Re: [PATCH 00/12] Integrate commit-graph into fsck, gc, and fetch

["Martin Ågren" <martin.agren@gmail.com>]

On 10 May 2018 at 21:22, Stefan Beller <sbeller@google.com> wrote:
> On Thu, May 10, 2018 at 12:05 PM, Martin Ågren <martin.agren@gmail.com> wrote:

>> I hope to find time to do some more hands-on testing of this to see that
>> errors actually do get caught.

> Packfiles and loose objects are primary data, which means that those
> need a more advanced way to diagnose and repair them, so I would imagine
> the commit graph fsck is closer to bitmaps fsck, which I would have suspected
> to be found in t5310, but a quick read doesn't reveal many tests that are
> checking for integrity. So I guess the test coverage here is ok, (although we
> should always ask for more)

Since I'm wrapping up for today, I'm posting some simple tests that I
assembled. The last of these showcases one or two problems with the
current error-reporting. