Options: Support #[serde(alias = name)]

Signed-off-by: Micha Reiser <micha@reiser.io>

Cargo.lock

@@ -2259,6 +2259,7 @@ dependencies = [
  "proc-macro2",
  "quote",
  "ruff_python_trivia",
+ "serde_derive_internals 0.29.0",
  "syn 2.0.38",
 ]
 
@@ -2624,7 +2625,7 @@ checksum = "e85e2a16b12bdb763244c69ab79363d71db2b4b918a2def53f80b02e0574b13c"
 dependencies = [
  "proc-macro2",
  "quote",
- "serde_derive_internals",
+ "serde_derive_internals 0.26.0",
  "syn 1.0.109",
 ]
 
@@ -2664,9 +2665,9 @@ checksum = "836fa6a3e1e547f9a2c4040802ec865b5d85f4014efe00555d7090a3dcaa1090"
 
 [[package]]
 name = "serde"
-version = "1.0.188"
+version = "1.0.189"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cf9e0fcba69a370eed61bcf2b728575f726b50b55cba78064753d708ddc7549e"
+checksum = "8e422a44e74ad4001bdc8eede9a4570ab52f71190e9c076d14369f38b9200537"
 dependencies = [
  "serde_derive",
 ]
@@ -2684,9 +2685,9 @@ dependencies = [
 
 [[package]]
 name = "serde_derive"
-version = "1.0.188"
+version = "1.0.189"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4eca7ac642d82aa35b60049a6eccb4be6be75e599bd2e9adb5f875a737654af2"
+checksum = "1e48d1f918009ce3145511378cf68d613e3b3d9137d67272562080d68a2b32d5"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -2704,6 +2705,17 @@ dependencies = [
  "syn 1.0.109",
 ]
 
+[[package]]
+name = "serde_derive_internals"
+version = "0.29.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "330f01ce65a3a5fe59a60c82f3c9a024b573b8a6e875bd233fe5f934e71d54e3"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.38",
+]
+
 [[package]]
 name = "serde_json"
 version = "1.0.107"

Cargo.toml

@@ -34,7 +34,7 @@ quote = { version = "1.0.23" }
 regex = { version = "1.10.2" }
 rustc-hash = { version = "1.1.0" }
 schemars = { version = "0.8.15" }
-serde = { version = "1.0.152", features = ["derive"] }
+serde = { version = "1.0.189", features = ["derive"] }
 serde_json = { version = "1.0.107" }
 shellexpand = { version = "3.0.0" }
 similar = { version = "2.3.0", features = ["inline"] }

crates/ruff_cli/tests/format.rs

@@ -50,6 +50,9 @@ fn format_options() -> Result<()> {
     fs::write(
         &ruff_toml,
         r#"
+tab-size = 8
+line-length = 84
+
 [format]
 indent-style = "tab"
 quote-style = "single"
@@ -64,7 +67,7 @@ line-ending = "cr-lf"
         .arg("-")
         .pass_stdin(r#"
 def foo(arg1, arg2,):
-    print("Shouldn't change quotes")
+    print("Shouldn't change quotes. It exceeds the line width with the tab size 8")
 
 
 if condition:
@@ -76,7 +79,9 @@ if condition:
     exit_code: 0
     ----- stdout -----
     def foo(arg1, arg2):
-    	print("Shouldn't change quotes")
+    	print(
+    		"Shouldn't change quotes. It exceeds the line width with the tab size 8"
+    	)
 
 
     if condition:

crates/ruff_dev/src/generate_options.rs

@@ -1,6 +1,7 @@
 //! Generate a Markdown-compatible listing of configuration options for `pyproject.toml`.
 //!
 //! Used for <https://docs.astral.sh/ruff/settings/>.
+use itertools::Itertools;
 use std::fmt::Write;
 
 use ruff_workspace::options::Options;
@@ -107,6 +108,24 @@ fn emit_field(output: &mut String, name: &str, field: &OptionField, parent_set:
     output.push('\n');
     output.push_str(&format!("**Type**: `{}`\n", field.value_type));
     output.push('\n');
+
+    if !field.aliases.is_empty() {
+        let title = if field.aliases.len() == 1 {
+            "Alias"
+        } else {
+            "Aliases"
+        };
+        output.push_str(&format!(
+            "**{title}**: {}\n",
+            field
+                .aliases
+                .iter()
+                .map(|alias| format!("`{alias}`"))
+                .join(", ")
+        ));
+        output.push('\n');
+    }
+
     output.push_str(&format!(
         "**Example usage**:\n\n```toml\n[tool.ruff{}]\n{}\n```\n",
         if let Some(set_name) = parent_set.name() {

