black breaks long statement within [] and not around and

[bbkane]

Describe the bug A clear and concise description of what the bug is.

black replaces:

            is_standard_front_matter = (lines[0] == lines[3] == "---\n") and lines[1] == "layout: default\n"

with

            is_standard_front_matter = (lines[0] == lines[3] == "---\n") and lines[
                1
            ] == "layout: default\n"

It's subjective (and apologies if this should be a style issue, not a bug), but because the and has lower precedence than the conditionals around it, I would find it easier to read if black created teh newline around the and:

            is_standard_front_matter = (lines[0] == lines[3] == "---\n") \
                and lines[1] == "layout: default\n"

This does require a backslash, so reasonable people could disagree :) . I skimmed black's style guide, but didn't see a case representing this. Please close this issue if I'm mistaken about this as a bug.

To Reproduce Steps to reproduce the behavior:

1. Take this file '...'

lines = [
    "---\n",
    "layout: default\n",
    "title: my title\n",
    "---\n",
]


def need_indent():
    def need_more_indent():
        def even_more_indent():
            is_standard_front_matter = (lines[0] == lines[3] == "---\n") and lines[1] == "layout: default\n"

2. Run Black on it with these arguments '....'

$ cat tmp.py| black -
#!/usr/bin/env python3
# -*- coding: utf-8 -*-

lines = [
    "---\n",
    "layout: default\n",
    "title: my title\n",
    "---\n",
]


def need_indent():
    def need_more_indent():
        def even_more_indent():
            is_standard_front_matter = (lines[0] == lines[3] == "---\n") and lines[
                1
            ] == "layout: default\n"
reformatted -
All done! ✨ 🍰 ✨
1 file reformatted.

3. See error

            is_standard_front_matter = (lines[0] == lines[3] == "---\n") and lines[
                1
            ] == "layout: default\n"

Environment (please complete the following information):

• Version: 20.8b1
• OS and Python version: MacOS/Python 3.8.7

Does this bug also happen on master? To answer this, you have two options:
See the black playground

Additional context Add any other context about the problem here.

[JelleZijlstra]

Duplicate of #236