Describe the bug

This is the exact same bug as #3605 . The original issue did not provide a suggestion on how to resolve the issue.

blib2to3.pytree.Leaf.bracket_depth is annotated as int, but it's never initialized. In black.lines.is_line_short_enough, if leaf.bracket_depth + 1 > len(commas): --> AttributeError.

The resulting error is:

Traceback (most recent call last):
File "/mnt/sda1/dev_parent/logging_strict/.venv/lib/python3.10/site-packages/black/init.py", line 939, in reformat_one
if changed is not Changed.CACHED and format_file_in_place(
File "/mnt/sda1/dev_parent/logging_strict/.venv/lib/python3.10/site-packages/black/init.py", line 982, in format_file_in_place
dst_contents = format_file_contents(
File "/mnt/sda1/dev_parent/logging_strict/.venv/lib/python3.10/site-packages/black/init.py", line 1118, in format_file_contents
dst_contents = format_str(src_contents, mode=mode, lines=lines)
File "/mnt/sda1/dev_parent/logging_strict/.venv/lib/python3.10/site-packages/black/init.py", line 1247, in format_str
dst_contents = _format_str_once(src_contents, mode=mode, lines=lines)
File "/mnt/sda1/dev_parent/logging_strict/.venv/lib/python3.10/site-packages/black/init.py", line 1306, in _format_str_once
for line in transform_line(
File "/mnt/sda1/dev_parent/logging_strict/.venv/lib/python3.10/site-packages/black/linegen.py", line 746, in transform_line
is_line_short_enough(line, mode=mode, line_str=line_str_hugging_power_ops)
File "/mnt/sda1/dev_parent/logging_strict/.venv/lib/python3.10/site-packages/black/lines.py", line 1279, in is_line_short_enough
if leaf.bracket_depth + 1 > len(commas):
AttributeError: 'Leaf' object has no attribute 'bracket_depth'
error: cannot format tests/test_registry_config.py: 'Leaf' object has no attribute 'bracket_depth'

Expected behavior

In blib2to3.pytree.Leaf.init explicitly initialize attributes: bracket_depth and opening_bracket.

Run black patched

python run_black.py tests/test_registry_config.py --verbose --diff --target-version=py310

import sys
from blib2to3.pytree import Leaf

# Patch first
if not hasattr(Leaf, '_original_init'):
    Leaf._original_init = Leaf.__init__
    def patched_init(self, *args, **kwargs):
        Leaf._original_init(self, *args, **kwargs)
        self.bracket_depth = 0
        self.opening_bracket = None
    Leaf.__init__ = patched_init

# Import and run Black
from black import patched_main
sys.argv[0] = "black"
sys.exit(patched_main())

Environment

• Black's version: 26.5.1
• OS and Python version: Linux py310