crates/ruff_formatter/src/lib.rs

@@ -95,7 +95,7 @@ impl std::fmt::Display for IndentStyle {
 ///
 /// Determines the visual width of a tab character (`\t`) and the number of
 /// spaces per indent when using [`IndentStyle::Space`].
-#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq, CacheKey)]
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 #[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
 pub struct IndentWidth(NonZeroU8);

crates/ruff_linter/src/line_width.rs

@@ -253,3 +253,9 @@ impl From<NonZeroU8> for TabSize {
         Self(tab_size)
     }
 }
+
+impl From<TabSize> for NonZeroU8 {
+    fn from(value: TabSize) -> Self {
+        value.0
+    }
+}

crates/ruff_macros/Cargo.toml

@@ -16,6 +16,7 @@ doctest = false
 
 [dependencies]
 ruff_python_trivia = { path = "../ruff_python_trivia" }
+serde_derive_internals = "0.29.0"
 
 proc-macro2 = { workspace = true }
 quote = { workspace = true }

crates/ruff_macros/src/config.rs

@@ -1,11 +1,11 @@
-use proc_macro2::TokenTree;
 use quote::{quote, quote_spanned};
+use serde_derive_internals::Ctxt;
 use syn::parse::{Parse, ParseStream};
 use syn::spanned::Spanned;
 use syn::token::Comma;
 use syn::{
     AngleBracketedGenericArguments, Attribute, Data, DataStruct, DeriveInput, ExprLit, Field,
-    Fields, Lit, LitStr, Meta, Path, PathArguments, PathSegment, Token, Type, TypePath,
+    Fields, Lit, LitStr, Path, PathArguments, PathSegment, Token, Type, TypePath,
 };
 
 use ruff_python_trivia::textwrap::dedent;
@@ -38,25 +38,14 @@ pub(crate) fn derive_impl(input: DeriveInput) -> syn::Result<proc_macro2::TokenS
                     .any(|attr| attr.path().is_ident("option_group"))
                 {
                     output.push(handle_option_group(field)?);
-                } else if let Some(serde) = field
-                    .attrs
-                    .iter()
-                    .find(|attr| attr.path().is_ident("serde"))
-                {
+                } else if let Type::Path(ty) = &field.ty {
+                    let serde_field = serde_field_metadata(field)?;
+
                     // If a field has the `serde(flatten)` attribute, flatten the options into the parent
                     // by calling `Type::record` instead of `visitor.visit_set`
-                    if let (Type::Path(ty), Meta::List(list)) = (&field.ty, &serde.meta) {
-                        for token in list.tokens.clone() {
-                            if let TokenTree::Ident(ident) = token {
-                                if ident == "flatten" {
-                                    let ty_name = ty.path.require_ident()?;
-                                    output.push(quote_spanned!(
-                                        ident.span() => (#ty_name::record(visit))
-                                    ));
-                                    break;
-                                }
-                            }
-                        }
+                    if serde_field.flatten() {
+                        let ty_name = ty.path.require_ident()?;
+                        output.push(quote_spanned!(ident.span() => (#ty_name::record(visit))));
                     }
                 }
             }
@@ -193,6 +182,10 @@ fn handle_option(field: &Field, attr: &Attribute) -> syn::Result<proc_macro2::To
     } = attr.parse_args::<FieldAttributes>()?;
     let kebab_name = LitStr::new(&ident.to_string().replace('_', "-"), ident.span());
 
+    let serde_field = serde_field_metadata(field)?;
+    let attributed_aliases = serde_field.aliases();
+    let aliases = quote!(BTreeSet::from_iter([#(#attributed_aliases),*]));
+
     Ok(quote_spanned!(
         ident.span() => {
             visit.record_field(#kebab_name, crate::options_base::OptionField{
@@ -200,6 +193,7 @@ fn handle_option(field: &Field, attr: &Attribute) -> syn::Result<proc_macro2::To
                 default: &#default,
                 value_type: &#value_type,
                 example: &#example,
+                aliases: #aliases
             })
         }
     ))
@@ -248,3 +242,17 @@ fn _parse_key_value(input: ParseStream, name: &str) -> syn::Result<String> {
         _ => Err(syn::Error::new(value.span(), "Expected literal string")),
     }
 }
+
+fn serde_field_metadata(field: &Field) -> syn::Result<serde_derive_internals::attr::Field> {
+    let context = Ctxt::new();
+    let field = serde_derive_internals::attr::Field::from_ast(
+        &context,
+        0,
+        field,
+        None,
+        &serde_derive_internals::attr::Default::Default,
+    );
+    context.check()?;
+
+    Ok(field)
+}

