git.cmd.Git.execute(..): fix with_stdout=False#2126
git.cmd.Git.execute(..): fix with_stdout=False#2126ngie-eign wants to merge 2 commits intogitpython-developers:mainfrom
with_stdout=False#2126Conversation
In the event the end-user called one of the APIs with `with_stdout=False`, i.e., they didn't want to capture stdout, the code would crash with an AttributeError or ValueError when trying to dereference the stdout/stderr streams attached to `Popen(..)` objects. Be more defensive by checking the streams first to make sure they're not `None` before trying to access their corresponding attributes. Add myself to AUTHORS and add corresponding regression tests for the change. Signed-off-by: Enji Cooper <yaneurabeya@gmail.com>
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Prior to this the test would fail [silently] on my macOS host during the test and then pytest would complain loudly about it being an issue post-session (regardless of whether or not the test was being run). Squash the unwritable directory to mute noise complaints from pytest. Signed-off-by: Enji Cooper <yaneurabeya@gmail.com>
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Thanks a lot. This looks good to me.
If the machine doesn't find anything horrendous, we can merge this.
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Pull request overview
Fixes Git.execute(..., with_stdout=False) crashing when stdout/stderr streams are None, and adds regression coverage to prevent future regressions.
Changes:
- Make
Git.execute()defensive againstNonestdout/stderr streams when stripping newlines, copying output, and closing handles. - Add regression tests for
with_stdout=Falsescenarios (with and withoutoutput_stream). - Add contributor entry to
AUTHORSand improve test cleanup robustness inrmtreetests.
Reviewed changes
Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.
| File | Description |
|---|---|
git/cmd.py |
Adds None checks around stdout/stderr usage to avoid crashes when stdout isn’t piped. |
test/test_git.py |
Adds regression tests covering with_stdout=False behavior. |
test/test_util.py |
Adds a pytest finalizer to ensure temp directories are cleaned up on platforms with stricter permissions. |
AUTHORS |
Adds a new contributor entry. |
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| if symlink.exists(): | ||
| symlink.chmod(rwx) |
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preen_dir2() calls symlink.chmod(rwx), but Path.chmod() follows symlinks on most platforms and will change the permissions of the target file (dir1 / "file"). That undermines the intent of this test (avoiding permission changes outside dir2) and can leave surprising side effects in the temp tree. Consider removing the symlink chmod entirely (only dir2.chmod(rwx) is needed for cleanup), or if you really need it, use follow_symlinks=False with a best-effort fallback.
| if symlink.exists(): | |
| symlink.chmod(rwx) |
| max_chunk_size = max_chunk_size if max_chunk_size and max_chunk_size > 0 else io.DEFAULT_BUFFER_SIZE | ||
| stream_copy(proc.stdout, output_stream, max_chunk_size) | ||
| stdout_value = proc.stdout.read() | ||
| stderr_value = proc.stderr.read() | ||
| if proc.stdout is not None: | ||
| stream_copy(proc.stdout, output_stream, max_chunk_size) | ||
| stdout_value = proc.stdout.read() | ||
| if proc.stderr is not None: | ||
| stderr_value = proc.stderr.read() |
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In the output_stream branch, if with_stdout=False then proc.stdout will be None, so stdout_value stays as the initial b"" and the method can return an empty string/bytes even though stdout was intentionally not captured. For consistency with the communicate() path (where stdout becomes None), explicitly set stdout_value = None when proc.stdout is None (and update the local typing/overloads accordingly, since stdout can now be None when with_stdout=False).
| # Strip trailing "\n". | ||
| if stdout_value.endswith(newline) and strip_newline_in_stdout: # type: ignore[arg-type] | ||
| if stdout_value is not None and stdout_value.endswith(newline) and strip_newline_in_stdout: # type: ignore[arg-type] | ||
| stdout_value = stdout_value[:-1] | ||
| if stderr_value.endswith(newline): # type: ignore[arg-type] | ||
| if stderr_value is not None and stderr_value.endswith(newline): # type: ignore[arg-type] | ||
| stderr_value = stderr_value[:-1] |
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The new stdout_value is not None / stderr_value is not None guards indicate communicate() can return None (e.g., when with_stdout=False). However, stdout_value/stderr_value are currently annotated as non-optional and the execute() overloads/return type don’t include None for stdout. Updating those annotations to reflect Optional[...] (and the with_extended_output tuple element types) would prevent type-checking mismatches and better document the API behavior.
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Yes, we should definitely find a solution for this. Maybe a type change might already do the trick.
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I tried fudging around with types, but it's really messy dealing with these issues. I quite frankly think that the whole subprocess interface could be simplified with 3.8+'s version of subprocess... give me a bit of time and I'll noodle on how to do that.
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Also, the pre-3.10 type hints are cringy... do you have to support pre-3.8, even though 3.8 has been technically EOL upstream for the past 1~1.5 years?
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I don't like the typing and would be happy to streamline them if there is a choice.
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Also sounds good to update to 3.8+ version of subprocess, if all this helps with types.
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Needs auto-review comments to be addressed.
In the event the end-user called one of the APIs with
with_stdout=False, i.e., they didn't want to capture stdout, the code would crash with an AttributeError or ValueError when trying to dereference the stdout/stderr streams attached toPopen(..)objects.Be more defensive by checking the streams first to make sure they're not
Nonebefore trying to access their corresponding attributes.Add myself to AUTHORS and add corresponding regression tests for the change.