Fix a string merging/split issue caused by standalone comments. (#3227)

[etc/vim.git] / src / black / lines.py

diff --git a/src/black/lines.py b/src/black/lines.py
index 8b591c324a5da6a27fc7fb7613f2900df2da9b7b..30622650d53cd631cdcb800ce8e2a546b0de6840 100644 (file)
--- a/src/black/lines.py
+++ b/src/black/lines.py
@@ -1,6 +1,6 @@
-from dataclasses import dataclass, field
 import itertools
 import sys
+from dataclasses import dataclass, field
 from typing import (
     Callable,
     Dict,
@@ -13,16 +13,25 @@ from typing import (
     cast,
 )
 
-from blib2to3.pytree import Node, Leaf
-from blib2to3.pgen2 import token
-
-from black.brackets import BracketTracker, DOT_PRIORITY
+from black.brackets import DOT_PRIORITY, BracketTracker
 from black.mode import Mode, Preview
-from black.nodes import STANDALONE_COMMENT, TEST_DESCENDANTS
-from black.nodes import BRACKETS, OPENING_BRACKETS, CLOSING_BRACKETS
-from black.nodes import syms, whitespace, replace_child, child_towards
-from black.nodes import is_multiline_string, is_import, is_type_comment
-from black.nodes import is_one_sequence_between
+from black.nodes import (
+    BRACKETS,
+    CLOSING_BRACKETS,
+    OPENING_BRACKETS,
+    STANDALONE_COMMENT,
+    TEST_DESCENDANTS,
+    child_towards,
+    is_import,
+    is_multiline_string,
+    is_one_sequence_between,
+    is_type_comment,
+    replace_child,
+    syms,
+    whitespace,
+)
+from blib2to3.pgen2 import token
+from blib2to3.pytree import Leaf, Node
 
 # types
 T = TypeVar("T")
@@ -264,6 +273,8 @@ class Line:
         - it's not a single-element subscript
         Additionally, if ensure_removable:
         - it's not from square bracket indexing
+        (specifically, single-element square bracket indexing with
+        Preview.skip_magic_trailing_comma_in_subscript)
         """
         if not (
             closing.type in CLOSING_BRACKETS
@@ -292,8 +303,22 @@ class Line:
 
             if not ensure_removable:
                 return True
+
             comma = self.leaves[-1]
-            return bool(comma.parent and comma.parent.type == syms.listmaker)
+            if comma.parent is None:
+                return False
+            if Preview.skip_magic_trailing_comma_in_subscript in self.mode:
+                return (
+                    comma.parent.type != syms.subscriptlist
+                    or closing.opening_bracket is None
+                    or not is_one_sequence_between(
+                        closing.opening_bracket,
+                        closing,
+                        self.leaves,
+                        brackets=(token.LSQB, token.RSQB),
+                    )
+                )
+            return comma.parent.type == syms.listmaker
 
         if self.is_import:
             return True