crates/ruff_workspace/src/configuration.rs

@@ -4,7 +4,7 @@
 
 use std::borrow::Cow;
 use std::env::VarError;
-use std::num::NonZeroU16;
+use std::num::{NonZeroU16, NonZeroU8};
 use std::path::{Path, PathBuf};
 
 use anyhow::{anyhow, Result};
@@ -16,7 +16,7 @@ use shellexpand::LookupError;
 use strum::IntoEnumIterator;
 
 use ruff_cache::cache_dir;
-use ruff_formatter::{IndentStyle, LineWidth};
+use ruff_formatter::{IndentStyle, IndentWidth, LineWidth};
 use ruff_linter::line_width::{LineLength, TabSize};
 use ruff_linter::registry::RuleNamespace;
 use ruff_linter::registry::{Rule, RuleSet, INCOMPATIBLE_CODES};
@@ -155,7 +155,7 @@ impl Configuration {
 
         let format = self.format;
         let format_defaults = FormatterSettings::default();
-        // TODO(micha): Support changing the tab-width but disallow changing the number of spaces
+
         let formatter = FormatterSettings {
             exclude: FilePatternSet::try_from_iter(format.exclude.unwrap_or_default())?,
             preview: match format.preview.unwrap_or(global_preview) {
@@ -169,6 +169,11 @@ impl Configuration {
                 }),
             line_ending: format.line_ending.unwrap_or(format_defaults.line_ending),
             indent_style: format.indent_style.unwrap_or(format_defaults.indent_style),
+            indent_width: self
+                .tab_size
+                .map_or(format_defaults.indent_width, |tab_size| {
+                    IndentWidth::from(NonZeroU8::from(tab_size))
+                }),
             quote_style: format.quote_style.unwrap_or(format_defaults.quote_style),
             magic_trailing_comma: format
                 .magic_trailing_comma

crates/ruff_workspace/src/options.rs

@@ -363,7 +363,11 @@ pub struct Options {
     )]
     pub line_length: Option<LineLength>,
 
-    /// The tabulation size to calculate line length.
+    /// The number of spaces a tab is equal to when enforcing long-line violations (like `E501`)
+    /// or formatting code with the formatter.
+    ///
+    /// This option changes the number of spaces inserted by the formatter when
+    /// using soft-tabs (`indent-style = space`).
     #[option(
         default = "4",
         value_type = "int",

crates/ruff_workspace/src/options_base.rs

@@ -1,3 +1,4 @@
+use std::collections::BTreeSet;
 use std::fmt::{Debug, Display, Formatter};
 
