Merge 8b18899f2d into 665f68036c

crates/ruff_python_formatter/resources/test/fixtures/ruff/statement/if.py

@@ -294,3 +294,39 @@ if parent_body:
       # d
         # e
           #f
+
+# Compare behavior with `while`/`else` comment placement
+
+if True: pass
+    # comment
+else:
+    pass
+
+if True:
+    pass
+        # comment
+else:
+    pass
+
+if True: pass
+# comment
+else:
+    pass
+
+if True: pass
+    # comment
+else:
+    pass
+
+def foo():
+    if True:
+        pass
+# comment
+    else:
+        pass
+
+if True:
+    first;second
+    # comment
+else:
+    pass

crates/ruff_python_formatter/resources/test/fixtures/ruff/statement/while.py

@@ -28,3 +28,37 @@ while (
     and anotherCondition or aThirdCondition  # trailing third condition
 ):  # comment
     print("Do something")
+
+while True: pass
+    # comment
+else:
+    pass
+
+while True:
+    pass
+        # comment
+else:
+    pass
+
+while True: pass
+# comment
+else:
+    pass
+
+while True: pass
+    # comment
+else:
+    pass
+
+def foo():
+    while True:
+        pass
+# comment
+    else:
+        pass
+
+while True:
+    first;second
+    # comment
+else:
+    pass

crates/ruff_python_formatter/src/comments/mod.rs

@@ -1042,4 +1042,33 @@ else: # trailing comment
 
         assert_debug_snapshot!(comments.debug(test_case.source_code));
     }
+
+    #[test]
+    fn while_else_indented_comment_between_branches() {
+        let source = r"while True: pass
+    # comment
+else:
+    pass
+";
+        let test_case = CommentsTestCase::from_code(source);
+
+        let comments = test_case.to_comments();
+
+        assert_debug_snapshot!(comments.debug(test_case.source_code));
+    }
+
+    #[test]
+    fn while_else_very_indented_comment_between_branches() {
+        let source = r"while True:
+    pass
+        # comment
+else:
+    pass
+";
+        let test_case = CommentsTestCase::from_code(source);
+
+        let comments = test_case.to_comments();
+
+        assert_debug_snapshot!(comments.debug(test_case.source_code));
+    }
 }

crates/ruff_python_formatter/src/comments/placement.rs

@@ -8,7 +8,7 @@ use ruff_python_trivia::{
     find_only_token_in_range, first_non_trivia_token, indentation_at_offset,
 };
 use ruff_source_file::LineRanges;
-use ruff_text_size::{Ranged, TextLen, TextRange};
+use ruff_text_size::{Ranged, TextLen, TextRange, TextSize};
 use std::cmp::Ordering;
 
 use crate::comments::visitor::{CommentPlacement, DecoratedComment};
@@ -602,9 +602,35 @@ fn handle_own_line_comment_between_branches<'a>(
     // following branch or if it a trailing comment of the previous body's last statement.
     let comment_indentation = comment_indentation_after(preceding, comment.range(), source);
 
-    let preceding_indentation = indentation(source, &preceding)
-        .unwrap_or_default()
-        .text_len();
+    let preceding_indentation = indentation(source, &preceding).map_or_else(
+        // If `indentation` returns `None`, then there is leading
+        // content before the preceding node. In this case, we
+        // always treat the comment as being less-indented than the
+        // preceding. For example:
+        //
+        // ```python
+        // if True: pass
+        // # leading on `else`
+        // else:
+        //     pass
+        // ```
+        // Note we even do this if the comment is very indented
+        // (which matches `black`'s behavior as of 2025.11.11)
+        //
+        // ```python
+        // if True: pass
+        //          # leading on `else`
+        // else:
+        //     pass
+        // ```
+        || {
+            comment_indentation
+            // This can be any positive number - we just
+            // want to hit the `Less` branch below
+            + TextSize::new(1)
+        },
+        ruff_text_size::TextLen::text_len,
+    );
 
     // Compare to the last statement in the body
     match comment_indentation.cmp(&preceding_indentation) {
@@ -678,8 +704,49 @@ fn handle_own_line_comment_after_branch<'a>(
     preceding: AnyNodeRef<'a>,
     source: &str,
 ) -> CommentPlacement<'a> {
-    let Some(last_child) = preceding.last_child_in_body() else {
-        return CommentPlacement::Default(comment);
+    // If the preceding node has a body, we want the last child - e.g.
+    //
+    // ```python
+    // if True:
+    //     def foo():
+    //         something
+    //         last_child
+    //             # comment
+    // else:
+    //     pass
+    // ```
+    //
+    // Otherwise, the preceding node may be the last statement in the body
+    // of the preceding branch, in which case we can take it as our
+    // `last_child` here - e.g.
+    //
+    // ```python
+    // if True:
+    //     something
+    //     last_child
+    //         # comment
+    // else:
+    //     pass
+    // ```
+    let last_child = match preceding.last_child_in_body() {
+        Some(last) => last,
+        None if matches!(
+            comment.enclosing_node(),
+            AnyNodeRef::StmtIf(_)
+                | AnyNodeRef::StmtWhile(_)
+                | AnyNodeRef::StmtFor(_)
+                | AnyNodeRef::StmtMatch(_)
+                | AnyNodeRef::ElifElseClause(_)
+                | AnyNodeRef::StmtTry(_)
+                | AnyNodeRef::MatchCase(_)
+                | AnyNodeRef::ExceptHandlerExceptHandler(_)
+        ) =>
+        {
+            preceding
+        }
+        _ => {
+            return CommentPlacement::Default(comment);
+        }
     };
 
