Rename tab-size to indent-width (#8082)

## Summary

This PR renames the `tab-size` configuration option to `indent-width` to
express that the formatter uses the option to determine the indentation
width AND as tab width.

I first preferred naming the option `tab-width` but then decided to go
with `indent-width` because:

* It aligns with the `indent-style` option
* It would allow us to write a lint rule that asserts that each
indentation uses `indent-width` spaces.

 Closes #7643

## Test Plan

Added integration test

crates/ruff_cli/tests/format.rs

@@ -50,7 +50,7 @@ fn format_options() -> Result<()> {
     fs::write(
         &ruff_toml,
         r#"
-tab-size = 8
+indent-width = 8
 line-length = 84
 
 [format]
@@ -278,6 +278,41 @@ if condition:
     Ok(())
 }
 
+#[test]
+fn deprecated_options() -> Result<()> {
+    let tempdir = TempDir::new()?;
+    let ruff_toml = tempdir.path().join("ruff.toml");
+    fs::write(
+        &ruff_toml,
+        r#"
+tab-size = 2
+"#,
+    )?;
+
+    insta::with_settings!({filters => vec![
+        (&*regex::escape(ruff_toml.to_str().unwrap()), "[RUFF-TOML-PATH]"),
+    ]}, {
+        assert_cmd_snapshot!(Command::new(get_cargo_bin(BIN_NAME))
+            .args(["format", "--config"])
+            .arg(&ruff_toml)
+            .arg("-")
+            .pass_stdin(r#"
+if True:
+    pass
+    "#), @r###"
+        success: true
+        exit_code: 0
+        ----- stdout -----
+        if True:
+          pass
+
+        ----- stderr -----
+        warning: The `tab-size` option has been renamed to `indent-width` to emphasize that it configures the indentation used by the formatter as well as the tab width. Please update your configuration to use `indent-width = <value>` instead.
+        "###);
+    });
+    Ok(())
+}
+
 /// Since 0.1.0 the legacy format option is no longer supported
 #[test]
 fn legacy_format_option() -> Result<()> {

crates/ruff_linter/src/fix/edits.rs

@@ -14,7 +14,7 @@ use ruff_source_file::{Locator, NewlineWithTrailingNewline, UniversalNewlines};
 use ruff_text_size::{Ranged, TextLen, TextRange, TextSize};
 
 use crate::fix::codemods;
-use crate::line_width::{LineLength, LineWidthBuilder, TabSize};
+use crate::line_width::{IndentWidth, LineLength, LineWidthBuilder};
 
 /// Return the `Fix` to use when deleting a `Stmt`.
 ///
@@ -293,7 +293,7 @@ pub(crate) fn fits(
     node: AnyNodeRef,
     locator: &Locator,
     line_length: LineLength,
-    tab_size: TabSize,
+    tab_size: IndentWidth,
 ) -> bool {
     all_lines_fit(fix, node, locator, line_length.value() as usize, tab_size)
 }
@@ -305,7 +305,7 @@ pub(crate) fn fits_or_shrinks(
     node: AnyNodeRef,
     locator: &Locator,
     line_length: LineLength,
-    tab_size: TabSize,
+    tab_size: IndentWidth,
 ) -> bool {
     // Use the larger of the line length limit, or the longest line in the existing AST node.
     let line_length = std::iter::once(line_length.value() as usize)
@@ -327,7 +327,7 @@ fn all_lines_fit(
     node: AnyNodeRef,
     locator: &Locator,
     line_length: usize,
-    tab_size: TabSize,
+    tab_size: IndentWidth,
 ) -> bool {
     let prefix = locator.slice(TextRange::new(
         locator.line_start(node.start()),

crates/ruff_linter/src/line_width.rs

@@ -129,12 +129,12 @@ pub struct LineWidthBuilder {
     /// This is used to calculate the width of tabs.
     column: usize,
     /// The tab size to use when calculating the width of tabs.
-    tab_size: TabSize,
+    tab_size: IndentWidth,
 }
 
 impl Default for LineWidthBuilder {
     fn default() -> Self {
-        Self::new(TabSize::default())
+        Self::new(IndentWidth::default())
     }
 }
 
@@ -164,7 +164,7 @@ impl LineWidthBuilder {
     }
 
     /// Creates a new `LineWidth` with the given tab size.
-    pub fn new(tab_size: TabSize) -> Self {
+    pub fn new(tab_size: IndentWidth) -> Self {
         LineWidthBuilder {
             width: 0,
             column: 0,
@@ -234,28 +234,28 @@ impl PartialOrd<LineLength> for LineWidthBuilder {
 /// The size of a tab.
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Serialize, Deserialize, CacheKey)]
 #[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
-pub struct TabSize(NonZeroU8);
+pub struct IndentWidth(NonZeroU8);
 
