Empty .git/hooks/pre-commit.legacy File causes OSError

[BigTuna94]

search tried in the issue tracker

is:issue is:open OSError

describe your issue

In the latest version (2.19.0) pre-commit install appears to create an empty .git/hooks/pre-commit.legacy file. This causes an OSError when git (version 2.31.1) attempts to run the actual pre-commit hook.

Actual reported error:

$ git commit -m "dummy commit"
An unexpected error has occurred: OSError: [Errno 8] Exec format error: '/<repo path>/.git/hooks/pre-commit.legacy'

This appears to be the same core issue as: #1350
If I manually modify the empty file and add a shebang, the error subsides. However, the real solution is probably to avoid the creation of the empty file altogether.

pre-commit --version

pre-commit 2.19.0

.pre-commit-config.yaml

repos:
-   repo: local
    hooks:
    -   id: clang-format
        name: Enforce code style format
        language: system
        entry: make format-check-staged-silent

~/.cache/pre-commit/pre-commit.log (if present)

version information

pre-commit version: 2.19.0
git --version: git version 2.31.1
sys.version:
    3.9.7 (default, Sep 21 2021, 00:13:39) 
    [GCC 8.5.0 20210514 (Red Hat 8.5.0-3)]
sys.executable: /root/.local/pipx/venvs/pre-commit/bin/python
os.name: posix
sys.platform: linux

error information

An unexpected error has occurred: OSError: [Errno 8] Exec format error: '/<repo path>/.git/hooks/pre-commit.legacy'

Traceback (most recent call last):
  File "/root/.local/pipx/venvs/pre-commit/lib64/python3.9/site-packages/pre_commit/error_handler.py", line 73, in error_handler
    yield
  File "/root/.local/pipx/venvs/pre-commit/lib64/python3.9/site-packages/pre_commit/main.py", line 361, in main
    return hook_impl(
  File "/root/.local/pipx/venvs/pre-commit/lib64/python3.9/site-packages/pre_commit/commands/hook_impl.py", line 232, in hook_impl
    retv, stdin = _run_legacy(hook_type, hook_dir, args)
  File "/root/.local/pipx/venvs/pre-commit/lib64/python3.9/site-packages/pre_commit/commands/hook_impl.py", line 43, in _run_legacy
    return subprocess.run(cmd, input=stdin).returncode, stdin
  File "/usr/lib64/python3.9/subprocess.py", line 505, in run
    with Popen(*popenargs, **kwargs) as process:
  File "/usr/lib64/python3.9/subprocess.py", line 951, in __init__
    self._execute_child(args, executable, preexec_fn, close_fds,
  File "/usr/lib64/python3.9/subprocess.py", line 1821, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)
OSError: [Errno 8] Exec format error: '/<repo path>/.git/hooks/pre-commit.legacy'

[asottile]

how did that file get there to begin with? do you have reproduction steps?

[BigTuna94]

With the listed config file in place, all I did was pre-commit install, which created the file.

[asottile]

I can't reproduce -- the only way that would happen is if you already had created an (invalid) empty .git/hooks/pre-commit file

[BigTuna94]

Hmmm now that I removed the empty file, I cannot reproduce myself... perhaps the empty file was created by an OS/NAS issue...

However, when the empty .git/hooks/pre-commit.legacy file did exist, I could avoid this issue by downgrading to pre-commit==2.18.0. Then when switching back to pre-commit==2.19.0, the issue returned.

[asottile]

I don't think that's accurate either -- nothing changed in hook-impl between those two versions that'd be relevant (and having that file present, empty and executable shows the same error in all those cases): https://github.com/pre-commit/pre-commit/compare/v2.18.0..v2.19.0#diff-c8d43e2e621a124c4518d87dd3a9e598261fcbb4947ea379d84f7f4eeada0238

either way -- this is a user error and not a pre-commit issue

[jtlz2]

If this is a user error, does anyone have a solution? Thanks!

[asottile]

delete the empty file