this bad?
-/// `pathlib` offers a high-level API for path manipulation, as compared to
-/// the lower-level API offered by `os`. When possible, using `Path` object
-/// methods such as `Path.cwd()` can improve readability over the `os`
-/// module's counterparts (e.g., `os.getcwd()`).
-///
-/// ## Examples
-/// ```python
-/// import os
-///
-/// cwd = os.getcwd()
-/// ```
-///
-/// Use instead:
-/// ```python
-/// from pathlib import Path
-///
-/// cwd = Path.cwd()
-/// ```
-///
-/// ## Known issues
-/// While using `pathlib` can improve the readability and type safety of your code,
-/// it can be less performant than the lower-level alternatives that work directly with strings,
-/// especially on older versions of Python.
-///
-/// ## Fix Safety
-/// This rule's fix is marked as unsafe if the replacement would remove comments attached to the original expression.
-///
-/// ## References
-/// - [Python documentation: `Path.cwd`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.cwd)
-/// - [Python documentation: `os.getcwd`](https://docs.python.org/3/library/os.html#os.getcwd)
-/// - [Python documentation: `os.getcwdb`](https://docs.python.org/3/library/os.html#os.getcwdb)
-/// - [PEP 428 – The pathlib module – object-oriented filesystem paths](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/)
-/// - [No really, pathlib is great](https://treyhunner.com/2019/01/no-really-pathlib-is-great/)
-#[derive(ViolationMetadata)]
-pub(crate) struct OsGetcwd;
-
-impl Violation for OsGetcwd {
-    const FIX_AVAILABILITY: FixAvailability = FixAvailability::Sometimes;
-    #[derive_message_formats]
-    fn message(&self) -> String {
-        "`os.getcwd()` should be replaced by `Path.cwd()`".to_string()
-    }
-
-    fn fix_title(&self) -> Option<String> {
-        Some("Replace with `Path.cwd()`".to_string())
-    }
-}
-
-/// PTH109
-pub(crate) fn os_getcwd(checker: &Checker, call: &ExprCall, segments: &[&str]) {
-    if !matches!(segments, ["os", "getcwd" | "getcwdb"]) {
-        return;
-    }
-
-    let range = call.range();
-    let mut diagnostic = checker.report_diagnostic(OsGetcwd, call.func.range());
-
-    if !call.arguments.is_empty() {
-        return;
-    }
-
-    if is_fix_os_getcwd_enabled(checker.settings()) {
-        diagnostic.try_set_fix(|| {
-            let (import_edit, binding) = checker.importer().get_or_import_symbol(
-                &ImportRequest::import("pathlib", "Path"),
-                call.start(),
-                checker.semantic(),
-            )?;
-
-            let applicability = if checker.comment_ranges().intersects(range) {
-                Applicability::Unsafe
-            } else {
-                Applicability::Safe
-            };
-
-            let replacement = format!("{binding}.cwd()");
-
-            Ok(Fix::applicable_edits(
-                Edit::range_replacement(replacement, range),
-                [import_edit],
-                applicability,
-            ))
-        });
-    }
-}

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

@@ -7,8 +7,8 @@ use crate::checkers::ast::Checker;
 use crate::rules::flake8_use_pathlib::helpers::is_keyword_only_argument_non_default;
 use crate::rules::flake8_use_pathlib::rules::Glob;
 use crate::rules::flake8_use_pathlib::violations::{
-    BuiltinOpen, Joiner, OsChmod, OsListdir, OsMakedirs, OsMkdir, OsPathJoin, OsPathSamefile,
-    OsPathSplitext, OsRename, OsReplace, OsStat, OsSymlink, PyPath,
+    BuiltinOpen, Joiner, OsChmod, OsGetcwd, OsListdir, OsMakedirs, OsMkdir, OsPathJoin,
+    OsPathSamefile, OsPathSplitext, OsRename, OsReplace, OsStat, OsSymlink, PyPath,
 };
 
 pub(crate) fn replaceable_by_pathlib(checker: &Checker, call: &ExprCall) {
@@ -83,6 +83,10 @@ pub(crate) fn replaceable_by_pathlib(checker: &Checker, call: &ExprCall) {
             }
             checker.report_diagnostic_if_enabled(OsReplace, range)
         }
+        // PTH109
+        ["os", "getcwd"] => checker.report_diagnostic_if_enabled(OsGetcwd, range),
+        ["os", "getcwdb"] => checker.report_diagnostic_if_enabled(OsGetcwd, range),
+
         // PTH116
         ["os", "stat"] => {
             // `dir_fd` is not supported by pathlib, so check if it's set to non-default values.

crates/ruff_linter/src/rules/flake8_use_pathlib/snapshots/ruff_linter__rules__flake8_use_pathlib__tests__full_name.py.snap

@@ -103,7 +103,6 @@ full_name.py:16:1: PTH109 `os.getcwd()` should be replaced by `Path.cwd()`
 17 | b = os.path.exists(p)
 18 | bb = os.path.expanduser(p)
    |
-   = help: Replace with `Path.cwd()`
 
 full_name.py:17:5: PTH110 `os.path.exists()` should be replaced by `Path.exists()`
    |
@@ -293,7 +292,6 @@ full_name.py:35:1: PTH109 `os.getcwd()` should be replaced by `Path.cwd()`
 36 | os.path.join(p, *q)
 37 | os.sep.join(p, *q)
    |
-   = help: Replace with `Path.cwd()`
 
 full_name.py:36:1: PTH118 `os.path.join()` should be replaced by `Path.joinpath()`
    |
@@ -362,21 +360,3 @@ full_name.py:71:1: PTH123 `open()` should be replaced by `Path.open()`
 72 |
 73 | # https://github.com/astral-sh/ruff/issues/17693
    |
-
-full_name.py:108:1: PTH109 `os.getcwd()` should be replaced by `Path.cwd()`
-    |
-106 | os.replace("src", "dst", dst_dir_fd=2)
-107 |
-108 | os.getcwd()
-    | ^^^^^^^^^ PTH109
-109 | os.getcwdb()
-    |
-    = help: Replace with `Path.cwd()`
-
-full_name.py:109:1: PTH109 `os.getcwd()` should be replaced by `Path.cwd()`
-    |
-108 | os.getcwd()
-109 | os.getcwdb()
-    | ^^^^^^^^^^ PTH109
-    |
-    = help: Replace with `Path.cwd()`

crates/ruff_linter/src/rules/flake8_use_pathlib/snapshots/ruff_linter__rules__flake8_use_pathlib__tests__import_as.py.snap

@@ -103,7 +103,6 @@ import_as.py:16:1: PTH109 `os.getcwd()` should be replaced by `Path.cwd()`
 17 | b = foo_p.exists(p)
 18 | bb = foo_p.expanduser(p)
    |
-   = help: Replace with `Path.cwd()`
 
 import_as.py:17:5: PTH110 `os.path.exists()` should be replaced by `Path.exists()`
    |

crates/ruff_linter/src/rules/flake8_use_pathlib/snapshots/ruff_linter__rules__flake8_use_pathlib__tests__import_from.py.snap

@@ -103,7 +103,6 @@ import_from.py:18:1: PTH109 `os.getcwd()` should be replaced by `Path.cwd()`
 19 | b = exists(p)
 20 | bb = expanduser(p)
    |
-   = help: Replace with `Path.cwd()`
 
 import_from.py:19:5: PTH110 `os.path.exists()` should be replaced by `Path.exists()`
    |

crates/ruff_linter/src/rules/flake8_use_pathlib/snapshots/ruff_linter__rules__flake8_use_pathlib__tests__import_from_as.py.snap

@@ -103,7 +103,6 @@ import_from_as.py:23:1: PTH109 `os.getcwd()` should be replaced by `Path.cwd()`
 24 | b = xexists(p)
 25 | bb = xexpanduser(p)
    |
-   = help: Replace with `Path.cwd()`
 
 import_from_as.py:24:5: PTH110 `os.path.exists()` should be replaced by `Path.exists()`
    |

crates/ruff_linter/src/rules/flake8_use_pathlib/snapshots/ruff_linter__rules__flake8_use_pathlib__tests__preview_full_name.py.snap