 /// Visits [`OptionsMetadata`].
@@ -89,7 +90,8 @@ impl OptionSet {
     /// ### Test for the existence of a child option
     ///
     /// ```rust
-    /// # use ruff_workspace::options_base::{OptionField, OptionsMetadata, Visit};
+    /// # use std::collections::BTreeSet;
+    /// use ruff_workspace::options_base::{OptionField, OptionsMetadata, Visit};
     ///
     /// struct WithOptions;
     ///
@@ -100,6 +102,7 @@ impl OptionSet {
     ///             default: "false",
     ///             value_type: "bool",
     ///             example: "",
+    ///             aliases: BTreeSet::new()
     ///         });
     ///     }
     /// }
@@ -110,7 +113,8 @@ impl OptionSet {
     /// ### Test for the existence of a nested option
     ///
     /// ```rust
-    /// # use ruff_workspace::options_base::{OptionField, OptionsMetadata, Visit};
+    /// # use std::collections::BTreeSet;
+    /// use ruff_workspace::options_base::{OptionField, OptionsMetadata, Visit};
     ///
     /// struct Root;
     ///
@@ -121,6 +125,7 @@ impl OptionSet {
     ///             default: "false",
     ///             value_type: "bool",
     ///             example: "",
+    ///             aliases: BTreeSet::new()
     ///         });
     ///
     ///         visit.record_set("format", Nested::metadata());
@@ -136,6 +141,7 @@ impl OptionSet {
     ///             default: "false",
     ///             value_type: "bool",
     ///             example: "",
+    ///             aliases: BTreeSet::new()
     ///         });
     ///     }
     /// }
@@ -157,7 +163,8 @@ impl OptionSet {
     /// ### Find a child option
     ///
     /// ```rust
-    /// # use ruff_workspace::options_base::{OptionEntry, OptionField, OptionsMetadata, Visit};
+    /// # use std::collections::BTreeSet;
+    /// use ruff_workspace::options_base::{OptionEntry, OptionField, OptionsMetadata, Visit};
     ///
     /// struct WithOptions;
     ///
@@ -166,6 +173,7 @@ impl OptionSet {
     ///     default: "false",
     ///     value_type: "bool",
     ///     example: "",
+    ///     aliases: BTreeSet::new()
     ///  };
     ///
     /// impl OptionsMetadata for WithOptions {
@@ -180,13 +188,15 @@ impl OptionSet {
     /// ### Find a nested option
     ///
     /// ```rust
-    /// # use ruff_workspace::options_base::{OptionEntry, OptionField, OptionsMetadata, Visit};
+    /// # use std::collections::BTreeSet;
+    /// use ruff_workspace::options_base::{OptionEntry, OptionField, OptionsMetadata, Visit};
     ///
     /// static HARD_TABS: OptionField = OptionField {
     ///     doc: "Use hard tabs for indentation and spaces for alignment.",
     ///     default: "false",
     ///     value_type: "bool",
     ///     example: "",
+    ///     aliases: BTreeSet::new()
     /// };
     ///
     /// struct Root;
@@ -198,6 +208,7 @@ impl OptionSet {
     ///             default: "false",
     ///             value_type: "bool",
     ///             example: "",
+    ///             aliases: BTreeSet::new()
     ///         });
     ///
     ///         visit.record_set("format", Nested::metadata());
@@ -307,6 +318,7 @@ pub struct OptionField {
     pub doc: &'static str,
     pub default: &'static str,
     pub value_type: &'static str,
+    pub aliases: BTreeSet<&'static str>,
     pub example: &'static str,
 }
 

crates/ruff_workspace/src/settings.rs

@@ -1,6 +1,6 @@
 use path_absolutize::path_dedot;
 use ruff_cache::cache_dir;
-use ruff_formatter::{FormatOptions, IndentStyle, LineWidth};
+use ruff_formatter::{FormatOptions, IndentStyle, IndentWidth, LineWidth};
 use ruff_linter::settings::types::{FilePattern, FilePatternSet, SerializationFormat, UnsafeFixes};
 use ruff_linter::settings::LinterSettings;
 use ruff_macros::CacheKey;
@@ -117,6 +117,7 @@ pub struct FormatterSettings {
     pub line_width: LineWidth,
 
     pub indent_style: IndentStyle,
+    pub indent_width: IndentWidth,
 
     pub quote_style: QuoteStyle,
 
@@ -150,6 +151,7 @@ impl FormatterSettings {
 
         PyFormatOptions::from_source_type(source_type)
             .with_indent_style(self.indent_style)
+            .with_indent_width(self.indent_width)
             .with_quote_style(self.quote_style)
             .with_magic_trailing_comma(self.magic_trailing_comma)
             .with_preview(self.preview)
@@ -164,10 +166,11 @@ impl Default for FormatterSettings {
 
         Self {
             exclude: FilePatternSet::default(),
-            preview: ruff_python_formatter::PreviewMode::Disabled,
+            preview: PreviewMode::Disabled,
             line_width: default_options.line_width(),
             line_ending: LineEnding::Lf,
             indent_style: default_options.indent_style(),
+            indent_width: default_options.indent_width(),
             quote_style: default_options.quote_style(),
             magic_trailing_comma: default_options.magic_trailing_comma(),
         }

ruff.schema.json

@@ -605,7 +605,7 @@
       }
     },
     "tab-size": {
-      "description": "The tabulation size to calculate line length.",
+      "description": "The number of spaces a tab is equal to when enforcing long-line violations (like `E501`) or formatting code with the formatter.\n\nThis option changes the number of spaces inserted by the formatter when using soft-tabs (`indent-style = space`).",
       "anyOf": [
         {
           "$ref": "#/definitions/TabSize"