Ignore overlong pragma comments when enforcing linter line length

crates/ruff_linter/resources/test/fixtures/pycodestyle/E501_1.py

@@ -1,6 +1,8 @@
 # TODO: comments starting with one of the configured task-tags sometimes are longer than line-length so that you can easily find them with `git grep`
+# TODO(charlie): comments starting with one of the configured task-tags sometimes are longer than line-length so that you can easily find them with `git grep`
 # TODO comments starting with one of the configured task-tags sometimes are longer than line-length so that you can easily find them with `git grep`
 #     TODO    comments starting with one of the configured task-tags sometimes are longer than line-length so that you can easily find them with `git grep`
 # FIXME: comments starting with one of the configured task-tags sometimes are longer than line-length so that you can easily find them with `git grep`
 # FIXME comments starting with one of the configured task-tags sometimes are longer than line-length so that you can easily find them with `git grep`
 #     FIXME    comments starting with one of the configured task-tags sometimes are longer than line-length so that you can easily find them with `git grep`
+# FIXME(charlie): comments starting with one of the configured task-tags sometimes are longer than line-length so that you can easily find them with `git grep`

crates/ruff_linter/resources/test/fixtures/pycodestyle/E501_3.py

@@ -0,0 +1,11 @@
+# OK (88 characters)
+"shape:" + "shape:" + "shape:" + "shape:" + "shape:" + "shape:" + "shape:" + "shape:aaa"  # type: ignore
+
+# OK (88 characters)
+"shape:" + "shape:" + "shape:" + "shape:" + "shape:" + "shape:" + "shape:" + "shape:aaa"# type: ignore
+
+# OK (88 characters)
+"shape:" + "shape:" + "shape:" + "shape:" + "shape:" + "shape:" + "shape:" + "shape:aaa"    # type: ignore
+
+# Error (89 characters)
+"shape:" + "shape:" + "shape:" + "shape:" + "shape:" + "shape:" + "shape:" + "shape:aaaa"  # type: ignore

crates/ruff_linter/src/checkers/physical_lines.rs

@@ -41,7 +41,7 @@ pub(crate) fn check_physical_lines(
             .is_some()
         {
             if enforce_doc_line_too_long {
-                if let Some(diagnostic) = doc_line_too_long(&line, settings) {
+                if let Some(diagnostic) = doc_line_too_long(&line, indexer, settings) {
                     diagnostics.push(diagnostic);
                 }
             }
@@ -54,7 +54,7 @@ pub(crate) fn check_physical_lines(
         }
 
         if enforce_line_too_long {
-            if let Some(diagnostic) = line_too_long(&line, settings) {
+            if let Some(diagnostic) = line_too_long(&line, indexer, settings) {
                 diagnostics.push(diagnostic);
             }
         }

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

@@ -1,9 +1,11 @@
+use std::borrow::Cow;
 use unicode_width::UnicodeWidthStr;
 
 use ruff_python_ast::node::AnyNodeRef;
 use ruff_python_ast::parenthesize::parenthesized_range;
 use ruff_python_ast::{CmpOp, Expr};
-use ruff_python_trivia::CommentRanges;
+use ruff_python_index::Indexer;
+use ruff_python_trivia::{is_pragma_comment, CommentRanges};
 use ruff_source_file::{Line, Locator};
 use ruff_text_size::{Ranged, TextLen, TextRange};
 
@@ -68,6 +70,7 @@ pub(super) fn generate_comparison(
 pub(super) fn is_overlong(
     line: &Line,
     limit: LineLength,
+    indexer: &Indexer,
     ignore_overlong_task_comments: bool,
     task_tags: &[String],
     tab_size: TabSize,
@@ -80,27 +83,51 @@ pub(super) fn is_overlong(
         return None;
     }
 
