Subject: Re: [PATCH 3/4] t5304: Ensure wanted files are not deleted

From: Junio C Hamano <[email-masked]>
Date: Wed, 13 Jan 2016 12:55:50 -0800

Doug Kelly <[email-masked]> writes:

> Subject: Re: [PATCH 3/4] t5304: Ensure wanted files are not deleted

I'd suggest s/wanted/non-garbage/.

> Explicitly test for and ensure files that may be wanted are not
> deleted during a gc operation.  These include .pack without .idx
> (which may be in-flight), garbage in the directory, and .keep files
> the user created.

"garbage in the directory" is not well defined.  "files in the
directory that clearly are not related to packing" is probably what
you meant, but the definition of "related to packing" is still
fuzzy.  Please clarify.

The following is me thinking aloud about things that you would need
to think about while attempting to clarify this.

What should the code do if we find

    pack-b0a9d62a7471e58832a575a78d57f8fb26822125.frotz

in $GIT_OBJECT_DIRECTORY/pack/ directory?  Is it a "garbage in the
directory"?  The filename looks so similar to the usual things with
know suffixes .pack, .idx, .bitmap, and .keep, that we may want to
consider that it might be another file related to the packing left
by a future version of Git and if we do not see corresponding .pack
we would want to remove it?  Or do we want to do something else?

What should "gc" do if we find

    pack-frotz.idx

without corresponding ".pack"?  Wouldn't it be safer to consider it
a garbage unrelated to packing (because regular packing would have
given it with 40-hex name, not "frotz") and leave it undeleted?

Thanks.

> Signed-off-by: Doug Kelly <[email-masked]>
> ---
>  t/t5304-prune.sh | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
>
> diff --git a/t/t5304-prune.sh b/t/t5304-prune.sh
> index 4fa6e7a..f7c380c 100755
> --- a/t/t5304-prune.sh
> +++ b/t/t5304-prune.sh
> @@ -285,6 +285,23 @@ EOF
>  	test_cmp expected actual
>  '
>  
> +test_expect_success 'ensure unknown garbage kept with gc' '
> +	test_when_finished "rm -f .git/objects/pack/fake*" &&
> +	test_when_finished "rm -f .git/objects/pack/foo*" &&
> +	: >.git/objects/pack/foo.keep &&
> +	: >.git/objects/pack/fake.pack &&
> +	: >.git/objects/pack/fake2.foo &&
> +	git gc &&
> +	git count-objects -v 2>stderr &&
> +	grep "^warning:" stderr | sort >actual &&
> +	cat >expected <<\EOF &&
> +warning: garbage found: .git/objects/pack/fake2.foo
> +warning: no corresponding .idx or .pack: .git/objects/pack/foo.keep
> +warning: no corresponding .idx: .git/objects/pack/fake.pack
> +EOF
> +	test_cmp expected actual
> +'
> +
>  test_expect_success 'prune .git/shallow' '
>  	SHA1=`echo hi|git commit-tree HEAD^{tree}` &&
>  	echo $SHA1 >.git/shallow &&