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Inspecting the index during a pre-commit is empty #1388
Description
I've written a small script to work with pre-commit, which when run locally seems to work but when I run it through pre-commit the git index is empty and I get errors.
The issue I'm seeing is when I run the script via PyCharm the checks pass, but when it's run automatically by pre-commit the meta_file_in_index fails because the index appears to be empty.
Any advice on what I'm doing wrong or suggestions for digging deeper into what's going on would be greatly appreciated.
What I've done so far:
- Validated it's the right path
- Validating it's on the same branch
The issue raised with pre-commit: pre-commit/pre-commit#2184
Source Code:
#!/usr/bin/env python3
import os
import sys
from git import Repo, IndexFile, DiffIndex
def filter_assets(path: str):
lower_case = path.lower()
return lower_case.startswith("assets")
def path_to_meta_file(path: str):
return path + ".meta"
def meta_file_exists(meta_file: str):
return os.path.isfile(meta_file)
def meta_file_in_index(meta_file: str, index: IndexFile):
return any(x for x in index.entries.keys() if x[0] == meta_file)
def meta_file_in_diff(meta_file: str, diff: DiffIndex):
return any(x for x in diff if x.a_path == meta_file)
def run():
files = [path for path in sys.argv[1:] if filter_assets(path)]
print(os.getcwd())
repo = Repo(os.getcwd())
index = repo.index
modified = index.diff(None)
errors = []
for file in files:
meta_file = path_to_meta_file(file)
if not meta_file_exists(meta_file):
errors.append(f"{file} does not have a matching meta file {meta_file}")
continue
if not meta_file_in_index(meta_file, index):
errors.append(f"{meta_file} is not in the git index")
continue
if meta_file_in_diff(meta_file, modified):
errors.append(f"{meta_file} has been changed but is not staged")
if len(errors) > 0:
print("At least one file has an issue with it's meta file:")
print(" * " + "\n * ".join(errors))
sys.exit(1)
if __name__ == "__main__":
run()
Activity
Byron commentedon Jan 6, 2022
Thanks for the clear issue description, very informative!
It's not the first time I hear that git hooks aren't working as they should depending on how executes them. Most often they fail in cron jobs though.
Since the
indexappears to be empty, I can imagine it get the wrong path. Now it's mentioned that the 'right path' was validated already, so is it correct that that repo.git_dir is what it should be?If it is, you might try to re-throw this OSError as it's the only reason it would yield an empty index. Unfortunately it doesn't check the actual cause of the error, it should only yield an empty index if the file isn't present yet, which should barely ever be happening.
robin-moss commentedon Jan 6, 2022
So adding the code:
led to a stack trace (below), which mentions that there is already an
index.lock, which would actually make sense as we're in a "pre-commit" hook so in the middle of a Git operation 🤦. Is it possible to run in a "readonly" state that wouldn't require the index lock?Otherwise I'll have to reconsider my approach to checking the index
Stack trace:
Byron commentedon Jan 7, 2022
I have created a new release which simply won't take a read lock anymore - it's not required at all, to solve this particular problem.
robin-moss commentedon Jan 7, 2022
Thank you, that fixed my issue :)