-    let mut width = LineWidthBuilder::new(tab_size);
-    width = width.add_str(line.as_str());
+    // If the line ends in a pragma, remove it from the considered width.
+    let mut line = Cow::Borrowed(line);
+    if let [comment_range] = indexer.comment_ranges().comments_in_range(line.range()) {
+        // Convert from absolute to relative range.
+        let comment_range = comment_range - line.start();
+        let comment = &line.as_str()[comment_range];
+
+        // Ex) `# type: ignore`
+        if is_pragma_comment(comment) {
+            // Remove the pragma from the line.
+            let prefix = &line.as_str()[..usize::from(comment_range.start())].trim_end();
+            line = Cow::Owned(Line::new(prefix, line.start()));
+        }
+
+        // Ex) `# TODO(charlie): ...`
+        if ignore_overlong_task_comments {
+            let trimmed = comment.strip_prefix('#').unwrap_or(comment);
+            let trimmed = trimmed.trim_start();
+            if task_tags
+                .iter()
+                .any(|task_tag| trimmed.starts_with(task_tag))
+            {
+                // Remove the task tag from the line.
+                let prefix = &line.as_str()[..usize::from(comment_range.start())].trim_end();
+                line = Cow::Owned(Line::new(prefix, line.start()));
+            }
+        }
+    }
+
+    let width = {
+        let mut width = LineWidthBuilder::new(tab_size);
+        width = width.add_str(line.as_str());
+        width
+    };
+
     if width <= limit {
         return None;
     }
 
     let mut chunks = line.split_whitespace();
-    let (Some(first_chunk), Some(second_chunk)) = (chunks.next(), chunks.next()) else {
+    let (Some(_), Some(second_chunk)) = (chunks.next(), chunks.next()) else {
         // Single word / no printable chars - no way to make the line shorter
         return None;
     };
 
-    if first_chunk == "#" {
-        if ignore_overlong_task_comments {
-            let second = second_chunk.trim_end_matches(':');
-            if task_tags.iter().any(|task_tag| task_tag == second) {
-                return None;
-            }
-        }
-    }
-
     // Do not enforce the line length for lines that end with a URL, as long as the URL
     // begins before the limit.
     let last_chunk = chunks.last().unwrap_or(second_chunk);
@@ -121,6 +148,7 @@ pub(super) fn is_overlong(
             break;
         }
     }
+
     Some(Overlong {
         range: TextRange::new(start_offset, line.end()),
         width: width.get(),

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

@@ -29,6 +29,7 @@ mod tests {
     #[test_case(Rule::InvalidEscapeSequence, Path::new("W605_0.py"))]
     #[test_case(Rule::InvalidEscapeSequence, Path::new("W605_1.py"))]
     #[test_case(Rule::LineTooLong, Path::new("E501.py"))]
+    #[test_case(Rule::LineTooLong, Path::new("E501_3.py"))]
     #[test_case(Rule::MixedSpacesAndTabs, Path::new("E101.py"))]
     #[test_case(Rule::ModuleImportNotAtTopOfFile, Path::new("E40.py"))]
     #[test_case(Rule::ModuleImportNotAtTopOfFile, Path::new("E402.py"))]

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

@@ -1,5 +1,6 @@
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
+use ruff_python_index::Indexer;
 use ruff_source_file::Line;
 
 use crate::rules::pycodestyle::helpers::is_overlong;
@@ -19,10 +20,17 @@ use crate::settings::LinterSettings;
 /// of either a standalone comment or a standalone string, like a docstring.
 ///
 /// In the interest of pragmatism, this rule makes a few exceptions when
-/// determining whether a line is overlong. Namely, it ignores lines that
-/// consist of a single "word" (i.e., without any whitespace between its
-/// characters), and lines that end with a URL (as long as the URL starts
-/// before the line-length threshold).
+/// determining whether a line is overlong. Namely, it:
+///
+/// 1. Ignores lines that consist of a single "word" (i.e., without any
+///    whitespace between its characters).
+/// 2. Ignores lines that end with a URL, as long as the URL starts before
+///    the line-length threshold.
+/// 3. Ignores line that end with a pragma comment (e.g., `# type: ignore`
+///    or `# noqa`), as long as the pragma comment starts before the
+///    line-length threshold. That is, a line will not be flagged as
+///    overlong if a pragma comment _causes_ it to exceed the line length.
+///    (This behavior aligns with that of the Ruff formatter.)
 ///
 /// If [`pycodestyle.ignore-overlong-task-comments`] is `true`, this rule will
 /// also ignore comments that start with any of the specified [`task-tags`]
@@ -50,7 +58,7 @@ use crate::settings::LinterSettings;
 ///
 /// [PEP 8]: https://peps.python.org/pep-0008/#maximum-line-length
 #[violation]
-pub struct DocLineTooLong(pub usize, pub usize);
+pub struct DocLineTooLong(usize, usize);
 
 impl Violation for DocLineTooLong {
     #[derive_message_formats]
@@ -61,14 +69,19 @@ impl Violation for DocLineTooLong {
 }
 