@@ -168,7 +168,6 @@ full_name.py:16:1: PTH109 `os.getcwd()` should be replaced by `Path.cwd()`
 17 | b = os.path.exists(p)
 18 | bb = os.path.expanduser(p)
    |
-   = help: Replace with `Path.cwd()`
 
 full_name.py:17:5: PTH110 [*] `os.path.exists()` should be replaced by `Path.exists()`
    |
@@ -511,7 +510,6 @@ full_name.py:35:1: PTH109 `os.getcwd()` should be replaced by `Path.cwd()`
 36 | os.path.join(p, *q)
 37 | os.sep.join(p, *q)
    |
-   = help: Replace with `Path.cwd()`
 
 full_name.py:36:1: PTH118 `os.path.join()` should be replaced by `Path.joinpath()`
    |
@@ -580,50 +578,3 @@ full_name.py:71:1: PTH123 `open()` should be replaced by `Path.open()`
 72 |
 73 | # https://github.com/astral-sh/ruff/issues/17693
    |
-
-full_name.py:108:1: PTH109 [*] `os.getcwd()` should be replaced by `Path.cwd()`
-    |
-106 | os.replace("src", "dst", dst_dir_fd=2)
-107 |
-108 | os.getcwd()
-    | ^^^^^^^^^ PTH109
-109 | os.getcwdb()
-    |
-    = help: Replace with `Path.cwd()`
-
-ℹ Safe fix
-1   1   | import os
-2   2   | import os.path
-    3   |+import pathlib
-3   4   | 
-4   5   | p = "/foo"
-5   6   | q = "bar"
---------------------------------------------------------------------------------
-105 106 | os.replace("src", "dst", src_dir_fd=1)
-106 107 | os.replace("src", "dst", dst_dir_fd=2)
-107 108 | 
-108     |-os.getcwd()
-    109 |+pathlib.Path.cwd()
-109 110 | os.getcwdb()
-
-full_name.py:109:1: PTH109 [*] `os.getcwd()` should be replaced by `Path.cwd()`
-    |
-108 | os.getcwd()
-109 | os.getcwdb()
-    | ^^^^^^^^^^ PTH109
-    |
-    = help: Replace with `Path.cwd()`
-
-ℹ Safe fix
-1   1   | import os
-2   2   | import os.path
-    3   |+import pathlib
-3   4   | 
-4   5   | p = "/foo"
-5   6   | q = "bar"
---------------------------------------------------------------------------------
-106 107 | os.replace("src", "dst", dst_dir_fd=2)
-107 108 | 
-108 109 | os.getcwd()
-109     |-os.getcwdb()
-    110 |+pathlib.Path.cwd()

crates/ruff_linter/src/rules/flake8_use_pathlib/snapshots/ruff_linter__rules__flake8_use_pathlib__tests__preview_import_as.py.snap

@@ -168,7 +168,6 @@ import_as.py:16:1: PTH109 `os.getcwd()` should be replaced by `Path.cwd()`
 17 | b = foo_p.exists(p)
 18 | bb = foo_p.expanduser(p)
    |
-   = help: Replace with `Path.cwd()`
 
 import_as.py:17:5: PTH110 [*] `os.path.exists()` should be replaced by `Path.exists()`
    |

crates/ruff_linter/src/rules/flake8_use_pathlib/snapshots/ruff_linter__rules__flake8_use_pathlib__tests__preview_import_from.py.snap

@@ -172,7 +172,6 @@ import_from.py:18:1: PTH109 `os.getcwd()` should be replaced by `Path.cwd()`
 19 | b = exists(p)
 20 | bb = expanduser(p)
    |
-   = help: Replace with `Path.cwd()`
 
 import_from.py:19:5: PTH110 [*] `os.path.exists()` should be replaced by `Path.exists()`
    |

crates/ruff_linter/src/rules/flake8_use_pathlib/snapshots/ruff_linter__rules__flake8_use_pathlib__tests__preview_import_from_as.py.snap

@@ -172,7 +172,6 @@ import_from_as.py:23:1: PTH109 `os.getcwd()` should be replaced by `Path.cwd()`
 24 | b = xexists(p)
 25 | bb = xexpanduser(p)
    |
-   = help: Replace with `Path.cwd()`
 
 import_from_as.py:24:5: PTH110 [*] `os.path.exists()` should be replaced by `Path.exists()`
    |

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

@@ -230,6 +230,52 @@ impl Violation for OsReplace {
     }
 }
 
+/// ## What it does
+/// Checks for uses of `os.getcwd` and `os.getcwdb`.
+///
+/// ## Why is this bad?
+/// `pathlib` offers a high-level API for path manipulation, as compared to
+/// the lower-level API offered by `os`. When possible, using `Path` object
+/// methods such as `Path.cwd()` can improve readability over the `os`
+/// module's counterparts (e.g., `os.getcwd()`).
+///
+/// ## Examples
+/// ```python
+/// import os
+///
+/// cwd = os.getcwd()
+/// ```
+///
+/// Use instead:
+/// ```python
+/// from pathlib import Path
+///
+/// cwd = Path.cwd()
+/// ```
+///
+/// ## Known issues
+/// While using `pathlib` can improve the readability and type safety of your code,
+/// it can be less performant than the lower-level alternatives that work directly with strings,
+/// especially on older versions of Python.
+///
+/// ## References
+/// - [Python documentation: `Path.cwd`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.cwd)
+/// - [Python documentation: `os.getcwd`](https://docs.python.org/3/library/os.html#os.getcwd)
+/// - [Python documentation: `os.getcwdb`](https://docs.python.org/3/library/os.html#os.getcwdb)
+/// - [PEP 428 – The pathlib module – object-oriented filesystem paths](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/)
+/// - [No really, pathlib is great](https://treyhunner.com/2019/01/no-really-pathlib-is-great/)
+#[derive(ViolationMetadata)]
+pub(crate) struct OsGetcwd;
+
+impl Violation for OsGetcwd {
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        "`os.getcwd()` should be replaced by `Path.cwd()`".to_string()
+    }
+}
+
 /// ## What it does
 /// Checks for uses of `os.stat`.
 ///

crates/ruff_wasm/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ruff_wasm"
-version = "0.12.4"
+version = "0.12.3"
 publish = false
 authors = { workspace = true }
 edition = { workspace = true }

crates/ty_project/src/lib.rs

@@ -469,14 +469,6 @@ impl Project {
             self.set_file_set(db).to(IndexedFiles::lazy());
         }
     }
-
-    /// Check if the project's settings have any issues
-    pub fn check_settings(&self, db: &dyn Db) -> Vec<Diagnostic> {
-        self.settings_diagnostics(db)
-            .iter()
-            .map(OptionDiagnostic::to_diagnostic)
-            .collect()
-    }
 }
 
 #[salsa::tracked(returns(deref), heap_size=get_size2::GetSize::get_heap_size)]

crates/ty_python_semantic/Cargo.toml

@@ -35,7 +35,6 @@ indexmap = { workspace = true }
 itertools = { workspace = true }
 ordermap = { workspace = true }
 salsa = { workspace = true, features = ["compact_str"] }
-thin-vec = { workspace = true }
 thiserror = { workspace = true }
 tracing = { workspace = true }
 rustc-hash = { workspace = true }

crates/ty_python_semantic/src/semantic_index.rs

@@ -26,7 +26,6 @@ use crate::semantic_index::place::{
 };
 use crate::semantic_index::use_def::{EagerSnapshotKey, ScopedEagerSnapshotId, UseDefMap};
 use crate::semantic_model::HasTrackedScope;
-use crate::util::get_size::ThinVecSized;
 use crate::util::get_size::untracked_arc_size;
 
 pub mod ast_ids;
@@ -239,7 +238,7 @@ pub(crate) struct SemanticIndex<'db> {
     eager_snapshots: FxHashMap<EagerSnapshotKey, ScopedEagerSnapshotId>,
 
     /// List of all semantic syntax errors in this file.
-    semantic_syntax_errors: ThinVecSized<SemanticSyntaxError>,
+    semantic_syntax_errors: Vec<SemanticSyntaxError>,
 
