Don't attach comments with mismatched indents (#12604)

## Summary

Given:

```python
def test_update():
    pass
    # comment
def test_clientmodel():
    pass
```

We don't want `# comment` to be attached to `def test_clientmodel()`.

Closes https://github.com/astral-sh/ruff/issues/12589.

crates/ruff_linter/resources/test/fixtures/pycodestyle/E30.py

@@ -935,3 +935,30 @@ def arrow_strip_whitespace(obj: Array, /, *cols: str) -> Array: ...  # type: ign
 def arrow_strip_whitespace(obj, /, *cols):
     ...
 # end
+
+
+# E302
+def test_update():
+    pass
+    # comment
+def test_clientmodel():
+    pass
+# end
+
+
+# E302
+def test_update():
+    pass
+        # comment
+def test_clientmodel():
+    pass
+# end
+
+
+# E302
+def test_update():
+    pass
+# comment
+def test_clientmodel():
+    pass
+# end

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

@@ -352,13 +352,13 @@ struct LogicalLineInfo {
     kind: LogicalLineKind,
     first_token_range: TextRange,
 
-    // The kind of the last non-trivia token before the newline ending the logical line.
+    /// The kind of the last non-trivia token before the newline ending the logical line.
     last_token: TokenKind,
 
-    // The end of the logical line including the newline.
+    /// The end of the logical line including the newline.
     logical_line_end: TextSize,
 
-    // `true` if this is not a blank but only consists of a comment.
+    /// `true` if this is not a blank but only consists of a comment.
     is_comment_only: bool,
 
     /// If running on a notebook, whether the line is the first logical line (or a comment preceding it) of its cell.
@@ -721,6 +721,7 @@ impl<'a> BlankLinesChecker<'a> {
     /// E301, E302, E303, E304, E305, E306
     pub(crate) fn check_lines(&self, tokens: &Tokens, diagnostics: &mut Vec<Diagnostic>) {
         let mut prev_indent_length: Option<usize> = None;
+        let mut prev_logical_line: Option<LogicalLineInfo> = None;
         let mut state = BlankLinesState::default();
         let line_preprocessor =
             LinePreprocessor::new(tokens, self.locator, self.indent_width, self.cell_offsets);
@@ -739,6 +740,23 @@ impl<'a> BlankLinesChecker<'a> {
                 }
             }
 
+            // Reset the previous line end after an indent or dedent:
+            // ```python
+            // if True:
+            //      import test
+            //      # comment
+            // a = 10
+            // ```
+            // The `# comment` should be attached to the `import` statement, rather than the
+            // assignment.
+            if let Some(prev_logical_line) = prev_logical_line {
+                if prev_logical_line.is_comment_only {
+                    if prev_logical_line.indent_length != logical_line.indent_length {
+                        state.last_non_comment_line_end = prev_logical_line.logical_line_end;
+                    }
+                }
+            }
+
             state.class_status.update(&logical_line);
             state.fn_status.update(&logical_line);
 
@@ -793,6 +811,8 @@ impl<'a> BlankLinesChecker<'a> {
             if !logical_line.is_comment_only {
                 prev_indent_length = Some(logical_line.indent_length);
             }
+
+            prev_logical_line = Some(logical_line);
         }
     }
 
@@ -882,6 +902,8 @@ impl<'a> BlankLinesChecker<'a> {
                 line.first_token_range,
             );
 
+            // Check if the preceding comment
+
             if let Some(blank_lines_range) = line.blank_lines.range() {
                 diagnostic.set_fix(Fix::safe_edit(Edit::range_replacement(
                     self.stylist
@@ -891,9 +913,10 @@ impl<'a> BlankLinesChecker<'a> {
                 )));
             } else {
                 diagnostic.set_fix(Fix::safe_edit(Edit::insertion(
-                    self.stylist
-                        .line_ending()
-                        .repeat(expected_blank_lines_before_definition as usize),
+                    self.stylist.line_ending().repeat(
+                        (expected_blank_lines_before_definition
+                            - line.preceding_blank_lines.count()) as usize,
+                    ),
                     self.locator.line_start(state.last_non_comment_line_end),
                 )));
             }

crates/ruff_linter/src/rules/pycodestyle/snapshots/ruff_linter__rules__pycodestyle__tests__E302_E30.py.snap

@@ -179,10 +179,9 @@ E30.py:602:1: E302 [*] Expected 2 blank lines, found 1
 599 599 |     pass
 600 600 | 
     601 |+
-    602 |+
-601 603 | # comment
-602 604 | @decorator
-603 605 | def g():
+601 602 | # comment
+602 603 | @decorator
+603 604 | def g():
 
 E30.py:624:1: E302 [*] Expected 2 blank lines, found 0
     |
@@ -223,3 +222,66 @@ E30.py:634:1: E302 [*] Expected 2 blank lines, found 1
 634 635 | def fn(a: int | str) -> int | str:
 635 636 |     ...
 636 637 | # end
+
+E30.py:944:1: E302 [*] Expected 2 blank lines, found 0
+    |
+942 |     pass
+943 |     # comment
+944 | def test_clientmodel():
+    | ^^^ E302
+945 |     pass
+946 | # end
+    |
+    = help: Add missing blank line(s)
+
+ℹ Safe fix
+941 941 | def test_update():
+942 942 |     pass
+943 943 |     # comment
+    944 |+
+    945 |+
+944 946 | def test_clientmodel():
+945 947 |     pass
+946 948 | # end
+
+E30.py:953:1: E302 [*] Expected 2 blank lines, found 0
+    |
+951 |     pass
+952 |         # comment
+953 | def test_clientmodel():
+    | ^^^ E302
+954 |     pass
+955 | # end
+    |
+    = help: Add missing blank line(s)
+
+ℹ Safe fix
+950 950 | def test_update():
+951 951 |     pass
+952 952 |         # comment
+    953 |+
+    954 |+
+953 955 | def test_clientmodel():
+954 956 |     pass
+955 957 | # end
+
+E30.py:962:1: E302 [*] Expected 2 blank lines, found 0
+    |
+960 |     pass
+961 | # comment
+962 | def test_clientmodel():
+    | ^^^ E302
+963 |     pass
+964 | # end
+    |
+    = help: Add missing blank line(s)
+
+ℹ Safe fix
+958 958 | # E302
+959 959 | def test_update():
+960 960 |     pass
+    961 |+
+    962 |+
+961 963 | # comment
+962 964 | def test_clientmodel():
+963 965 |     pass