From 40407dcce52eaf760cfe38590b8d5273d4b8b98e Mon Sep 17 00:00:00 2001
From: Charlie Marsh <charlie.r.marsh@gmail.com>
Date: Mon, 14 Aug 2023 09:52:19 -0400
Subject: [PATCH] Avoid marking inner-parenthesized comments as dangling
 bracket comments (#6517)

## Summary

The bracketed-end-of-line comment rule is meant to assign comments like
this as "immediately following the bracket":

```python
f(  # comment
    1
)
```

However, the logic was such that we treated this equivalently:

```python
f(
    (  # comment
        1
    )
)
```

This PR modifies the placement logic to ensure that we only skip the
opening bracket, and not any nested brackets. The above is now formatted
as:

```python
f(
    (
        # comment
        1
    )
)
```

(But will be corrected once we handle parenthesized comments properly.)

## Test Plan

`cargo test`

Confirmed no change in similarity score.
---
 .../test/fixtures/ruff/expression/call.py     |  6 ++++++
 .../src/comments/placement.rs                 | 20 ++++++++++++-------
 .../snapshots/format@expression__call.py.snap | 13 ++++++++++++
 3 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/crates/ruff_python_formatter/resources/test/fixtures/ruff/expression/call.py b/crates/ruff_python_formatter/resources/test/fixtures/ruff/expression/call.py
index 82166ba564..03502701ec 100644
--- a/crates/ruff_python_formatter/resources/test/fixtures/ruff/expression/call.py
+++ b/crates/ruff_python_formatter/resources/test/fixtures/ruff/expression/call.py
@@ -115,3 +115,9 @@ f (
 threshold_date = datetime.datetime.now() - datetime.timedelta(  # comment
     days=threshold_days_threshold_days
 )
+
+f(
+    (  # comment
+        1
+    )
+)
diff --git a/crates/ruff_python_formatter/src/comments/placement.rs b/crates/ruff_python_formatter/src/comments/placement.rs
index d55ec6c91b..d8d8c03578 100644
--- a/crates/ruff_python_formatter/src/comments/placement.rs
+++ b/crates/ruff_python_formatter/src/comments/placement.rs
@@ -1150,14 +1150,20 @@ fn handle_bracketed_end_of_line_comment<'a>(
             locator.contents(),
             TextRange::new(comment.enclosing_node().start(), comment.start()),
         )
-        .skip_trivia()
-        .skip_while(|t| {
-            matches!(
-                t.kind(),
-                SimpleTokenKind::LParen | SimpleTokenKind::LBrace | SimpleTokenKind::LBracket
-            )
-        });
+        .skip_trivia();
 
+        // Skip the opening parenthesis.
+        let Some(paren) = lexer.next() else {
+            return CommentPlacement::Default(comment);
+        };
+        debug_assert!(matches!(
+            paren.kind(),
+            SimpleTokenKind::LParen | SimpleTokenKind::LBrace | SimpleTokenKind::LBracket
+        ));
+
+        // If there are no additional tokens between the open parenthesis and the comment, then
+        // it should be attached as a dangling comment on the brackets, rather than a leading
+        // comment on the first argument.
         if lexer.next().is_none() {
             return CommentPlacement::dangling(comment.enclosing_node(), comment);
         }
diff --git a/crates/ruff_python_formatter/tests/snapshots/format@expression__call.py.snap b/crates/ruff_python_formatter/tests/snapshots/format@expression__call.py.snap
index 283a06b31a..b6dab5b5df 100644
--- a/crates/ruff_python_formatter/tests/snapshots/format@expression__call.py.snap
+++ b/crates/ruff_python_formatter/tests/snapshots/format@expression__call.py.snap
@@ -121,6 +121,12 @@ f (
 threshold_date = datetime.datetime.now() - datetime.timedelta(  # comment
     days=threshold_days_threshold_days
 )
+
+f(
+    (  # comment
+        1
+    )
+)
 ```
 
 ## Output
@@ -241,6 +247,13 @@ f(
 threshold_date = datetime.datetime.now() - datetime.timedelta(  # comment
     days=threshold_days_threshold_days
 )
+
+f(
+    (
+        # comment
+        1
+    )
+)
 ```