-impl TabSize {
+impl IndentWidth {
     pub(crate) fn as_usize(self) -> usize {
         self.0.get() as usize
     }
 }
 
-impl Default for TabSize {
+impl Default for IndentWidth {
     fn default() -> Self {
         Self(NonZeroU8::new(4).unwrap())
     }
 }
 
-impl From<NonZeroU8> for TabSize {
+impl From<NonZeroU8> for IndentWidth {
     fn from(tab_size: NonZeroU8) -> Self {
         Self(tab_size)
     }
 }
 
-impl From<TabSize> for NonZeroU8 {
-    fn from(value: TabSize) -> Self {
+impl From<IndentWidth> for NonZeroU8 {
+    fn from(value: IndentWidth) -> Self {
         value.0
     }
 }

crates/ruff_linter/src/message/text.rs

@@ -12,7 +12,7 @@ use ruff_source_file::{OneIndexed, SourceLocation};
 use ruff_text_size::{Ranged, TextRange, TextSize};
 
 use crate::fs::relativize_path;
-use crate::line_width::{LineWidthBuilder, TabSize};
+use crate::line_width::{IndentWidth, LineWidthBuilder};
 use crate::message::diff::Diff;
 use crate::message::{Emitter, EmitterContext, Message};
 use crate::registry::AsRule;
@@ -300,7 +300,7 @@ fn replace_whitespace(source: &str, annotation_range: TextRange) -> SourceCode {
     let mut result = String::new();
     let mut last_end = 0;
     let mut range = annotation_range;
-    let mut line_width = LineWidthBuilder::new(TabSize::default());
+    let mut line_width = LineWidthBuilder::new(IndentWidth::default());
 
     for (index, c) in source.char_indices() {
         let old_width = line_width.get();

crates/ruff_linter/src/rules/pycodestyle/overlong.rs

@@ -7,7 +7,7 @@ use ruff_python_trivia::is_pragma_comment;
 use ruff_source_file::Line;
 use ruff_text_size::{TextLen, TextRange};
 
-use crate::line_width::{LineLength, LineWidthBuilder, TabSize};
+use crate::line_width::{IndentWidth, LineLength, LineWidthBuilder};
 
 #[derive(Debug)]
 pub(super) struct Overlong {
@@ -23,7 +23,7 @@ impl Overlong {
         indexer: &Indexer,
         limit: LineLength,
         task_tags: &[String],
-        tab_size: TabSize,
+        tab_size: IndentWidth,
     ) -> Option<Self> {
         // The maximum width of the line is the number of bytes multiplied by the tab size (the
         // worst-case scenario is that the line is all tabs). If the maximum width is less than the
@@ -158,7 +158,7 @@ impl<'a> Deref for StrippedLine<'a> {
 }
 
 /// Returns the width of a given string, accounting for the tab size.
-fn measure(s: &str, tab_size: TabSize) -> LineWidthBuilder {
+fn measure(s: &str, tab_size: IndentWidth) -> LineWidthBuilder {
     let mut width = LineWidthBuilder::new(tab_size);
     width = width.add_str(s);
     width

crates/ruff_linter/src/settings/mod.rs

@@ -26,7 +26,7 @@ use crate::rules::{
 use crate::settings::types::{FilePatternSet, PerFileIgnore, PythonVersion};
 use crate::{codes, RuleSelector};
 
-use super::line_width::TabSize;
+use super::line_width::IndentWidth;
 
 use self::rule_table::RuleTable;
 use self::types::PreviewMode;
@@ -59,7 +59,7 @@ pub struct LinterSettings {
     pub logger_objects: Vec<String>,
     pub namespace_packages: Vec<PathBuf>,
     pub src: Vec<PathBuf>,
-    pub tab_size: TabSize,
+    pub tab_size: IndentWidth,
     pub task_tags: Vec<String>,
     pub typing_modules: Vec<String>,
 
