Add fix for comment-related whitespace rules (#9075)

Closes #9067.

Closes #9068.

Closes #8119.

crates/ruff_linter/resources/test/fixtures/pycodestyle/E26.py

@@ -72,3 +72,15 @@ def oof():
 # EF  Means test is giving error and Failing
 #!   Means test is segfaulting
 # 8   Means test runs forever
+
+#: Colon prefix is okay
+
+###This is a variable ###
+
+# We should strip the space, but preserve the hashes.
+#: E266:1:3
+##  Foo
+
+a = 1  ## Foo
+
+a = 1  #:Foo

crates/ruff_linter/src/rules/pycodestyle/rules/logical_lines/whitespace_before_comment.rs

@@ -1,4 +1,4 @@
-use ruff_diagnostics::{AlwaysFixableViolation, Diagnostic, Edit, Fix, Violation};
+use ruff_diagnostics::{AlwaysFixableViolation, Diagnostic, Edit, Fix};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_parser::TokenKind;
 use ruff_python_trivia::PythonWhitespace;
@@ -66,11 +66,15 @@ impl AlwaysFixableViolation for TooFewSpacesBeforeInlineComment {
 #[violation]
 pub struct NoSpaceAfterInlineComment;
 
-impl Violation for NoSpaceAfterInlineComment {
+impl AlwaysFixableViolation for NoSpaceAfterInlineComment {
     #[derive_message_formats]
     fn message(&self) -> String {
         format!("Inline comment should start with `# `")
     }
+
+    fn fix_title(&self) -> String {
+        format!("Format space")
+    }
 }
 
 /// ## What it does
@@ -98,11 +102,15 @@ impl Violation for NoSpaceAfterInlineComment {
 #[violation]
 pub struct NoSpaceAfterBlockComment;
 
-impl Violation for NoSpaceAfterBlockComment {
+impl AlwaysFixableViolation for NoSpaceAfterBlockComment {
     #[derive_message_formats]
     fn message(&self) -> String {
         format!("Block comment should start with `# `")
     }
+
+    fn fix_title(&self) -> String {
+        format!("Format space")
+    }
 }
 
 /// ## What it does
@@ -130,11 +138,15 @@ impl Violation for NoSpaceAfterBlockComment {
 #[violation]
 pub struct MultipleLeadingHashesForBlockComment;
 
-impl Violation for MultipleLeadingHashesForBlockComment {
+impl AlwaysFixableViolation for MultipleLeadingHashesForBlockComment {
     #[derive_message_formats]
     fn message(&self) -> String {
         format!("Too many leading `#` before block comment")
     }
+
+    fn fix_title(&self) -> String {
+        format!("Remove leading `#`")
+    }
 }
 
 /// E261, E262, E265, E266
@@ -184,14 +196,30 @@ pub(crate) fn whitespace_before_comment(
 
             if is_inline_comment {
                 if bad_prefix.is_some() || comment.chars().next().is_some_and(char::is_whitespace) {
-                    context.push(NoSpaceAfterInlineComment, range);
+                    let mut diagnostic = Diagnostic::new(NoSpaceAfterInlineComment, range);
+                    diagnostic.set_fix(Fix::safe_edit(Edit::range_replacement(
+                        format_leading_space(token_text),
+                        range,
+                    )));
+                    context.push_diagnostic(diagnostic);
                 }
             } else if let Some(bad_prefix) = bad_prefix {
                 if bad_prefix != '!' || !line.is_start_of_file() {
                     if bad_prefix != '#' {
-                        context.push(NoSpaceAfterBlockComment, range);
+                        let mut diagnostic = Diagnostic::new(NoSpaceAfterBlockComment, range);
+                        diagnostic.set_fix(Fix::safe_edit(Edit::range_replacement(
+                            format_leading_space(token_text),
+                            range,
+                        )));
+                        context.push_diagnostic(diagnostic);
                     } else if !comment.is_empty() {
-                        context.push(MultipleLeadingHashesForBlockComment, range);
+                        let mut diagnostic =
+                            Diagnostic::new(MultipleLeadingHashesForBlockComment, range);
+                        diagnostic.set_fix(Fix::safe_edit(Edit::range_replacement(
+                            format_leading_hashes(token_text),
+                            range,
+                        )));
+                        context.push_diagnostic(diagnostic);
                     }
                 }
             }
@@ -200,3 +228,17 @@ pub(crate) fn whitespace_before_comment(
         }
     }
 }
+
+/// Format a comment to have a single space after the `#`.
+fn format_leading_space(comment: &str) -> String {
+    if let Some(rest) = comment.strip_prefix("#:") {
+        format!("#: {}", rest.trim_start())
+    } else {
+        format!("# {}", comment.trim_start_matches('#').trim_start())
+    }
+}
+
+/// Format a comment to strip multiple leading `#` characters.
+fn format_leading_hashes(comment: &str) -> String {
+    format!("# {}", comment.trim_start_matches('#').trim_start())
+}

crates/ruff_linter/src/rules/pycodestyle/snapshots/ruff_linter__rules__pycodestyle__tests__E262_E26.py.snap

