Possibly wrong command line split behavior on Windows

[akaihola]

(This issue was moved from akaihola/darker#456 together with the linting support implementation.)

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A full linter command line can be provided to Darker, e.g.

darker --lint="mypy --strict" .

Splitting that command line into parts is done using shlex.split(), and on Windows the posix=False argument is added so backslashes as directory separators work correctly (todo: check this, not 100% sure).

This works otherwise as expected, but if there's a quoted parameter, the quotes don't get stripped properly:

>>> import shlex
>>> shlex.split('pylint --ignore "setup.py"')
['pylint', '--ignore', '"setup.py"']  # on Windows

which is different from how it behaves on Unix.

A test xfail on Windows is added to test_check_linter_output() to mark this as a known issue but have the test suite still pass.

I'm not sure if the quotes are still removed correctly on Windows.

[akaihola]

GitHub Copilot suggests this:

You can use the subprocess module's list2cmdline function to split the command line string in a way that's compatible with Windows command line parsing rules. Here's an example:

import subprocess
import shlex

def split_command(command):
   if subprocess.mswindows:
       return shlex.split(subprocess.list2cmdline(shlex.split(command, posix=False)))
   else:
       return shlex.split(command)

print(split_command('a "b"'))  # Outputs: ['a', 'b']

In this example, split_command function first checks if the current system is Windows. If it is, it uses subprocess.list2cmdline to convert the command line string into a format that's compatible with Windows command line parsing rules, and then splits it using shlex.split with posix=False. If the system is not Windows, it simply splits the command line string using shlex.split.