     /// Set of all generator functions in this file.
     generator_functions: FxHashSet<FileScopeId>,

crates/ty_python_semantic/src/semantic_index/builder.rs

@@ -115,7 +115,7 @@ pub(super) struct SemanticIndexBuilder<'db, 'ast> {
     generator_functions: FxHashSet<FileScopeId>,
     eager_snapshots: FxHashMap<EagerSnapshotKey, ScopedEagerSnapshotId>,
     /// Errors collected by the `semantic_checker`.
-    semantic_syntax_errors: RefCell<thin_vec::ThinVec<SemanticSyntaxError>>,
+    semantic_syntax_errors: RefCell<Vec<SemanticSyntaxError>>,
 }
 
 impl<'db, 'ast> SemanticIndexBuilder<'db, 'ast> {
@@ -1063,7 +1063,7 @@ impl<'db, 'ast> SemanticIndexBuilder<'db, 'ast> {
             imported_modules: Arc::new(self.imported_modules),
             has_future_annotations: self.has_future_annotations,
             eager_snapshots: self.eager_snapshots,
-            semantic_syntax_errors: self.semantic_syntax_errors.into_inner().into(),
+            semantic_syntax_errors: self.semantic_syntax_errors.into_inner(),
             generator_functions: self.generator_functions,
         }
     }

crates/ty_python_semantic/src/semantic_index/place.rs

@@ -10,13 +10,13 @@ use ruff_index::{IndexVec, newtype_index};
 use ruff_python_ast as ast;
 use ruff_python_ast::name::Name;
 use rustc_hash::FxHasher;
+use smallvec::{SmallVec, smallvec};
 
 use crate::Db;
 use crate::ast_node_ref::AstNodeRef;
 use crate::node_key::NodeKey;
 use crate::semantic_index::reachability_constraints::ScopedReachabilityConstraintId;
 use crate::semantic_index::{PlaceSet, SemanticIndex, semantic_index};
-use crate::util::get_size::ThinVecSized;
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash, get_size2::GetSize)]
 pub(crate) enum PlaceExprSubSegment {
@@ -41,7 +41,7 @@ impl PlaceExprSubSegment {
 #[derive(Eq, PartialEq, Debug, get_size2::GetSize)]
 pub struct PlaceExpr {
     root_name: Name,
-    sub_segments: ThinVecSized<PlaceExprSubSegment>,
+    sub_segments: SmallVec<[PlaceExprSubSegment; 1]>,
 }
 
 impl std::fmt::Display for PlaceExpr {
@@ -165,7 +165,7 @@ impl PlaceExpr {
     pub(crate) fn name(name: Name) -> Self {
         Self {
             root_name: name,
-            sub_segments: ThinVecSized::new(),
+            sub_segments: smallvec![],
         }
     }
 
@@ -230,9 +230,7 @@ impl std::fmt::Display for PlaceExprWithFlags {
 }
 
 impl PlaceExprWithFlags {
-    pub(crate) fn new(mut expr: PlaceExpr) -> Self {
-        expr.sub_segments.shrink_to_fit();
-
+    pub(crate) fn new(expr: PlaceExpr) -> Self {
         PlaceExprWithFlags {
             expr,
             flags: PlaceFlags::empty(),

crates/ty_python_semantic/src/semantic_index/use_def/place_state.rs

@@ -71,12 +71,16 @@ impl ScopedDefinitionId {
     }
 }
 
+/// Can keep inline this many live bindings or declarations per place at a given time; more will
+/// go to heap.
+const INLINE_DEFINITIONS_PER_PLACE: usize = 4;
+
 /// Live declarations for a single place at some point in control flow, with their
 /// corresponding reachability constraints.
 #[derive(Clone, Debug, Default, PartialEq, Eq, salsa::Update, get_size2::GetSize)]
 pub(super) struct Declarations {
     /// A list of live declarations for this place, sorted by their `ScopedDefinitionId`
-    live_declarations: SmallVec<[LiveDeclaration; 2]>,
+    live_declarations: SmallVec<[LiveDeclaration; INLINE_DEFINITIONS_PER_PLACE]>,
 }
 
 /// One of the live declarations for a single place at some point in control flow.
@@ -195,7 +199,7 @@ pub(super) struct Bindings {
     /// "unbound" binding.
     unbound_narrowing_constraint: Option<ScopedNarrowingConstraint>,
     /// A list of live bindings for this place, sorted by their `ScopedDefinitionId`
-    live_bindings: SmallVec<[LiveBinding; 2]>,
+    live_bindings: SmallVec<[LiveBinding; INLINE_DEFINITIONS_PER_PLACE]>,
 }
 
 impl Bindings {

crates/ty_python_semantic/src/types.rs

@@ -6,6 +6,7 @@ use std::slice::Iter;
 
 use bitflags::bitflags;
 use call::{CallDunderError, CallError, CallErrorKind};
+use compact_str::{CompactString, ToCompactString};
 use context::InferContext;
 use diagnostic::{
     INVALID_CONTEXT_MANAGER, INVALID_SUPER_ARGUMENT, NOT_ITERABLE, POSSIBLY_UNBOUND_IMPLICIT_CALL,
@@ -16,6 +17,7 @@ use ruff_db::files::File;
 use ruff_python_ast::name::Name;
 use ruff_python_ast::{self as ast, AnyNodeRef};
 use ruff_text_size::{Ranged, TextRange};
+use salsa::plumbing::interned::Lookup;
 use type_ordering::union_or_intersection_elements_ordering;
 
 pub(crate) use self::builder::{IntersectionBuilder, UnionBuilder};
@@ -93,7 +95,7 @@ mod definition;
 #[cfg(test)]
 mod property_tests;
 
-pub fn check_types(db: &dyn Db, file: File) -> thin_vec::ThinVec<Diagnostic> {
+pub fn check_types(db: &dyn Db, file: File) -> Vec<Diagnostic> {
     let _span = tracing::trace_span!("check_types", ?file).entered();
 
     tracing::debug!("Checking file '{path}'", path = file.path(db));
@@ -938,7 +940,7 @@ impl<'db> Type<'db> {
     }
 
     pub fn string_literal(db: &'db dyn Db, string: &str) -> Self {
-        Self::StringLiteral(StringLiteralType::new(db, string))
+        Self::StringLiteral(StringLiteralType::new(db, StringLiteralValue::new(string)))
     }
 
     pub fn bytes_literal(db: &'db dyn Db, bytes: &[u8]) -> Self {
@@ -5576,7 +5578,7 @@ impl<'db> Type<'db> {
             Type::SpecialForm(special_form) => Type::string_literal(db, special_form.repr()),
             Type::KnownInstance(known_instance) => Type::StringLiteral(StringLiteralType::new(
                 db,
-                known_instance.repr(db).to_string().into_boxed_str(),
+                StringLiteralValue::from(known_instance.repr(db).to_compact_string()),
             )),
             // TODO: handle more complex types
             _ => KnownClass::Str.to_instance(db),
@@ -5598,7 +5600,7 @@ impl<'db> Type<'db> {
             Type::SpecialForm(special_form) => Type::string_literal(db, special_form.repr()),
             Type::KnownInstance(known_instance) => Type::StringLiteral(StringLiteralType::new(
                 db,
-                known_instance.repr(db).to_string().into_boxed_str(),
+                StringLiteralValue::from(known_instance.repr(db).to_compact_string()),
             )),
             // TODO: handle more complex types
             _ => KnownClass::Str.to_instance(db),
@@ -8280,7 +8282,7 @@ impl<'db> IntersectionType<'db> {
 #[derive(PartialOrd, Ord)]
 pub struct StringLiteralType<'db> {
     #[returns(deref)]
-    value: Box<str>,
+    value: StringLiteralValue,
 }
 
 // The Salsa heap is tracked separately.
@@ -8297,7 +8299,41 @@ impl<'db> StringLiteralType<'db> {
     pub(crate) fn iter_each_char(self, db: &'db dyn Db) -> impl Iterator<Item = Self> {
         self.value(db)
             .chars()
-            .map(|c| StringLiteralType::new(db, c.to_string().into_boxed_str()))
+            .map(|c| StringLiteralType::new(db, StringLiteralValue::from_char(c)))
+    }
+}
+
+/// Newtype wrapper around `compact_str`'s `CompactString` so that `Lookup` can be implemented for it.
+#[derive(PartialEq, Eq, Debug, Clone, Hash, Ord, PartialOrd, get_size2::GetSize)]
+pub struct StringLiteralValue(CompactString);
+
+impl StringLiteralValue {
+    fn new(value: impl AsRef<str>) -> Self {
+        StringLiteralValue(CompactString::new(value.as_ref()))
+    }
+
+    fn from_char(c: char) -> Self {
+        StringLiteralValue(c.to_compact_string())
+    }
+}
+
+impl Lookup<StringLiteralValue> for &str {
+    fn into_owned(self) -> StringLiteralValue {
+        StringLiteralValue(CompactString::new(self))
+    }
+}
+
+impl std::ops::Deref for StringLiteralValue {
+    type Target = str;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl From<compact_str::CompactString> for StringLiteralValue {
+    fn from(value: compact_str::CompactString) -> Self {
+        StringLiteralValue(value)
     }
 }
 

crates/ty_python_semantic/src/types/diagnostic.rs

@@ -18,7 +18,6 @@ use crate::types::string_annotation::{
 use crate::types::tuple::TupleType;
 use crate::types::{SpecialFormType, Type, protocol_class::ProtocolClassLiteral};
 use crate::util::diagnostics::format_enumeration;
-use crate::util::get_size::ThinVecSized;
 use crate::{Db, FxIndexMap, Module, ModuleName, Program, declare_lint};
 use itertools::Itertools;
 use ruff_db::diagnostic::{Annotation, Diagnostic, Severity, SubDiagnostic};
@@ -1615,7 +1614,7 @@ declare_lint! {
 /// A collection of type check diagnostics.
 #[derive(Default, Eq, PartialEq, get_size2::GetSize)]
 pub struct TypeCheckDiagnostics {
-    diagnostics: ThinVecSized<Diagnostic>,
+    diagnostics: Vec<Diagnostic>,
     used_suppressions: FxHashSet<FileSuppressionId>,
 }
 
