Skip to content

fix msvc linker bug for huge command line arguments #406

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
astrelsky wants to merge 4 commits into
base: main
Choose a base branch
from
Open

fix msvc linker bug for huge command line arguments #406

Changes from 1 commit
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
633d787
fix msvc linker bug for huge command line arguments
astrelsky Mar 29, 2026
646b072
use subprocess.list2cmdline to ensure the full length of the sanitize…
astrelsky Apr 3, 2026
da2f91d
Update distutils/compilers/C/msvc.py
astrelsky Apr 3, 2026
11eb104
changes per review
astrelsky Apr 29, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
14 changes: 13 additions & 1 deletion distutils/compilers/C/msvc.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -15,7 +15,9 @@

import contextlib
import os
from pathlib import Path
import subprocess
import tempfile
import unittest.mock as mock
import warnings
from collections.abc import Iterable
Expand Down Expand Up @@ -551,7 +553,17 @@ def link(
self.mkpath(output_dir)
try:
log.debug('Executing "%s" %s', self.linker, ' '.join(ld_args))
self.spawn([self.linker] + ld_args)
# The maximum length of the commandline is 32,767
# we must pass in the arguments through a file if it is longer
# https://learn.microsoft.com/en-us/cpp/build/reference/linking?view=msvc-170#linker-command-files
# https://learn.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-createprocessa#parameters
if len(' '.join(ld_args)) > 30000:
Comment thread
astrelsky marked this conversation as resolved.
Outdated
with tempfile.TemporaryDirectory() as tmpdir:
Comment thread
astrelsky marked this conversation as resolved.
Outdated
cmdline = Path(tmpdir) / 'cmdline.txt'
cmdline.write_text('\n'.join(f'"{item}"' for item in ld_args))
Comment thread
astrelsky marked this conversation as resolved.
Outdated
self.spawn([self.linker, '@'+str(cmdline)])
Comment thread
astrelsky marked this conversation as resolved.
Outdated
else:
self.spawn([self.linker] + ld_args)
except DistutilsExecError as msg:
raise LinkError(msg)
else:
Expand Down