@@ -155,7 +155,7 @@ impl LinterSettings {
 
             src: vec![path_dedot::CWD.clone()],
             // Needs duplicating
-            tab_size: TabSize::default(),
+            tab_size: IndentWidth::default(),
 
             task_tags: TASK_TAGS.iter().map(ToString::to_string).collect(),
             typing_modules: vec![],

crates/ruff_wasm/src/lib.rs

@@ -6,7 +6,7 @@ use wasm_bindgen::prelude::*;
 
 use ruff_formatter::{FormatResult, Formatted, IndentStyle};
 use ruff_linter::directives;
-use ruff_linter::line_width::{LineLength, TabSize};
+use ruff_linter::line_width::{IndentWidth, LineLength};
 use ruff_linter::linter::{check_path, LinterResult};
 use ruff_linter::registry::AsRule;
 use ruff_linter::settings::types::PythonVersion;
@@ -126,7 +126,7 @@ impl Workspace {
 
             line_length: Some(LineLength::default()),
 
-            tab_size: Some(TabSize::default()),
+            indent_width: Some(IndentWidth::default()),
             target_version: Some(PythonVersion::default()),
 
             lint: Some(LintOptions {

crates/ruff_workspace/src/configuration.rs

@@ -16,8 +16,8 @@ use shellexpand::LookupError;
 use strum::IntoEnumIterator;
 
 use ruff_cache::cache_dir;
-use ruff_formatter::{IndentStyle, IndentWidth, LineWidth};
-use ruff_linter::line_width::{LineLength, TabSize};
+use ruff_formatter::IndentStyle;
+use ruff_linter::line_width::{IndentWidth, LineLength};
 use ruff_linter::registry::RuleNamespace;
 use ruff_linter::registry::{Rule, RuleSet, INCOMPATIBLE_CODES};
 use ruff_linter::rule_selector::{PreviewOptions, Specificity};
@@ -133,7 +133,7 @@ pub struct Configuration {
 
     // Global formatting options
     pub line_length: Option<LineLength>,
-    pub tab_size: Option<TabSize>,
+    pub indent_width: Option<IndentWidth>,
 
     pub lint: LintConfiguration,
     pub format: FormatConfiguration,
@@ -166,14 +166,14 @@ impl Configuration {
             line_width: self
                 .line_length
                 .map_or(format_defaults.line_width, |length| {
-                    LineWidth::from(NonZeroU16::from(length))
+                    ruff_formatter::LineWidth::from(NonZeroU16::from(length))
                 }),
             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
+                .indent_width
                 .map_or(format_defaults.indent_width, |tab_size| {
-                    IndentWidth::from(NonZeroU8::from(tab_size))
+                    ruff_formatter::IndentWidth::from(NonZeroU8::from(tab_size))
                 }),
             quote_style: format.quote_style.unwrap_or(format_defaults.quote_style),
             magic_trailing_comma: format
@@ -228,7 +228,7 @@ impl Configuration {
                     .unwrap_or_else(|| DUMMY_VARIABLE_RGX.clone()),
                 external: FxHashSet::from_iter(lint.external.unwrap_or_default()),
                 ignore_init_module_imports: lint.ignore_init_module_imports.unwrap_or_default(),
-                tab_size: self.tab_size.unwrap_or_default(),
+                tab_size: self.indent_width.unwrap_or_default(),
                 namespace_packages: self.namespace_packages.unwrap_or_default(),
                 per_file_ignores: resolve_per_file_ignores(
                     lint.per_file_ignores
@@ -389,6 +389,15 @@ impl Configuration {
             }
         };
 
+        #[allow(deprecated)]
+        let indent_width = {
+            if options.tab_size.is_some() {
+                warn_user_once!("The `tab-size` option has been renamed to `indent-width` to emphasize that it configures the indentation used by the formatter as well as the tab width. Please update your configuration to use `indent-width = <value>` instead.");
+            }
+
+            options.indent_width.or(options.tab_size)
+        };
+
         Ok(Self {
             builtins: options.builtins,
             cache_dir: options
@@ -456,7 +465,7 @@ impl Configuration {
             output_format: options.output_format,
             force_exclude: options.force_exclude,
             line_length: options.line_length,
-            tab_size: options.tab_size,
+            indent_width,
             namespace_packages: options
                 .namespace_packages
                 .map(|namespace_package| resolve_src(&namespace_package, project_root))
@@ -504,7 +513,7 @@ impl Configuration {
             output_format: self.output_format.or(config.output_format),
             force_exclude: self.force_exclude.or(config.force_exclude),
             line_length: self.line_length.or(config.line_length),
-            tab_size: self.tab_size.or(config.tab_size),
+            indent_width: self.indent_width.or(config.indent_width),
             namespace_packages: self.namespace_packages.or(config.namespace_packages),
             required_version: self.required_version.or(config.required_version),
             respect_gitignore: self.respect_gitignore.or(config.respect_gitignore),