     // We only care about the length because indentations with mixed spaces and tabs are only valid if

crates/ruff_python_formatter/src/comments/snapshots/ruff_python_formatter__comments__tests__while_else_indented_comment_between_branches.snap

@@ -0,0 +1,21 @@
+---
+source: crates/ruff_python_formatter/src/comments/mod.rs
+expression: comments.debug(test_case.source_code)
+---
+{
+    Node {
+        kind: StmtWhile,
+        range: 0..45,
+        source: `while True: pass⏎`,
+    }: {
+        "leading": [],
+        "dangling": [
+            SourceComment {
+                text: "# comment",
+                position: OwnLine,
+                formatted: false,
+            },
+        ],
+        "trailing": [],
+    },
+}

crates/ruff_python_formatter/src/comments/snapshots/ruff_python_formatter__comments__tests__while_else_very_indented_comment_between_branches.snap

@@ -0,0 +1,21 @@
+---
+source: crates/ruff_python_formatter/src/comments/mod.rs
+expression: comments.debug(test_case.source_code)
+---
+{
+    Node {
+        kind: StmtPass,
+        range: 16..20,
+        source: `pass`,
+    }: {
+        "leading": [],
+        "dangling": [],
+        "trailing": [
+            SourceComment {
+                text: "# comment",
+                position: OwnLine,
+                formatted: false,
+            },
+        ],
+    },
+}

crates/ruff_python_formatter/tests/snapshots/format@form_feed.py.snap

@@ -1,7 +1,6 @@
 ---
 source: crates/ruff_python_formatter/tests/fixtures.rs
 input_file: crates/ruff_python_formatter/resources/test/fixtures/ruff/form_feed.py
-snapshot_kind: text
 ---
 ## Input
 ```python
@@ -18,7 +17,7 @@ else:
 # Regression test for: https://github.com/astral-sh/ruff/issues/7624
 if symbol is not None:
     request["market"] = market["id"]
-#             "remaining_volume": "0.0",
+    #             "remaining_volume": "0.0",
 else:
     pass
 ```

crates/ruff_python_formatter/tests/snapshots/format@statement__if.py.snap

@@ -1,7 +1,6 @@
 ---
 source: crates/ruff_python_formatter/tests/fixtures.rs
 input_file: crates/ruff_python_formatter/resources/test/fixtures/ruff/statement/if.py
-snapshot_kind: text
 ---
 ## Input
 ```python
@@ -301,6 +300,42 @@ if parent_body:
       # d
         # e
           #f
+
+# Compare behavior with `while`/`else` comment placement
+
+if True: pass
+    # comment
+else:
+    pass
+
+if True:
+    pass
+        # comment
+else:
+    pass
+
+if True: pass
+# comment
+else:
+    pass
+
+if True: pass
+    # comment
+else:
+    pass
+
+def foo():
+    if True:
+        pass
+# comment
+    else:
+        pass
+
+if True:
+    first;second
+    # comment
+else:
+    pass
 ```
 
 ## Output
@@ -607,6 +642,48 @@ if parent_body:
 # d
 # e
 # f
+
+# Compare behavior with `while`/`else` comment placement
+
+if True:
+    pass
+# comment
+else:
+    pass
+
+if True:
+    pass
+    # comment
+else:
+    pass
+
+if True:
+    pass
+# comment
+else:
+    pass
+
+if True:
+    pass
+# comment
+else:
+    pass
+
+
+def foo():
+    if True:
+        pass
+    # comment
+    else:
+        pass
+
+
+if True:
+    first
+    second
+# comment
+else:
+    pass
 ```
 
 

crates/ruff_python_formatter/tests/snapshots/format@statement__while.py.snap

@@ -1,7 +1,6 @@
 ---
 source: crates/ruff_python_formatter/tests/fixtures.rs
 input_file: crates/ruff_python_formatter/resources/test/fixtures/ruff/statement/while.py
-snapshot_kind: text
 ---
 ## Input
 ```python
@@ -35,6 +34,40 @@ while (
     and anotherCondition or aThirdCondition  # trailing third condition
 ):  # comment
     print("Do something")
+
+while True: pass
+    # comment
+else:
+    pass
+
+while True:
+    pass
+        # comment
+else:
+    pass
+
+while True: pass
+# comment
+else:
+    pass
+
+while True: pass
+    # comment
+else:
+    pass
+
+def foo():
+    while True:
+        pass
+# comment
+    else:
+        pass
+
+while True:
+    first;second
+    # comment
+else:
+    pass
 ```
 
 ## Output
@@ -70,4 +103,44 @@ while (
     or aThirdCondition  # trailing third condition
 ):  # comment
     print("Do something")
+
+while True:
+    pass
+# comment
+else:
+    pass
+
+while True:
+    pass
+    # comment
+else:
+    pass
+
+while True:
+    pass
+# comment
+else:
+    pass
+
+while True:
+    pass
+# comment
+else:
+    pass
+
+
+def foo():
+    while True:
+        pass
+    # comment
+    else:
+        pass
+
+
+while True:
+    first
+    second
+# comment
+else:
+    pass
 ```