Subject: Re: [PATCH] prune: quiet ENOENT on missing directories

From: Junio C Hamano <[email-masked]>
Date: Mon, 21 Nov 2022 15:02:31 +0900

Eric Wong <[email-masked]> writes:

> $GIT_DIR/objects/pack may be removed to save inodes in shared
> repositories.  Quiet down prune in cases where either
> $GIT_DIR/objects or $GIT_DIR/objects/pack is non-existent,

Wouldn't setup.c::is_git_directory() say "nope, you do not have a
repository there" if you are missing $GIT_DIR/objects?  So I suspect
that the only case this matters in practice is a missing pack/
subdirectory.

I agree that silently ignoring missing objects/pack/ is perfectly
fine, whether we auto-vivify it when we actually create a pack.

> but emit the system error in other cases to help users diagnose
> permissions problems or resource constraints.

OK.

> @@ -127,7 +127,9 @@ static void remove_temporary_files(const char *path)
>  
>  	dir = opendir(path);
>  	if (!dir) {
> -		fprintf(stderr, "Unable to open directory %s\n", path);
> +		if (errno != ENOENT)
> +			fprintf(stderr, "Unable to open directory %s: %s\n",
> +				path, strerror(errno));
>  		return;
>  	}

This is called twice, with $GIT_OBJECT_DIRECTORY and its pack
subdirectory, as it does not recurse.  

This is a tangent, I have to wonder how effective the first call
would be, though.  When writing a loose object file, we compute its
object name first in-core and determine the final filename, create a
temporary file in the same directory as the final file, write into
it and then finally rename the temporary to the final name.  The
fan-out $GIT_OBJECT_DIRECTORY/??/ directories may have temporary
files left when such a process crashed, but do we create cruft "git
prune" should remove in $GIT_OBJECT_DIRECTORY/ itself?

> diff --git a/t/t5304-prune.sh b/t/t5304-prune.sh
> index 8ae314af58..d65a5f94b4 100755
> --- a/t/t5304-prune.sh
> +++ b/t/t5304-prune.sh
> @@ -29,6 +29,14 @@ test_expect_success setup '
>  	git gc
>  '
>  
> +test_expect_success 'bare repo prune is quiet without $GIT_DIR/objects/pack' '
> +	git clone -q --shared --template= --bare . bare.git &&
> +	rmdir bare.git/objects/pack &&
> +	git --git-dir=bare.git prune --no-progress 2>prune.err &&
> +	test_must_be_empty prune.err &&
> +	rm -r bare.git prune.err
> +'
> +
>  test_expect_success 'prune stale packs' '
>  	orig_pack=$(echo .git/objects/pack/*.pack) &&
>  	>.git/objects/tmp_1.pack &&