@@ -1650,8 +1649,8 @@ impl TypeCheckDiagnostics {
         self.diagnostics.shrink_to_fit();
     }
 
-    pub(crate) fn into_vec(self) -> thin_vec::ThinVec<Diagnostic> {
-        self.diagnostics.into_inner()
+    pub(crate) fn into_vec(self) -> Vec<Diagnostic> {
+        self.diagnostics
     }
 
     pub fn iter(&self) -> std::slice::Iter<'_, Diagnostic> {
@@ -1667,7 +1666,7 @@ impl std::fmt::Debug for TypeCheckDiagnostics {
 
 impl IntoIterator for TypeCheckDiagnostics {
     type Item = Diagnostic;
-    type IntoIter = thin_vec::IntoIter<Diagnostic>;
+    type IntoIter = std::vec::IntoIter<Diagnostic>;
 
     fn into_iter(self) -> Self::IntoIter {
         self.diagnostics.into_iter()

crates/ty_python_semantic/src/util/get_size.rs

@@ -1,4 +1,3 @@
-use std::ops::{Deref, DerefMut};
 use std::sync::Arc;
 
 use get_size2::GetSize;
@@ -14,105 +13,3 @@ where
 {
     T::get_heap_size(&**arc)
 }
-
-#[derive(Clone, Hash, PartialEq, Eq)]
-pub(crate) struct ThinVecSized<T>(thin_vec::ThinVec<T>);
-
-impl<T> ThinVecSized<T> {
-    pub(crate) fn into_inner(self) -> thin_vec::ThinVec<T> {
-        self.0
-    }
-
-    pub(crate) fn new() -> Self {
-        Self(thin_vec::ThinVec::new())
-    }
-}
-
-impl<T> Default for ThinVecSized<T> {
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
-#[allow(unsafe_code)]
-unsafe impl<T> salsa::Update for ThinVecSized<T>
-where
-    T: salsa::Update,
-{
-    unsafe fn maybe_update(old_pointer: *mut Self, new_value: Self) -> bool {
-        let old: &mut Self = unsafe { &mut *old_pointer };
-
-        unsafe { salsa::Update::maybe_update(&raw mut old.0, new_value.0) }
-    }
-}
-
-impl<T> std::fmt::Debug for ThinVecSized<T>
-where
-    T: std::fmt::Debug,
-{
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        self.0.fmt(f)
-    }
-}
-
-impl<T> From<thin_vec::ThinVec<T>> for ThinVecSized<T> {
-    fn from(vec: thin_vec::ThinVec<T>) -> Self {
-        Self(vec)
-    }
-}
-
-impl<T> Deref for ThinVecSized<T> {
-    type Target = thin_vec::ThinVec<T>;
-
-    fn deref(&self) -> &Self::Target {
-        &self.0
-    }
-}
-
-impl<T> DerefMut for ThinVecSized<T> {
-    fn deref_mut(&mut self) -> &mut Self::Target {
-        &mut self.0
-    }
-}
-
-impl<T> GetSize for ThinVecSized<T>
-where
-    T: GetSize,
-{
-    fn get_heap_size(&self) -> usize {
-        let mut total = 0;
-        for v in self {
-            total += GetSize::get_size(v);
-        }
-        let additional: usize = self.capacity() - self.len();
-        total += additional * T::get_stack_size();
-        total
-    }
-}
-
-impl<'a, T> IntoIterator for &'a ThinVecSized<T> {
-    type Item = &'a T;
-    type IntoIter = std::slice::Iter<'a, T>;
-
-    fn into_iter(self) -> Self::IntoIter {
-        self.0.iter()
-    }
-}
-
-impl<'a, T> IntoIterator for &'a mut ThinVecSized<T> {
-    type Item = &'a mut T;
-    type IntoIter = std::slice::IterMut<'a, T>;
-
-    fn into_iter(self) -> Self::IntoIter {
-        self.0.iter_mut()
-    }
-}
-
-impl<T> IntoIterator for ThinVecSized<T> {
-    type Item = T;
-    type IntoIter = thin_vec::IntoIter<T>;
-
-    fn into_iter(self) -> Self::IntoIter {
-        self.0.into_iter()
-    }
-}

crates/ty_server/Cargo.toml

@@ -23,7 +23,6 @@ ty_python_semantic = { workspace = true }
 ty_vendored = { workspace = true }
 
 anyhow = { workspace = true }
-bitflags = { workspace = true }
 crossbeam = { workspace = true }
 jod-thread = { workspace = true }
 lsp-server = { workspace = true }

crates/ty_server/src/server.rs

@@ -21,8 +21,8 @@ mod schedule;
 
 use crate::session::client::Client;
 pub(crate) use api::Error;
-pub(crate) use api::publish_settings_diagnostics;
 pub(crate) use main_loop::{Action, ConnectionSender, Event, MainLoopReceiver, MainLoopSender};
+
 pub(crate) type Result<T> = std::result::Result<T, api::Error>;
 
 pub(crate) struct Server {

crates/ty_server/src/server/api.rs

@@ -17,7 +17,6 @@ mod traits;
 use self::traits::{NotificationHandler, RequestHandler};
 use super::{Result, schedule::BackgroundSchedule};
 use crate::session::client::Client;
-pub(crate) use diagnostics::publish_settings_diagnostics;
 use ruff_db::panic::PanicError;
 
 /// Processes a request from the client to the server.

crates/ty_server/src/server/api/diagnostics.rs

@@ -8,13 +8,11 @@ use rustc_hash::FxHashMap;
 use ruff_db::diagnostic::{Annotation, Severity, SubDiagnostic};
 use ruff_db::files::FileRange;
 use ruff_db::source::{line_index, source_text};
-use ruff_db::system::SystemPathBuf;
 use ty_project::{Db, ProjectDatabase};
 
 use crate::document::{DocumentKey, FileRangeExt, ToRangeExt};
 use crate::session::DocumentSnapshot;
 use crate::session::client::Client;
-use crate::system::{AnySystemPath, file_to_url};
 use crate::{PositionEncoding, Session};
 
 /// Represents the diagnostics for a text document or a notebook document.
@@ -66,7 +64,7 @@ pub(super) fn clear_diagnostics(key: &DocumentKey, client: &Client) {
 ///
 /// [publish diagnostics notification]: https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocument_publishDiagnostics
 pub(super) fn publish_diagnostics(session: &Session, key: &DocumentKey, client: &Client) {
-    if session.client_capabilities().supports_pull_diagnostics() {
+    if session.client_capabilities().pull_diagnostics {
         return;
     }
 
@@ -111,82 +109,6 @@ pub(super) fn publish_diagnostics(session: &Session, key: &DocumentKey, client:
     }
 }
 
