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[PATCH 6/6] commit-graph: report incomplete chains during verification

From
Jeff King <peff@peff.net>
Date
Sep 26, 2023, 06:04 UTC
Message-ID
<20230926060430.GF1341418@coredump.intra.peff.net>
In-Reply-To
<20230926055452.GA1341109@coredump.intra.peff.net>

The load_commit_graph_chain_fd_st() function will stop loading chains when it sees an error. But if it has loaded any graph slice at all, it will return it. This is a good thing for normal use (we use what data we can, and this is just an optimization). But it's a bad thing for "commit-graph verify", which should be careful about finding any irregularities. We do complain to stderr with a warning(), but the verify command still exits with a successful return code.

The new tests here cover corruption of both the base and tip slices of the chain. The corruption of the base file already works (it is the first file we look at, so when we see the error we return NULL). The "tip" case is what is fixed by this patch (it complains to stderr but still returns the base slice).

Note that this also causes us to adjust a test later in the file that similarly corrupts a tip (though confusingly the test script calls this "base"). It checks stderr but erroneously expects the whole "verify" command to exit with a successful code.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/commit-graph.c        | 10 +++++++++-
 commit-graph.c                |  9 +++++++--
 commit-graph.h                |  3 ++-
 t/t5324-split-commit-graph.sh | 28 +++++++++++++++++++++++++++-
 4 files changed, 45 insertions(+), 5 deletions(-)
diff --git a/builtin/commit-graph.c b/builtin/commit-graph.c
index 50c15d9bfe..f5e66e9969 100644
--- a/builtin/commit-graph.c
+++ b/builtin/commit-graph.c
@@ -74,6 +74,7 @@ static int graph_verify(int argc, const char **argv, const char *prefix)
 	int fd;
 	struct stat st;
 	int flags = 0;
+	int incomplete_chain = 0;
 	int ret;
 
 	static struct option builtin_commit_graph_verify_options[] = {
@@ -122,13 +123,20 @@ static int graph_verify(int argc, const char **argv, const char *prefix)
 	else if (opened == OPENED_GRAPH)
 		graph = load_commit_graph_one_fd_st(the_repository, fd, &st, odb);
 	else
-		graph = load_commit_graph_chain_fd_st(the_repository, fd, &st);
+		graph = load_commit_graph_chain_fd_st(the_repository, fd, &st,
+						      &incomplete_chain);
 
 	if (!graph)
 		return 1;
 
 	ret = verify_commit_graph(the_repository, graph, flags);
 	free_commit_graph(graph);
+
+	if (incomplete_chain) {
+		error("one or more commit-graph chain files could not be loaded");
+		ret |= 1;
+	}
+
 	return ret;
 }
 
diff --git a/commit-graph.c b/commit-graph.c
index b1d3e5bf94..148af50058 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -563,14 +563,17 @@ int open_commit_graph_chain(const char *chain_file,
 }
 
 struct commit_graph *load_commit_graph_chain_fd_st(struct repository *r,
-						   int fd, struct stat *st)
+						   int fd, struct stat *st,
+						   int *incomplete_chain)
 {
 	struct commit_graph *graph_chain = NULL;
 	struct strbuf line = STRBUF_INIT;
 	struct object_id *oids;
 	int i = 0, valid = 1, count;
 	FILE *fp = xfdopen(fd, "r");
 
+	*incomplete_chain = 0;
+
 	count = st->st_size / (the_hash_algo->hexsz + 1);
 	CALLOC_ARRAY(oids, count);
 
@@ -608,6 +611,7 @@ struct commit_graph *load_commit_graph_chain_fd_st(struct repository *r,
 
 		if (!valid) {
 			warning(_("unable to find all commit-graph files"));
+			*incomplete_chain = 1;
 			break;
 		}
 	}
@@ -630,8 +634,9 @@ static struct commit_graph *load_commit_graph_chain(struct repository *r,
 	struct commit_graph *g = NULL;
 
 	if (open_commit_graph_chain(chain_file, &fd, &st)) {
+		int incomplete;
 		/* ownership of fd is taken over by load function */
-		g = load_commit_graph_chain_fd_st(r, fd, &st);
+		g = load_commit_graph_chain_fd_st(r, fd, &st, &incomplete);
 	}
 
