The `os.execv*` family has problems with strings on Windows

[chris-eibl]

Bug report

Bug description:

import os
import sys

args = [sys.executable, '-c', 'print("hello from execve")']
os.execve(args[0], args, {})

results in

    print(hello from execve)
                ^^^^
SyntaxError: invalid syntax

Using

args = [sys.executable, '-c', "print('hello from execve')"]

results in

    print('hello
          ^
SyntaxError: unterminated string literal (detected at line 1)

Both work like expected in WSL or native Ubuntu.

The only thing that somewhat works is omitting the spaces "print('hellofromexecve')" in the second case.

3.15 back to and including 3.10 are affected.

CPython versions tested on:

CPython main branch

Operating systems tested on:

Windows

[picnixz]

Actually, I wonder the problem is the strings or whether it's the command-line itself. I remember that using ' doesn't work well in CMD.exe or something like that (e.g., python -c 'print("a")' fails IIRC).

[gvanrossum]

Shouldn't we just recommend the subprocess module?

[oskar-skog]

I'm surprised the exec class of functions even exists on Windows.

It looks like it's a bug in Microsoft's CRT, CPython isn't doing anything funny with exec* on Windows:
https://github.com/python/cpython/blob/main/Modules/posixmodule.c#L7567
It just calls _wexec*.

See also #101191

[chris-eibl]

Actually, I wonder the problem is the strings or whether it's the command-line itself

Yupp. It must be correctly escaped. This works:

args = [sys.executable, '-c', "\"print('hello from execve')\""]

Escaping could be handled in

cpython/Modules/posixmodule.c

Line 7543 in 513ae17

argvlist = parse_arglist(argv, &argc);

Given this hasn't been an issue on Windows so far (the execv* family isn't quite popular here) and we've only stumbled over it recently when writing a test (#143314 (comment)), maybe just close this?

[picnixz]

Yes, let's close it. We can't do anything :(