-/// Publishes settings diagnostics for all the project at the given path
-/// using the [publish diagnostics notification].
-///
-/// [publish diagnostics notification]: https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocument_publishDiagnostics
-pub(crate) fn publish_settings_diagnostics(
-    session: &mut Session,
-    client: &Client,
-    path: SystemPathBuf,
-) {
-    // Don't publish settings diagnostics for workspace that are already doing full diagnostics.
-    //
-    // Note we DO NOT respect the fact that clients support pulls because these are
-    // files they *specifically* won't pull diagnostics from us for, because we don't
-    // claim to be an LSP for them.
-    let has_workspace_diagnostics = session
-        .workspaces()
-        .for_path(&path)
-        .map(|workspace| workspace.settings().diagnostic_mode().is_workspace())
-        .unwrap_or(false);
-    if has_workspace_diagnostics {
-        return;
-    }
-
-    let session_encoding = session.position_encoding();
-    let state = session.project_state_mut(&AnySystemPath::System(path));
-    let db = &state.db;
-    let project = db.project();
-    let settings_diagnostics = project.check_settings(db);
-
-    // We need to send diagnostics if we have non-empty ones, or we have ones to clear.
-    // These will both almost always be empty so this function will almost always be a no-op.
-    if settings_diagnostics.is_empty() && state.untracked_files_with_pushed_diagnostics.is_empty() {
-        return;
-    }
-
-    // Group diagnostics by URL
-    let mut diagnostics_by_url: FxHashMap<Url, Vec<_>> = FxHashMap::default();
-    for diagnostic in settings_diagnostics {
-        if let Some(span) = diagnostic.primary_span() {
-            let file = span.expect_ty_file();
-            let Some(url) = file_to_url(db, file) else {
-                tracing::debug!("Failed to convert file to URL at {}", file.path(db));
-                continue;
-            };
-            diagnostics_by_url.entry(url).or_default().push(diagnostic);
-        }
-    }
-
-    // Record the URLs we're sending non-empty diagnostics for, so we know to clear them
-    // the next time we publish settings diagnostics!
-    let old_untracked = std::mem::replace(
-        &mut state.untracked_files_with_pushed_diagnostics,
-        diagnostics_by_url.keys().cloned().collect(),
-    );
-
-    // Add empty diagnostics for any files that had diagnostics before but don't now.
-    // This will clear them (either the file is no longer relevant to us or fixed!)
-    for url in old_untracked {
-        diagnostics_by_url.entry(url).or_default();
-    }
-    // Send the settings diagnostics!
-    for (url, file_diagnostics) in diagnostics_by_url {
-        // Convert diagnostics to LSP format
-        let lsp_diagnostics = file_diagnostics
-            .into_iter()
-            .map(|diagnostic| to_lsp_diagnostic(db, &diagnostic, session_encoding))
-            .collect::<Vec<_>>();
-
-        client.send_notification::<PublishDiagnostics>(PublishDiagnosticsParams {
-            uri: url,
-            diagnostics: lsp_diagnostics,
-            version: None,
-        });
-    }
-}
-
 pub(super) fn compute_diagnostics(
     db: &ProjectDatabase,
     snapshot: &DocumentSnapshot,

crates/ty_server/src/server/api/notifications/did_change_watched_files.rs

@@ -1,5 +1,5 @@
 use crate::server::Result;
-use crate::server::api::diagnostics::{publish_diagnostics, publish_settings_diagnostics};
+use crate::server::api::diagnostics::publish_diagnostics;
 use crate::server::api::traits::{NotificationHandler, SyncNotificationHandler};
 use crate::session::Session;
 use crate::session::client::Client;
@@ -88,8 +88,7 @@ impl SyncNotificationHandler for DidChangeWatchedFiles {
         for (root, changes) in events_by_db {
             tracing::debug!("Applying changes to `{root}`");
 
-            let result = session.apply_changes(&AnySystemPath::System(root.clone()), changes);
-            publish_settings_diagnostics(session, client, root);
+            let result = session.apply_changes(&AnySystemPath::System(root), changes);
 
             project_changed |= result.project_changed();
         }
@@ -97,7 +96,7 @@ impl SyncNotificationHandler for DidChangeWatchedFiles {
         let client_capabilities = session.client_capabilities();
 
         if project_changed {
-            if client_capabilities.supports_workspace_diagnostic_refresh() {
+            if client_capabilities.diagnostics_refresh {
                 client.send_request::<types::request::WorkspaceDiagnosticRefresh>(
                     session,
                     (),
@@ -108,10 +107,11 @@ impl SyncNotificationHandler for DidChangeWatchedFiles {
                     publish_diagnostics(session, &key, client);
                 }
             }
+
             // TODO: always publish diagnostics for notebook files (since they don't use pull diagnostics)
         }
 
-        if client_capabilities.supports_inlay_hint_refresh() {
+        if client_capabilities.inlay_refresh {
             client.send_request::<types::request::InlayHintRefreshRequest>(session, (), |_, ()| {});
         }
 

crates/ty_server/src/server/api/requests/goto_declaration.rs

@@ -52,7 +52,7 @@ impl BackgroundDocumentRequestHandler for GotoDeclarationRequestHandler {
 
         if snapshot
             .resolved_client_capabilities()
-            .supports_declaration_link()
+            .type_definition_link_support
         {
             let src = Some(ranged.range);
             let links: Vec<_> = ranged

crates/ty_server/src/server/api/requests/goto_definition.rs

@@ -52,7 +52,7 @@ impl BackgroundDocumentRequestHandler for GotoDefinitionRequestHandler {
 
         if snapshot
             .resolved_client_capabilities()
-            .supports_definition_link()
+            .type_definition_link_support
         {
             let src = Some(ranged.range);
             let links: Vec<_> = ranged

crates/ty_server/src/server/api/requests/goto_type_definition.rs

@@ -52,7 +52,7 @@ impl BackgroundDocumentRequestHandler for GotoTypeDefinitionRequestHandler {
 
         if snapshot
             .resolved_client_capabilities()
-            .supports_type_definition_link()
+            .type_definition_link_support
         {
             let src = Some(ranged.range);
             let links: Vec<_> = ranged

crates/ty_server/src/server/api/requests/hover.rs

@@ -52,7 +52,7 @@ impl BackgroundDocumentRequestHandler for HoverRequestHandler {
 
         let (markup_kind, lsp_markup_kind) = if snapshot
             .resolved_client_capabilities()
-            .prefers_markdown_in_hover()
+            .hover_prefer_markdown
         {
             (MarkupKind::Markdown, lsp_types::MarkupKind::Markdown)
         } else {

crates/ty_server/src/server/api/requests/semantic_tokens.rs

@@ -41,7 +41,7 @@ impl BackgroundDocumentRequestHandler for SemanticTokensRequestHandler {
             snapshot.encoding(),
             snapshot
                 .resolved_client_capabilities()
-                .supports_multiline_semantic_tokens(),
+                .semantic_tokens_multiline_support,
         );
 
         Ok(Some(SemanticTokensResult::Tokens(SemanticTokens {

crates/ty_server/src/server/api/requests/semantic_tokens_range.rs

@@ -51,7 +51,7 @@ impl BackgroundDocumentRequestHandler for SemanticTokensRangeRequestHandler {
             snapshot.encoding(),
             snapshot
                 .resolved_client_capabilities()
-                .supports_multiline_semantic_tokens(),
+                .semantic_tokens_multiline_support,
         );
 
         Ok(Some(SemanticTokensRangeResult::Tokens(SemanticTokens {

crates/ty_server/src/server/api/requests/signature_help.rs

@@ -71,7 +71,7 @@ impl BackgroundDocumentRequestHandler for SignatureHelpRequestHandler {
                     .parameters
                     .into_iter()
                     .map(|param| {
-                        let label = if resolved_capabilities.supports_signature_label_offset() {
+                        let label = if resolved_capabilities.signature_label_offset_support {
                             // Find the parameter's offset in the signature label
                             if let Some(start) = sig.label.find(&param.label) {
                                 let encoding = snapshot.encoding();
@@ -114,12 +114,11 @@ impl BackgroundDocumentRequestHandler for SignatureHelpRequestHandler {
                     })
                     .collect();
 
-                let active_parameter =
-                    if resolved_capabilities.supports_signature_active_parameter() {
-                        sig.active_parameter.and_then(|p| u32::try_from(p).ok())
-                    } else {
-                        None
-                    };
+                let active_parameter = if resolved_capabilities.signature_active_parameter_support {
+                    sig.active_parameter.and_then(|p| u32::try_from(p).ok())
+                } else {
+                    None
+                };
 
                 SignatureInformation {
                     label: sig.label,

crates/ty_server/src/session.rs

@@ -21,7 +21,6 @@ pub(crate) use self::index::DocumentQuery;
 pub(crate) use self::options::{AllOptions, ClientOptions, DiagnosticMode};
 pub(crate) use self::settings::ClientSettings;
 use crate::document::{DocumentKey, DocumentVersion, NotebookDocument};
-use crate::server::publish_settings_diagnostics;
 use crate::session::client::Client;
 use crate::session::request_queue::RequestQueue;
 use crate::system::{AnySystemPath, LSPSystem};
@@ -50,7 +49,7 @@ pub(crate) struct Session {
     workspaces: Workspaces,
 
     /// The projects across all workspaces.
-    projects: BTreeMap<SystemPathBuf, ProjectState>,
+    projects: BTreeMap<SystemPathBuf, ProjectDatabase>,
 
     /// The project to use for files outside any workspace. For example, if the user
     /// opens the project `<home>/my_project` in VS code but they then opens a Python file from their Desktop.
@@ -63,7 +62,7 @@ pub(crate) struct Session {
     position_encoding: PositionEncoding,
 
     /// Tracks what LSP features the client supports and doesn't support.
-    resolved_client_capabilities: ResolvedClientCapabilities,
+    resolved_client_capabilities: Arc<ResolvedClientCapabilities>,
 