@@ -1,7 +1,7 @@
 ---
 source: crates/ruff_linter/src/rules/pycodestyle/mod.rs
 ---
-E26.py:4:12: E262 Inline comment should start with `# `
+E26.py:4:12: E262 [*] Inline comment should start with `# `
   |
 2 | pass # an inline comment
 3 | #: E262:1:12
@@ -10,8 +10,19 @@ E26.py:4:12: E262 Inline comment should start with `# `
 5 | #: E262:1:12
 6 | x = x + 1  #  Increment x
   |
+  = help: Format space
 
-E26.py:6:12: E262 Inline comment should start with `# `
+ℹ Safe fix
+1 1 | #: E261:1:5
+2 2 | pass # an inline comment
+3 3 | #: E262:1:12
+4   |-x = x + 1  #Increment x
+  4 |+x = x + 1  # Increment x
+5 5 | #: E262:1:12
+6 6 | x = x + 1  #  Increment x
+7 7 | #: E262:1:12
+
+E26.py:6:12: E262 [*] Inline comment should start with `# `
   |
 4 | x = x + 1  #Increment x
 5 | #: E262:1:12
@@ -20,8 +31,19 @@ E26.py:6:12: E262 Inline comment should start with `# `
 7 | #: E262:1:12
 8 | x = y + 1  #:  Increment x
   |
+  = help: Format space
+
+ℹ Safe fix
+3 3 | #: E262:1:12
+4 4 | x = x + 1  #Increment x
+5 5 | #: E262:1:12
+6   |-x = x + 1  #  Increment x
+  6 |+x = x + 1  # Increment x
+7 7 | #: E262:1:12
+8 8 | x = y + 1  #:  Increment x
+9 9 | #: E265:1:1
 
-E26.py:8:12: E262 Inline comment should start with `# `
+E26.py:8:12: E262 [*] Inline comment should start with `# `
    |
  6 | x = x + 1  #  Increment x
  7 | #: E262:1:12
@@ -30,8 +52,19 @@ E26.py:8:12: E262 Inline comment should start with `# `
  9 | #: E265:1:1
 10 | #Block comment
    |
+   = help: Format space
 
-E26.py:63:9: E262 Inline comment should start with `# `
+ℹ Safe fix
+5 5 | #: E262:1:12
+6 6 | x = x + 1  #  Increment x
+7 7 | #: E262:1:12
+8   |-x = y + 1  #:  Increment x
+  8 |+x = y + 1  #: Increment x
+9 9 | #: E265:1:1
+10 10 | #Block comment
+11 11 | a = 1
+
+E26.py:63:9: E262 [*] Inline comment should start with `# `
    |
 61 | # -*- coding: utf8 -*-
 62 | #  (One space one NBSP) Ok for block comment
@@ -40,8 +73,19 @@ E26.py:63:9: E262 Inline comment should start with `# `
 64 | #: E262:2:9
 65 | #  (Two spaces) Ok for block comment
    |
+   = help: Format space
+
+ℹ Safe fix
+60 60 | #: E262:3:9
+61 61 | # -*- coding: utf8 -*-
+62 62 | #  (One space one NBSP) Ok for block comment
+63    |-a = 42  #  (One space one NBSP)
+   63 |+a = 42  # (One space one NBSP)
+64 64 | #: E262:2:9
+65 65 | #  (Two spaces) Ok for block comment
+66 66 | a = 42  #  (Two spaces)
 
-E26.py:66:9: E262 Inline comment should start with `# `
+E26.py:66:9: E262 [*] Inline comment should start with `# `
    |
 64 | #: E262:2:9
 65 | #  (Two spaces) Ok for block comment
@@ -50,5 +94,52 @@ E26.py:66:9: E262 Inline comment should start with `# `
 67 | 
 68 | #: E265:5:1
    |
+   = help: Format space
+
+ℹ Safe fix
+63 63 | a = 42  #  (One space one NBSP)
+64 64 | #: E262:2:9
+65 65 | #  (Two spaces) Ok for block comment
+66    |-a = 42  #  (Two spaces)
+   66 |+a = 42  # (Two spaces)
+67 67 | 
+68 68 | #: E265:5:1
+69 69 | ### Means test is not done yet
+
+E26.py:84:8: E262 [*] Inline comment should start with `# `
+   |
+82 | ##  Foo
+83 | 
+84 | a = 1  ## Foo
+   |        ^^^^^^ E262
+85 | 
+86 | a = 1  #:Foo
+   |
+   = help: Format space
+
+ℹ Safe fix
+81 81 | #: E266:1:3
+82 82 | ##  Foo
+83 83 | 
+84    |-a = 1  ## Foo
+   84 |+a = 1  # Foo
+85 85 | 
+86 86 | a = 1  #:Foo
+
+E26.py:86:8: E262 [*] Inline comment should start with `# `
+   |
+84 | a = 1  ## Foo
+85 | 
+86 | a = 1  #:Foo
+   |        ^^^^^ E262
+   |
+   = help: Format space
+
+ℹ Safe fix
+83 83 | 
+84 84 | a = 1  ## Foo
+85 85 | 
+86    |-a = 1  #:Foo
+   86 |+a = 1  #: Foo