[PATCH v1] commit-graph.c: no lazy fetch in lookup_commit_in_graph()

[Han Xin <hanxin.hx@bytedance.com>]

If a commit is in the commit graph, we would expect the commit to also
be present. So we should use has_object() instead of
repo_has_object_file(), which will help us avoid getting into an endless
loop of lazy fetch.

We can see the endless loop issue via this[1].

1. https://lore.kernel.org/git/20220612161707.21807-1-chiyutianyi@gmail.com/

Signed-off-by: Han Xin <hanxin.hx@bytedance.com>
---
 commit-graph.c                             |  2 +-
 t/t5329-no-lazy-fetch-with-commit-graph.sh | 50 ++++++++++++++++++++++
 2 files changed, 51 insertions(+), 1 deletion(-)
 create mode 100755 t/t5329-no-lazy-fetch-with-commit-graph.sh

diff --git a/commit-graph.c b/commit-graph.c
index 2b52818731..2dd9bcc7ea 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -907,7 +907,7 @@ struct commit *lookup_commit_in_graph(struct repository *repo, const struct obje
 		return NULL;
 	if (!search_commit_pos_in_graph(id, repo->objects->commit_graph, &pos))
 		return NULL;
-	if (!repo_has_object_file(repo, id))
+	if (!has_object(repo, id, 0))
 		return NULL;
 
 	commit = lookup_commit(repo, id);
diff --git a/t/t5329-no-lazy-fetch-with-commit-graph.sh b/t/t5329-no-lazy-fetch-with-commit-graph.sh
new file mode 100755
index 0000000000..ea5940b9f1
--- /dev/null
+++ b/t/t5329-no-lazy-fetch-with-commit-graph.sh
@@ -0,0 +1,50 @@
+#!/bin/sh
+
+test_description='test for no lazy fetch with the commit-graph'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	git init --bare dest.git &&
+	test_commit one &&
+	git checkout -b tmp &&
+	test_commit two &&
+	git push dest.git --all
+'
+
+test_expect_success 'prepare a alternates repository without commit two' '
+	git clone --bare dest.git alternates &&
+	oid=$(git -C alternates rev-parse refs/heads/tmp) &&
+	git -C alternates update-ref -d refs/heads/tmp &&
+	git -C alternates gc --prune=now &&
+	pack=$(echo alternates/objects/pack/*.pack) &&
+	git verify-pack -v "$pack" >have &&
+	! grep "$oid" have
+'
+
+test_expect_success 'prepare a repository with a commit-graph contains commit two' '
+	git init source &&
+	echo "$(pwd)/dest.git/objects" >source/.git/objects/info/alternates &&
+	git -C source remote add origin "$(pwd)/dest.git" &&
+	git -C source config remote.origin.promisor true &&
+	git -C source config remote.origin.partialclonefilter blob:none &&
+	# the source repository has the whole refs contains refs/heads/tmp
+	git -C source fetch origin &&
+	(
+		cd source &&
+		test_commit three &&
+		git -c gc.writeCommitGraph=true gc
+	)
+'
+
+test_expect_success 'change the alternates of source to that without commit two' '
+	# now we have a commit-graph in the source repository but without the commit two
+	echo "$(pwd)/alternates/objects" >source/.git/objects/info/alternates
+'
+
+test_expect_success 'fetch the missing commit' '
+	git -C source fetch origin $oid 2>fetch.out &&
+	grep "$oid" fetch.out
+'
+
+test_done
-- 
2.36.1