     /// Tracks the pending requests between client and server.
     request_queue: RequestQueue,
@@ -74,25 +73,6 @@ pub(crate) struct Session {
     deferred_messages: VecDeque<Message>,
 }
 
-/// LSP State for a Project
-pub(crate) struct ProjectState {
-    pub(crate) db: ProjectDatabase,
-    /// Files that we have outstanding otherwise-untracked pushed diagnostics for.
-    ///
-    /// In `CheckMode::OpenFiles` we still read some files that the client hasn't
-    /// told us to open. Notably settings files like `pyproject.toml`. In this
-    /// mode the client will never pull diagnostics for that file, and because
-    /// the file isn't formally "open" we also don't have a reliable signal to
-    /// refresh diagnostics for it either.
-    ///
-    /// However diagnostics for those files include things like "you typo'd your
-    /// configuration for the LSP itself", so it's really important that we tell
-    /// the user about them! So we remember which ones we have emitted diagnostics
-    /// for so that we can clear the diagnostics for all of them before we go
-    /// to update any of them.
-    pub(crate) untracked_files_with_pushed_diagnostics: Vec<Url>,
-}
-
 impl Session {
     pub(crate) fn new(
         client_capabilities: &ClientCapabilities,
@@ -114,7 +94,9 @@ impl Session {
             index: Some(index),
             default_project: DefaultProject::new(),
             projects: BTreeMap::new(),
-            resolved_client_capabilities: ResolvedClientCapabilities::new(client_capabilities),
+            resolved_client_capabilities: Arc::new(ResolvedClientCapabilities::new(
+                client_capabilities,
+            )),
             request_queue: RequestQueue::new(),
             shutdown_requested: false,
         })
@@ -188,7 +170,17 @@ impl Session {
     ///
     /// If the path is a virtual path, it will return the first project database in the session.
     pub(crate) fn project_db(&self, path: &AnySystemPath) -> &ProjectDatabase {
-        &self.project_state(path).db
+        match path {
+            AnySystemPath::System(system_path) => self
+                .project_db_for_path(system_path)
+                .unwrap_or_else(|| self.default_project.get(self.index.as_ref())),
+            AnySystemPath::SystemVirtual(_virtual_path) => {
+                // TODO: Currently, ty only supports single workspace but we need to figure out
+                // which project should this virtual path belong to when there are multiple
+                // projects: https://github.com/astral-sh/ty/issues/794
+                self.projects.iter().next().map(|(_, db)| db).unwrap()
+            }
+        }
     }
 
     /// Returns a mutable reference to the project's [`ProjectDatabase`] in which the given `path`
@@ -198,7 +190,20 @@ impl Session {
     ///
     /// [`project_db`]: Session::project_db
     pub(crate) fn project_db_mut(&mut self, path: &AnySystemPath) -> &mut ProjectDatabase {
-        &mut self.project_state_mut(path).db
+        match path {
+            AnySystemPath::System(system_path) => self
+                .projects
+                .range_mut(..=system_path.to_path_buf())
+                .next_back()
+                .map(|(_, db)| db)
+                .unwrap_or_else(|| self.default_project.get_mut(self.index.as_ref())),
+            AnySystemPath::SystemVirtual(_virtual_path) => {
+                // TODO: Currently, ty only supports single workspace but we need to figure out
+                // which project should this virtual path belong to when there are multiple
+                // projects: https://github.com/astral-sh/ty/issues/794
+                self.projects.iter_mut().next().map(|(_, db)| db).unwrap()
+            }
+        }
     }
 
     /// Returns a reference to the project's [`ProjectDatabase`] corresponding to the given path, if
@@ -207,70 +212,10 @@ impl Session {
         &self,
         path: impl AsRef<SystemPath>,
     ) -> Option<&ProjectDatabase> {
-        self.project_state_for_path(path).map(|state| &state.db)
-    }
-
-    /// Returns a reference to the project's [`ProjectState`] in which the given `path` belongs.
-    ///
-    /// If the path is a system path, it will return the project database that is closest to the
-    /// given path, or the default project if no project is found for the path.
-    ///
-    /// If the path is a virtual path, it will return the first project database in the session.
-    pub(crate) fn project_state(&self, path: &AnySystemPath) -> &ProjectState {
-        match path {
-            AnySystemPath::System(system_path) => self
-                .project_state_for_path(system_path)
-                .unwrap_or_else(|| self.default_project.get(self.index.as_ref())),
-            AnySystemPath::SystemVirtual(_virtual_path) => {
-                // TODO: Currently, ty only supports single workspace but we need to figure out
-                // which project should this virtual path belong to when there are multiple
-                // projects: https://github.com/astral-sh/ty/issues/794
-                self.projects
-                    .iter()
-                    .next()
-                    .map(|(_, project)| project)
-                    .unwrap()
-            }
-        }
-    }
-
-    /// Returns a mutable reference to the project's [`ProjectState`] in which the given `path`
-    /// belongs.
-    ///
-    /// Refer to [`project_db`] for more details on how the project is selected.
-    ///
-    /// [`project_db`]: Session::project_db
-    pub(crate) fn project_state_mut(&mut self, path: &AnySystemPath) -> &mut ProjectState {
-        match path {
-            AnySystemPath::System(system_path) => self
-                .projects
-                .range_mut(..=system_path.to_path_buf())
-                .next_back()
-                .map(|(_, project)| project)
-                .unwrap_or_else(|| self.default_project.get_mut(self.index.as_ref())),
-            AnySystemPath::SystemVirtual(_virtual_path) => {
-                // TODO: Currently, ty only supports single workspace but we need to figure out
-                // which project should this virtual path belong to when there are multiple
-                // projects: https://github.com/astral-sh/ty/issues/794
-                self.projects
-                    .iter_mut()
-                    .next()
-                    .map(|(_, project)| project)
-                    .unwrap()
-            }
-        }
-    }
-
-    /// Returns a reference to the project's [`ProjectState`] corresponding to the given path, if
-    /// any.
-    pub(crate) fn project_state_for_path(
-        &self,
-        path: impl AsRef<SystemPath>,
-    ) -> Option<&ProjectState> {
         self.projects
             .range(..=path.as_ref().to_path_buf())
             .next_back()
-            .map(|(_, project)| project)
+            .map(|(_, db)| db)
     }
 
     pub(crate) fn apply_changes(
@@ -294,13 +239,6 @@ impl Session {
     ///
     /// This iterator will only yield the default project database if it has been used.
     fn projects_mut(&mut self) -> impl Iterator<Item = &'_ mut ProjectDatabase> + '_ {
-        self.project_states_mut().map(|project| &mut project.db)
-    }
-
-    /// Returns a mutable iterator over all projects that have been initialized to this point.
-    ///
-    /// This iterator will only yield the default project if it has been used.
-    pub(crate) fn project_states_mut(&mut self) -> impl Iterator<Item = &'_ mut ProjectState> + '_ {
         let default_project = self.default_project.try_get_mut();
         self.projects.values_mut().chain(default_project)
     }
@@ -346,8 +284,10 @@ impl Session {
                     ProjectDatabase::new(metadata, system.clone())
                 });
 
-            let (root, db) = match project {
-                Ok(db) => (root, db),
+            match project {
+                Ok(project) => {
+                    self.projects.insert(root, project);
+                }
                 Err(err) => {
                     tracing::error!(
                         "Failed to create project for `{root}`: {err:#}. Falling back to default settings"
@@ -362,29 +302,16 @@ impl Session {
                             .context("Failed to convert default options to metadata")
                             .and_then(|metadata| ProjectDatabase::new(metadata, system))
                             .expect("Default configuration to be valid");
-                    let default_root = db_with_default_settings
-                        .project()
-                        .root(&db_with_default_settings)
-                        .to_path_buf();
 
