commit-graph: verify chains with --shallow mode

If we wrote a commit-graph chain, we only modified the tip file in
the chain. It is valuable to verify what we wrote, but not waste
time checking files we did not write.

Add a '--shallow' option to the 'git commit-graph verify' subcommand
and check that it does not read the base graph in a two-file chain.

Making the verify subcommand read from a chain of commit-graphs takes
some rearranging of the builtin code.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 62 insertions, 0 deletions

diff --git a/t/t5324-split-commit-graph.sh b/t/t5324-split-commit-graph.sh
index 1b699a543c..3df90ae58f 100755
--- a/t/t5324-split-commit-graph.sh
+++ b/t/t5324-split-commit-graph.sh
@@ -216,4 +216,66 @@ test_expect_success 'test merge stragety constants' '
 	)
 '
 
+corrupt_file() {
+	file=$1
+	pos=$2
+	data="${3:-\0}"
+	printf "$data" | dd of="$file" bs=1 seek="$pos" conv=notrunc
+}
+
+test_expect_success 'verify hashes along chain, even in shallow' '
+	git clone --no-hardlinks . verify &&
+	(
+		cd verify &&
+		git commit-graph verify &&
+		base_file=$graphdir/graph-$(head -n 1 $graphdir/commit-graph-chain).graph &&
+		corrupt_file "$base_file" 1760 "\01" &&
+		test_must_fail git commit-graph verify --shallow 2>test_err &&
+		grep -v "^+" test_err >err &&
+		test_i18ngrep "incorrect checksum" err
+	)
+'
+
+test_expect_success 'verify --shallow does not check base contents' '
+	git clone --no-hardlinks . verify-shallow &&
+	(
+		cd verify-shallow &&
+		git commit-graph verify &&
+		base_file=$graphdir/graph-$(head -n 1 $graphdir/commit-graph-chain).graph &&
+		corrupt_file "$base_file" 1000 "\01" &&
+		git commit-graph verify --shallow &&
+		test_must_fail git commit-graph verify 2>test_err &&
+		grep -v "^+" test_err >err &&
+		test_i18ngrep "incorrect checksum" err
+	)
+'
+
+test_expect_success 'warn on base graph chunk incorrect' '
+	git clone --no-hardlinks . base-chunk &&
+	(
+		cd base-chunk &&
+		git commit-graph verify &&
+		base_file=$graphdir/graph-$(tail -n 1 $graphdir/commit-graph-chain).graph &&
+		corrupt_file "$base_file" 1376 "\01" &&
+		git commit-graph verify --shallow 2>test_err &&
+		grep -v "^+" test_err >err &&
+		test_i18ngrep "commit-graph chain does not match" err
+	)
+'
+
+test_expect_success 'verify after commit-graph-chain corruption' '
+	git clone --no-hardlinks . verify-chain &&
+	(
+		cd verify-chain &&
+		corrupt_file "$graphdir/commit-graph-chain" 60 "G" &&
+		git commit-graph verify 2>test_err &&
+		grep -v "^+" test_err >err &&
+		test_i18ngrep "invalid commit-graph chain" err &&
+		corrupt_file "$graphdir/commit-graph-chain" 60 "A" &&
+		git commit-graph verify 2>test_err &&
+		grep -v "^+" test_err >err &&
+		test_i18ngrep "unable to find all commit-graph files" err
+	)
+'
+
 test_done