 	free(chain_file);
diff --git a/commit-graph.h b/commit-graph.h
index 3b662fd2b5..20ada7e891 100644
--- a/commit-graph.h
+++ b/commit-graph.h
@@ -107,7 +107,8 @@ struct commit_graph *load_commit_graph_one_fd_st(struct repository *r,
 						 int fd, struct stat *st,
 						 struct object_directory *odb);
 struct commit_graph *load_commit_graph_chain_fd_st(struct repository *r,
-						   int fd, struct stat *st);
+						   int fd, struct stat *st,
+						   int *incomplete_chain);
 struct commit_graph *read_commit_graph_one(struct repository *r,
 					   struct object_directory *odb);
 
diff --git a/t/t5324-split-commit-graph.sh b/t/t5324-split-commit-graph.sh
index 86d56debf6..598660557a 100755
--- a/t/t5324-split-commit-graph.sh
+++ b/t/t5324-split-commit-graph.sh
@@ -285,6 +285,32 @@ test_expect_success 'verify hashes along chain, even in shallow' '
 	)
 '
 
+test_expect_success 'verify notices chain slice which is bogus (base)' '
+	git clone --no-hardlinks . verify-chain-bogus-base &&
+	(
+		cd verify-chain-bogus-base &&
+		git commit-graph verify &&
+		base_file=$graphdir/graph-$(sed -n 1p $graphdir/commit-graph-chain).graph &&
+		echo "garbage" >$base_file &&
+		test_must_fail git commit-graph verify 2>test_err &&
+		grep -v "^+" test_err >err &&
+		grep "commit-graph file is too small" err
+	)
+'
+
+test_expect_success 'verify notices chain slice which is bogus (tip)' '
+	git clone --no-hardlinks . verify-chain-bogus-tip &&
+	(
+		cd verify-chain-bogus-tip &&
+		git commit-graph verify &&
+		tip_file=$graphdir/graph-$(sed -n 2p $graphdir/commit-graph-chain).graph &&
+		echo "garbage" >$tip_file &&
+		test_must_fail git commit-graph verify 2>test_err &&
+		grep -v "^+" test_err >err &&
+		grep "commit-graph file is too small" err
+	)
+'
+
 test_expect_success 'verify --shallow does not check base contents' '
 	git clone --no-hardlinks . verify-shallow &&
 	(
@@ -306,7 +332,7 @@ test_expect_success 'warn on base graph chunk incorrect' '
 		git commit-graph verify &&
 		base_file=$graphdir/graph-$(tail -n 1 $graphdir/commit-graph-chain).graph &&
 		corrupt_file "$base_file" $(test_oid base) "\01" &&
-		git commit-graph verify --shallow 2>test_err &&
+		test_must_fail git commit-graph verify --shallow 2>test_err &&
 		grep -v "^+" test_err >err &&
 		test_i18ngrep "commit-graph chain does not match" err
 	)
-- 
2.42.0.758.gd56856b565
Previous: Jeff KingNext: Jeff King
Message 7 of 16 in “some "commit-graph verify" fixes for chains”
  1. 0/6 some "commit-graph verify" fixes for chainsJeff King, Sep 26, 2023
  2. 1/6 commit-graph: factor out chain opening functionJeff King, Sep 26, 2023
  3. 2/6 commit-graph: check mixed generation validation when loading chain fileJeff King, Sep 26, 2023
  4. 3/6 t5324: harmonize sha1/sha256 graph chain corruptionJeff King, Sep 26, 2023
  5. 4/6 commit-graph: detect read errors when verifying graph chainJeff King, Sep 26, 2023
  6. 5/6 commit-graph: tighten chain size checkJeff King, Sep 26, 2023
  7. 6/6 commit-graph: report incomplete chains during verificationJeff King, Sep 26, 2023
  8. Jeff KingSep 28, 2023
  9. 0/6 some "commit-graph verify" fixes for chainsJeff King, Sep 28, 2023
  10. 1/6 commit-graph: factor out chain opening functionJeff King, Sep 28, 2023
  11. 2/6 commit-graph: check mixed generation validation when loading chain fileJeff King, Sep 28, 2023
  12. 3/6 t5324: harmonize sha1/sha256 graph chain corruptionJeff King, Sep 28, 2023
  13. 4/6 commit-graph: detect read errors when verifying graph chainJeff King, Sep 28, 2023
  14. 5/6 commit-graph: tighten chain size checkJeff King, Sep 28, 2023
  15. 6/6 commit-graph: report incomplete chains during verificationJeff King, Sep 28, 2023
  16. Taylor BlauOct 5, 2023

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