-                    (default_root, db_with_default_settings)
+                    self.projects.insert(
+                        db_with_default_settings
+                            .project()
+                            .root(&db_with_default_settings)
+                            .to_path_buf(),
+                        db_with_default_settings,
+                    );
                 }
-            };
-
-            // Carry forward diagnostic state if any exists
-            let previous = self.projects.remove(&root);
-            let untracked = previous
-                .map(|state| state.untracked_files_with_pushed_diagnostics)
-                .unwrap_or_default();
-            self.projects.insert(
-                root.clone(),
-                ProjectState {
-                    db,
-                    untracked_files_with_pushed_diagnostics: untracked,
-                },
-            );
-
-            publish_settings_diagnostics(self, client, root);
+            }
         }
 
         assert!(
@@ -405,7 +332,7 @@ impl Session {
     pub(crate) fn take_document_snapshot(&self, url: Url) -> DocumentSnapshot {
         let index = self.index();
         DocumentSnapshot {
-            resolved_client_capabilities: self.resolved_client_capabilities,
+            resolved_client_capabilities: self.resolved_client_capabilities.clone(),
             client_settings: index.global_settings(),
             position_encoding: self.position_encoding,
             document_query_result: self
@@ -418,12 +345,7 @@ impl Session {
     /// Creates a snapshot of the current state of the [`Session`].
     pub(crate) fn take_session_snapshot(&self) -> SessionSnapshot {
         SessionSnapshot {
-            projects: self
-                .projects
-                .values()
-                .map(|project| &project.db)
-                .cloned()
-                .collect(),
+            projects: self.projects.values().cloned().collect(),
             index: self.index.clone().unwrap(),
             position_encoding: self.position_encoding,
         }
@@ -510,17 +432,13 @@ impl Session {
         }
     }
 
-    pub(crate) fn client_capabilities(&self) -> ResolvedClientCapabilities {
-        self.resolved_client_capabilities
+    pub(crate) fn client_capabilities(&self) -> &ResolvedClientCapabilities {
+        &self.resolved_client_capabilities
     }
 
     pub(crate) fn global_settings(&self) -> Arc<ClientSettings> {
         self.index().global_settings()
     }
-
-    pub(crate) fn position_encoding(&self) -> PositionEncoding {
-        self.position_encoding
-    }
 }
 
 /// A guard that holds the only reference to the index and allows modifying it.
@@ -565,7 +483,7 @@ impl Drop for MutIndexGuard<'_> {
 /// An immutable snapshot of [`Session`] that references a specific document.
 #[derive(Debug)]
 pub(crate) struct DocumentSnapshot {
-    resolved_client_capabilities: ResolvedClientCapabilities,
+    resolved_client_capabilities: Arc<ResolvedClientCapabilities>,
     client_settings: Arc<ClientSettings>,
     position_encoding: PositionEncoding,
     document_query_result: Result<DocumentQuery, DocumentQueryError>,
@@ -573,8 +491,8 @@ pub(crate) struct DocumentSnapshot {
 
 impl DocumentSnapshot {
     /// Returns the resolved client capabilities that were captured during initialization.
-    pub(crate) fn resolved_client_capabilities(&self) -> ResolvedClientCapabilities {
-        self.resolved_client_capabilities
+    pub(crate) fn resolved_client_capabilities(&self) -> &ResolvedClientCapabilities {
+        &self.resolved_client_capabilities
     }
 
     /// Returns the position encoding that was negotiated during initialization.
@@ -738,14 +656,14 @@ impl Workspace {
 ///    We really want that to be the actual project database and not our fallback database.
 /// 2. The logs when the server starts can be confusing if it once shows it uses Python X (for the default db)
 ///    but then has another log that it uses Python Y (for the actual project db).
-struct DefaultProject(std::sync::OnceLock<ProjectState>);
+struct DefaultProject(std::sync::OnceLock<ProjectDatabase>);
 
 impl DefaultProject {
     pub(crate) fn new() -> Self {
         DefaultProject(std::sync::OnceLock::new())
     }
 
-    pub(crate) fn get(&self, index: Option<&Arc<Index>>) -> &ProjectState {
+    pub(crate) fn get(&self, index: Option<&Arc<Index>>) -> &ProjectDatabase {
         self.0.get_or_init(|| {
             tracing::info!("Initialize default project");
 
@@ -756,14 +674,11 @@ impl DefaultProject {
                 None,
             )
             .unwrap();
-            ProjectState {
-                db: ProjectDatabase::new(metadata, system).unwrap(),
-                untracked_files_with_pushed_diagnostics: Vec::new(),
-            }
+            ProjectDatabase::new(metadata, system).unwrap()
         })
     }
 
-    pub(crate) fn get_mut(&mut self, index: Option<&Arc<Index>>) -> &mut ProjectState {
+    pub(crate) fn get_mut(&mut self, index: Option<&Arc<Index>>) -> &mut ProjectDatabase {
         let _ = self.get(index);
 
         // SAFETY: The `OnceLock` is guaranteed to be initialized at this point because
@@ -771,7 +686,7 @@ impl DefaultProject {
         self.0.get_mut().unwrap()
     }
 
-    pub(crate) fn try_get_mut(&mut self) -> Option<&mut ProjectState> {
+    pub(crate) fn try_get_mut(&mut self) -> Option<&mut ProjectDatabase> {
         self.0.get_mut()
     }
 }

crates/ty_server/src/session/capabilities.rs

@@ -1,121 +1,87 @@
 use lsp_types::{ClientCapabilities, MarkupKind};
 
-bitflags::bitflags! {
-    /// Represents the resolved client capabilities for the language server.
+#[derive(Debug, Clone, PartialEq, Eq, Default)]
+#[expect(clippy::struct_excessive_bools)]
+pub(crate) struct ResolvedClientCapabilities {
+    pub(crate) code_action_deferred_edit_resolution: bool,
+    pub(crate) apply_edit: bool,
+    pub(crate) document_changes: bool,
+    pub(crate) diagnostics_refresh: bool,
+    pub(crate) inlay_refresh: bool,
+
+    /// Whether [pull diagnostics] is supported.
     ///
-    /// This tracks various capabilities that the client supports.
-    #[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
-    pub(crate) struct ResolvedClientCapabilities: u32 {
-        const WORKSPACE_DIAGNOSTIC_REFRESH = 1 << 0;
-        const INLAY_HINT_REFRESH = 1 << 1;
-        const PULL_DIAGNOSTICS = 1 << 2;
-        const TYPE_DEFINITION_LINK_SUPPORT = 1 << 3;
-        const DEFINITION_LINK_SUPPORT = 1 << 4;
-        const DECLARATION_LINK_SUPPORT = 1 << 5;
-        const PREFER_MARKDOWN_IN_HOVER = 1 << 6;
-        const MULTILINE_SEMANTIC_TOKENS = 1 << 7;
-        const SIGNATURE_LABEL_OFFSET_SUPPORT = 1 << 8;
-        const SIGNATURE_ACTIVE_PARAMETER_SUPPORT = 1 << 9;
-    }
+    /// [pull diagnostics]: https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocument_pullDiagnostics
+    pub(crate) pull_diagnostics: bool,
+
+    /// Whether `textDocument.typeDefinition.linkSupport` is `true`
+    pub(crate) type_definition_link_support: bool,
+
+    /// `true`, if the first markup kind in `textDocument.hover.contentFormat` is `Markdown`
+    pub(crate) hover_prefer_markdown: bool,
+
+    /// Whether the client supports multiline semantic tokens
+    pub(crate) semantic_tokens_multiline_support: bool,
+
+    /// Whether the client supports signature label offsets in signature help
+    pub(crate) signature_label_offset_support: bool,
+
+    /// Whether the client supports per-signature active parameter in signature help
+    pub(crate) signature_active_parameter_support: bool,
 }
 
 impl ResolvedClientCapabilities {
-    /// Returns `true` if the client supports workspace diagnostic refresh.
-    pub(crate) const fn supports_workspace_diagnostic_refresh(self) -> bool {
-        self.contains(Self::WORKSPACE_DIAGNOSTIC_REFRESH)
-    }
-
-    /// Returns `true` if the client supports inlay hint refresh.
-    pub(crate) const fn supports_inlay_hint_refresh(self) -> bool {
-        self.contains(Self::INLAY_HINT_REFRESH)
-    }
-
-    /// Returns `true` if the client supports pull diagnostics.
-    pub(crate) const fn supports_pull_diagnostics(self) -> bool {
-        self.contains(Self::PULL_DIAGNOSTICS)
-    }
-
-    /// Returns `true` if the client supports definition links in goto type definition.
-    pub(crate) const fn supports_type_definition_link(self) -> bool {
-        self.contains(Self::TYPE_DEFINITION_LINK_SUPPORT)
-    }
-
-    /// Returns `true` if the client supports definition links in goto definition.
-    pub(crate) const fn supports_definition_link(self) -> bool {
-        self.contains(Self::DEFINITION_LINK_SUPPORT)
-    }
-
-    /// Returns `true` if the client supports definition links in goto declaration.
-    pub(crate) const fn supports_declaration_link(self) -> bool {
-        self.contains(Self::DECLARATION_LINK_SUPPORT)
-    }
-
-    /// Returns `true` if the client prefers markdown in hover responses.
-    pub(crate) const fn prefers_markdown_in_hover(self) -> bool {
-        self.contains(Self::PREFER_MARKDOWN_IN_HOVER)
-    }
-
-    /// Returns `true` if the client supports multiline semantic tokens.
-    pub(crate) const fn supports_multiline_semantic_tokens(self) -> bool {
-        self.contains(Self::MULTILINE_SEMANTIC_TOKENS)
-    }
-
-    /// Returns `true` if the client supports signature label offsets in signature help.
-    pub(crate) const fn supports_signature_label_offset(self) -> bool {
-        self.contains(Self::SIGNATURE_LABEL_OFFSET_SUPPORT)
-    }
-
-    /// Returns `true` if the client supports per-signature active parameter in signature help.
-    pub(crate) const fn supports_signature_active_parameter(self) -> bool {
-        self.contains(Self::SIGNATURE_ACTIVE_PARAMETER_SUPPORT)
-    }
-
     pub(super) fn new(client_capabilities: &ClientCapabilities) -> Self {
-        let mut flags = Self::empty();
+        let code_action_settings = client_capabilities
+            .text_document
+            .as_ref()
+            .and_then(|doc_settings| doc_settings.code_action.as_ref());
+        let code_action_data_support = code_action_settings
+            .and_then(|code_action_settings| code_action_settings.data_support)
+            .unwrap_or_default();
+        let code_action_edit_resolution = code_action_settings
+            .and_then(|code_action_settings| code_action_settings.resolve_support.as_ref())
+            .is_some_and(|resolve_support| resolve_support.properties.contains(&"edit".into()));
 
