diff mbox series

t7701: make annotated tag unreachable

Message ID 48d3c2c1871c8122d22fbce7c256ca65582fcd67.1687342818.git.me@ttaylorr.com (mailing list archive)
State Superseded
Headers show
Series t7701: make annotated tag unreachable | expand

Commit Message

Taylor Blau June 21, 2023, 10:21 a.m. UTC
In 4dc16e2cb0 (gc: introduce `gc.recentObjectsHook`, 2023-06-07), we
added tests to ensure that prune-able (i.e. unreachable and with mtime
older than the cutoff) objects which are marked as recent via the new
`gc.recentObjectsHook` configuration are unpacked as loose with
`--unpack-unreachable`.

In that test, we also ensure that objects which are reachable from other
unreachable objects which were *not* pruned are kept as well, regardless
of their mtimes. For this, we use an annotated tag pointing at a blob
($obj2) which would otherwise be pruned.

But after pruning, that object is kept around for two reasons. One, the
tag object's mtime wasn't adjusted to be beyond the 1-hour cutoff, so it
would be kept as due to its recency regardless. The other reason is
because the tag itself is reachable.

Use mktag to write the tag object directly without pointing a reference
at it, and adjust the mtime of the tag object to be older than the
cutoff to ensure that our `gc.recentObjectsHook` configuration is
working as intended.

Noticed-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
---
Peff pointed this out to me after the gc.recentObjectsHook stuff was in
'next', but this should go on top. This patch is based off of the tip of
"tb/gc-recent-object-hook".

 t/t7701-repack-unpack-unreachable.sh | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

--
2.40.1.478.g4dc16e2cb0

Comments

Jeff King June 24, 2023, 4:38 a.m. UTC | #1
On Wed, Jun 21, 2023 at 06:21:10AM -0400, Taylor Blau wrote:

> But after pruning, that object is kept around for two reasons. One, the
> tag object's mtime wasn't adjusted to be beyond the 1-hour cutoff, so it
> would be kept as due to its recency regardless. The other reason is
> because the tag itself is reachable.
> 
> Use mktag to write the tag object directly without pointing a reference
> at it, and adjust the mtime of the tag object to be older than the
> cutoff to ensure that our `gc.recentObjectsHook` configuration is
> working as intended.

Thanks, this should fix the problem (which you can notice by making the
recentObjectsHook in the test a noop and seeing that it still passes).

But there's one more thing...

> diff --git a/t/t7701-repack-unpack-unreachable.sh b/t/t7701-repack-unpack-unreachable.sh
> index ba428c18a8..ceb4e805d2 100755
> --- a/t/t7701-repack-unpack-unreachable.sh
> +++ b/t/t7701-repack-unpack-unreachable.sh
> @@ -126,8 +126,19 @@ test_expect_success 'gc.recentObjectsHook' '
>  	git cat-file -p $obj2 &&
>  	git cat-file -p $obj3 &&
> 
> +	# make an unreachable annotated tag object to ensure we rescue objects
> +	# which are reachable from non-pruned unreachable objects
>  	git tag -a -m tag obj2-tag $obj2 &&
> -	obj2_tag="$(git rev-parse obj2-tag)" &&
> +	obj2_tag="$(git mktag <<-EOF
> +	object $obj2
> +	type blob
> +	tag obj2-tag
> +	tagger T A Gger <tagger@example.com> 1234567890 -0000
> +	EOF
> +	)" &&

Since we are using "mktag" here, the call to "git tag" can go away
entirely. It's not only redundant, but it erroneously keeps reachability
to $obj2. The test still does something useful (it makes sure that
$obj2_tag was saved), but it is failing to test what it wanted to about
$obj2, namely that it is kept because the hook mentioned an object that
points to it.

So we'd want to squash in:

diff --git a/t/t7701-repack-unpack-unreachable.sh b/t/t7701-repack-unpack-unreachable.sh
index ceb4e805d2..fe6c3e77a3 100755
--- a/t/t7701-repack-unpack-unreachable.sh
+++ b/t/t7701-repack-unpack-unreachable.sh
@@ -128,7 +128,6 @@ test_expect_success 'gc.recentObjectsHook' '
 
 	# make an unreachable annotated tag object to ensure we rescue objects
 	# which are reachable from non-pruned unreachable objects
-	git tag -a -m tag obj2-tag $obj2 &&
 	obj2_tag="$(git mktag <<-EOF
 	object $obj2
 	type blob

-Peff
diff mbox series

Patch

diff --git a/t/t7701-repack-unpack-unreachable.sh b/t/t7701-repack-unpack-unreachable.sh
index ba428c18a8..ceb4e805d2 100755
--- a/t/t7701-repack-unpack-unreachable.sh
+++ b/t/t7701-repack-unpack-unreachable.sh
@@ -126,8 +126,19 @@  test_expect_success 'gc.recentObjectsHook' '
 	git cat-file -p $obj2 &&
 	git cat-file -p $obj3 &&

+	# make an unreachable annotated tag object to ensure we rescue objects
+	# which are reachable from non-pruned unreachable objects
 	git tag -a -m tag obj2-tag $obj2 &&
-	obj2_tag="$(git rev-parse obj2-tag)" &&
+	obj2_tag="$(git mktag <<-EOF
+	object $obj2
+	type blob
+	tag obj2-tag
+	tagger T A Gger <tagger@example.com> 1234567890 -0000
+	EOF
+	)" &&
+
+	obj2_tag_pack="$(echo $obj2_tag | git pack-objects .git/objects/pack/pack)" &&
+	git prune-packed &&

 	write_script precious-objects <<-EOF &&
 	echo $obj2_tag
@@ -136,6 +147,7 @@  test_expect_success 'gc.recentObjectsHook' '

 	test-tool chmtime =-86400 .git/objects/pack/pack-$pack2.pack &&
 	test-tool chmtime =-86400 .git/objects/pack/pack-$pack3.pack &&
+	test-tool chmtime =-86400 .git/objects/pack/pack-$obj2_tag_pack.pack &&
 	git repack -A -d --unpack-unreachable=1.hour.ago &&

 	git cat-file -p $obj1 &&