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[PATCH v2 2/2] commit-graph.c: no lazy fetch in lookup_commit_in_graph()

From
Han Xin <hanxin.hx@bytedance.com>
Date
Jun 24, 2022, 05:27 UTC
Message-ID
<d3a99a5c5ae538b626e04d7069dd2fc316605dfc.1656044659.git.hanxin.hx@bytedance.com>
In-Reply-To
<cover.1656044659.git.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.

When we found the commit in the graph in lookup_commit_in_graph(), but the commit is missing from the repository, we will try promisor_remote_get_direct() and then enter another loop. While sometimes it will finally succeed because it cannot fork subprocess, it has exhausted the local process resources and can be harmful to the remote service.

Signed-off-by: Han Xin <hanxin.hx@bytedance.com>
---
 commit-graph.c                             |  2 +-
 t/t5329-no-lazy-fetch-with-commit-graph.sh | 47 ++++++++++++++++++++++
 2 files changed, 48 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..4d25d2c950
--- /dev/null
+++ b/t/t5329-no-lazy-fetch-with-commit-graph.sh
@@ -0,0 +1,47 @@
+#!/bin/sh
+
+test_description='test for no lazy fetch with the commit-graph'
+
+. ./test-lib.sh
+
+test_expect_success 'setup: prepare a repository with a commit' '
+	git init with-commit &&
+	test_commit -C with-commit the-commit &&
+	oid=$(git -C with-commit rev-parse HEAD)
+'
+
+test_expect_success 'setup: prepare a repository with commit-graph contains the commit' '
+	git init with-commit-graph &&
+	echo "$(pwd)/with-commit/.git/objects" \
+		>with-commit-graph/.git/objects/info/alternates &&
+	# create a ref that points to the commit in alternates
+	git -C with-commit-graph update-ref refs/ref_to_the_commit "$oid" &&
+	# prepare some other objects to commit-graph
+	test_commit -C with-commit-graph somthing &&
+	git -c gc.writeCommitGraph=true -C with-commit-graph gc &&
+	test_path_is_file with-commit-graph/.git/objects/info/commit-graph
+'
+
+test_expect_success 'setup: change the alternates to what without the commit' '
+	git init --bare without-commit &&
+	echo "$(pwd)/without-commit/objects" \
+		>with-commit-graph/.git/objects/info/alternates &&
+	test_must_fail git -C with-commit-graph cat-file -e $oid
+'
+
+test_expect_success 'setup: prepare another commit to fetch' '
+	test_commit -C with-commit another-commit &&
+	anycommit=$(git -C with-commit rev-parse HEAD)
+'
+
+test_expect_success ULIMIT_PROCESSES 'fetch any commit from promisor with the usage of the commit graph' '
+	git -C with-commit-graph remote add origin "$(pwd)/with-commit" &&
+	git -C with-commit-graph config remote.origin.promisor true &&
+	git -C with-commit-graph config remote.origin.partialclonefilter blob:none &&
+	GIT_TRACE="$(pwd)/trace" run_with_limited_processses \
+		git -C with-commit-graph fetch origin $anycommit 2>err &&
+	test_i18ngrep ! "fatal: promisor-remote: unable to fork off fetch subprocess" err &&
+	test $(grep "fetch origin" trace | wc -l) -eq 1
+'
+
+test_done
-- 
2.36.1
Previous: Junio C HamanoNext: Junio C Hamano
Message 18 of 50 in “Re: An endless loop fetching issue with partial clone, alternates and commit graph”
  1. Haiyng TanJun 14, 2022
  2. Taylor BlauJun 15, 2022
  3. 0/2 Re: An endless loop fetching issue with partial clone, alternates and commit graphHan Xin, Jun 16, 2022
  4. 1/2 commit-graph.c: add "flags" to lookup_commit_in_graph()Han Xin, Jun 16, 2022
  5. 2/2 fetch-pack.c: pass "oi_flags" to lookup_commit_in_graph()Han Xin, Jun 16, 2022
  6. Jonathan TanJun 17, 2022
  7. commit-graph.c: no lazy fetch in lookup_commit_in_graph()Han Xin, Jun 18, 2022
  8. Patrick SteinhardtJun 20, 2022
  9. 欣韩Jun 20, 2022
  10. Patrick SteinhardtJun 20, 2022
  11. Jonathan TanJun 21, 2022
  12. Han XinJun 22, 2022
  13. 0/2 commit-graph.c: no lazy fetch in lookup_commit_in_graph()Han Xin, Jun 24, 2022
  14. 1/2 test-lib.sh: add limited processes to test-libHan Xin, Jun 24, 2022
  15. Junio C HamanoJun 24, 2022
  16. Han XinJun 25, 2022
  17. Junio C HamanoJun 27, 2022
  18. 2/2 commit-graph.c: no lazy fetch in lookup_commit_in_graph()Han Xin, Jun 24, 2022
  19. Junio C HamanoJun 24, 2022
  20. Han XinJun 25, 2022
  21. Han XinJun 25, 2022
  22. 0/2 no lazy fetch in lookup_commit_in_graph()Han Xin, Jun 28, 2022
  23. 1/2 test-lib.sh: add limited processes to test-libHan Xin, Jun 28, 2022
  24. 2/2 commit-graph.c: no lazy fetch in lookup_commit_in_graph()Han Xin, Jun 28, 2022
  25. Ævar Arnfjörð BjarmasonJun 28, 2022
  26. Junio C HamanoJun 28, 2022
  27. Johannes SchindelinJun 30, 2022
  28. Ævar Arnfjörð BjarmasonJun 30, 2022
  29. Junio C HamanoJun 30, 2022
  30. Ævar Arnfjörð BjarmasonJun 30, 2022
  31. Johannes SchindelinJul 1, 2022
  32. Junio C HamanoJul 1, 2022
  33. Han XinJun 29, 2022
  34. test name conflict + js/ci-github-workflow-markup regression (was: [PATCH v3 0/2] no lazy fetch in lookup_commit_in_graph())Ævar Arnfjörð Bjarmason, Jun 30, 2022
  35. 0/1 no lazy fetch in lookup_commit_in_graph()Han Xin, Jul 1, 2022
  36. 1/1 commit-graph.c: no lazy fetch in lookup_commit_in_graph()Han Xin, Jul 1, 2022
  37. Michael J GruberJul 9, 2022
  38. Jeff KingJul 11, 2022
  39. Junio C HamanoJul 11, 2022
  40. Han XinJul 12, 2022
  41. Junio C HamanoJul 12, 2022
  42. Han XinJul 12, 2022
  43. Jeff KingJul 12, 2022
  44. Junio C HamanoJul 12, 2022
  45. 0/1 no lazy fetch in lookup_commit_in_graph()Han Xin, Jul 12, 2022
  46. 1/1 commit-graph.c: no lazy fetch in lookup_commit_in_graph()Han Xin, Jul 12, 2022
  47. Ævar Arnfjörð BjarmasonJul 12, 2022
  48. Han XinJul 13, 2022
  49. Jeff KingJul 12, 2022
  50. t5330: remove run_with_limited_processses()Han Xin, Jul 12, 2022

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