-        let workspace = client_capabilities.workspace.as_ref();
-        let text_document = client_capabilities.text_document.as_ref();
+        let apply_edit = client_capabilities
+            .workspace
+            .as_ref()
+            .and_then(|workspace| workspace.apply_edit)
+            .unwrap_or_default();
 
-        if workspace
+        let document_changes = client_capabilities
+            .workspace
+            .as_ref()
+            .and_then(|workspace| workspace.workspace_edit.as_ref()?.document_changes)
+            .unwrap_or_default();
+
+        let declaration_link_support = client_capabilities
+            .text_document
+            .as_ref()
+            .and_then(|document| document.type_definition?.link_support)
+            .unwrap_or_default();
+
+        let diagnostics_refresh = client_capabilities
+            .workspace
+            .as_ref()
             .and_then(|workspace| workspace.diagnostics.as_ref()?.refresh_support)
-            .unwrap_or_default()
-        {
-            flags |= Self::WORKSPACE_DIAGNOSTIC_REFRESH;
-        }
+            .unwrap_or_default();
 
-        if workspace
+        let inlay_refresh = client_capabilities
+            .workspace
+            .as_ref()
             .and_then(|workspace| workspace.inlay_hint.as_ref()?.refresh_support)
-            .unwrap_or_default()
-        {
-            flags |= Self::INLAY_HINT_REFRESH;
-        }
+            .unwrap_or_default();
 
-        if text_document.is_some_and(|text_document| text_document.diagnostic.is_some()) {
-            flags |= Self::PULL_DIAGNOSTICS;
-        }
+        let pull_diagnostics = client_capabilities
+            .text_document
+            .as_ref()
+            .and_then(|text_document| text_document.diagnostic.as_ref())
+            .is_some();
 
-        if text_document
-            .and_then(|text_document| text_document.type_definition?.link_support)
-            .unwrap_or_default()
-        {
-            flags |= Self::TYPE_DEFINITION_LINK_SUPPORT;
-        }
-
-        if text_document
-            .and_then(|text_document| text_document.definition?.link_support)
-            .unwrap_or_default()
-        {
-            flags |= Self::DEFINITION_LINK_SUPPORT;
-        }
-
-        if text_document
-            .and_then(|text_document| text_document.declaration?.link_support)
-            .unwrap_or_default()
-        {
-            flags |= Self::DECLARATION_LINK_SUPPORT;
-        }
-
-        if text_document
+        let hover_prefer_markdown = client_capabilities
+            .text_document
+            .as_ref()
             .and_then(|text_document| {
                 Some(
                     text_document
@@ -126,24 +92,18 @@ impl ResolvedClientCapabilities {
                         .contains(&MarkupKind::Markdown),
                 )
             })
-            .unwrap_or_default()
-        {
-            flags |= Self::PREFER_MARKDOWN_IN_HOVER;
-        }
+            .unwrap_or_default();
 
-        if text_document
-            .and_then(|text_document| {
-                text_document
-                    .semantic_tokens
-                    .as_ref()?
-                    .multiline_token_support
-            })
-            .unwrap_or_default()
-        {
-            flags |= Self::MULTILINE_SEMANTIC_TOKENS;
-        }
+        let semantic_tokens_multiline_support = client_capabilities
+            .text_document
+            .as_ref()
+            .and_then(|doc| doc.semantic_tokens.as_ref())
+            .and_then(|semantic_tokens| semantic_tokens.multiline_token_support)
+            .unwrap_or(false);
 
-        if text_document
+        let signature_label_offset_support = client_capabilities
+            .text_document
+            .as_ref()
             .and_then(|text_document| {
                 text_document
                     .signature_help
@@ -154,12 +114,11 @@ impl ResolvedClientCapabilities {
                     .as_ref()?
                     .label_offset_support
             })
-            .unwrap_or_default()
-        {
-            flags |= Self::SIGNATURE_LABEL_OFFSET_SUPPORT;
-        }
+            .unwrap_or_default();
 
-        if text_document
+        let signature_active_parameter_support = client_capabilities
+            .text_document
+            .as_ref()
             .and_then(|text_document| {
                 text_document
                     .signature_help
@@ -168,11 +127,21 @@ impl ResolvedClientCapabilities {
                     .as_ref()?
                     .active_parameter_support
             })
-            .unwrap_or_default()
-        {
-            flags |= Self::SIGNATURE_ACTIVE_PARAMETER_SUPPORT;
-        }
+            .unwrap_or_default();
 
-        flags
+        Self {
+            code_action_deferred_edit_resolution: code_action_data_support
+                && code_action_edit_resolution,
+            apply_edit,
+            document_changes,
+            diagnostics_refresh,
+            inlay_refresh,
+            pull_diagnostics,
+            type_definition_link_support: declaration_link_support,
+            hover_prefer_markdown,
+            semantic_tokens_multiline_support,
+            signature_label_offset_support,
+            signature_active_parameter_support,
+        }
     }
 }

docs/integrations.md

@@ -80,7 +80,7 @@ You can add the following configuration to `.gitlab-ci.yml` to run a `ruff forma
   stage: build
   interruptible: true
   image:
-    name: ghcr.io/astral-sh/ruff:0.12.4-alpine
+    name: ghcr.io/astral-sh/ruff:0.12.3-alpine
   before_script:
     - cd $CI_PROJECT_DIR
     - ruff --version
@@ -106,7 +106,7 @@ Ruff can be used as a [pre-commit](https://pre-commit.com) hook via [`ruff-pre-c
 ```yaml
 - repo: https://github.com/astral-sh/ruff-pre-commit
   # Ruff version.
-  rev: v0.12.4
+  rev: v0.12.3
   hooks:
     # Run the linter.
     - id: ruff
@@ -119,7 +119,7 @@ To enable lint fixes, add the `--fix` argument to the lint hook:
 ```yaml
 - repo: https://github.com/astral-sh/ruff-pre-commit
   # Ruff version.
-  rev: v0.12.4
+  rev: v0.12.3
   hooks:
     # Run the linter.
     - id: ruff
@@ -133,7 +133,7 @@ To avoid running on Jupyter Notebooks, remove `jupyter` from the list of allowed
 ```yaml
 - repo: https://github.com/astral-sh/ruff-pre-commit
   # Ruff version.
-  rev: v0.12.4
+  rev: v0.12.3
   hooks:
     # Run the linter.
     - id: ruff

docs/tutorial.md

@@ -369,7 +369,7 @@ This tutorial has focused on Ruff's command-line interface, but Ruff can also be
 ```yaml
 - repo: https://github.com/astral-sh/ruff-pre-commit
   # Ruff version.
-  rev: v0.12.4
+  rev: v0.12.3
   hooks:
     # Run the linter.
     - id: ruff

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "maturin"
 
 [project]
 name = "ruff"
-version = "0.12.4"
+version = "0.12.3"
 description = "An extremely fast Python linter and code formatter, written in Rust."
 authors = [{ name = "Astral Software Inc.", email = "hey@astral.sh" }]
 readme = "README.md"

scripts/benchmarks/pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "scripts"
-version = "0.12.4"
+version = "0.12.3"
 description = ""
 authors = ["Charles Marsh <charlie.r.marsh@gmail.com>"]