 /// W505
-pub(crate) fn doc_line_too_long(line: &Line, settings: &LinterSettings) -> Option<Diagnostic> {
+pub(crate) fn doc_line_too_long(
+    line: &Line,
+    indexer: &Indexer,
+    settings: &LinterSettings,
+) -> Option<Diagnostic> {
     let Some(limit) = settings.pycodestyle.max_doc_length else {
         return None;
     };
 
     is_overlong(
         line,
         limit,
+        indexer,
         settings.pycodestyle.ignore_overlong_task_comments,
         &settings.task_tags,
         settings.tab_size,

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

@@ -1,5 +1,6 @@
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
+use ruff_python_index::Indexer;
 use ruff_source_file::Line;
 
 use crate::rules::pycodestyle::helpers::is_overlong;
@@ -15,10 +16,17 @@ use crate::settings::LinterSettings;
 /// configurable via the [`line-length`] setting.
 ///
 /// In the interest of pragmatism, this rule makes a few exceptions when
-/// determining whether a line is overlong. Namely, it ignores lines that
-/// consist of a single "word" (i.e., without any whitespace between its
-/// characters), and lines that end with a URL (as long as the URL starts
-/// before the line-length threshold).
+/// determining whether a line is overlong. Namely, it:
+///
+/// 1. Ignores lines that consist of a single "word" (i.e., without any
+///    whitespace between its characters).
+/// 2. Ignores lines that end with a URL, as long as the URL starts before
+///    the line-length threshold.
+/// 3. Ignores line that end with a pragma comment (e.g., `# type: ignore`
+///    or `# noqa`), as long as the pragma comment starts before the
+///    line-length threshold. That is, a line will not be flagged as
+///    overlong if a pragma comment _causes_ it to exceed the line length.
+///    (This behavior aligns with that of the Ruff formatter.)
 ///
 /// If [`pycodestyle.ignore-overlong-task-comments`] is `true`, this rule will
 /// also ignore comments that start with any of the specified [`task-tags`]
@@ -44,7 +52,7 @@ use crate::settings::LinterSettings;
 ///
 /// [PEP 8]: https://peps.python.org/pep-0008/#maximum-line-length
 #[violation]
-pub struct LineTooLong(pub usize, pub usize);
+pub struct LineTooLong(usize, usize);
 
 impl Violation for LineTooLong {
     #[derive_message_formats]
@@ -55,12 +63,17 @@ impl Violation for LineTooLong {
 }
 
 /// E501
-pub(crate) fn line_too_long(line: &Line, settings: &LinterSettings) -> Option<Diagnostic> {
+pub(crate) fn line_too_long(
+    line: &Line,
+    indexer: &Indexer,
+    settings: &LinterSettings,
+) -> Option<Diagnostic> {
     let limit = settings.line_length;
 
     is_overlong(
         line,
         limit,
+        indexer,
         settings.pycodestyle.ignore_overlong_task_comments,
         &settings.task_tags,
         settings.tab_size,

crates/ruff_linter/src/rules/pycodestyle/snapshots/ruff_linter__rules__pycodestyle__tests__E501_E501_3.py.snap

@@ -0,0 +1,11 @@
+---
+source: crates/ruff_linter/src/rules/pycodestyle/mod.rs
+---
+E501_3.py:11:89: E501 Line too long (89 > 88 characters)
+   |
+10 | # Error (89 characters)
+11 | "shape:" + "shape:" + "shape:" + "shape:" + "shape:" + "shape:" + "shape:" + "shape:aaaa"  # type: ignore
+   |                                                                                         ^ E501
+   |
+
+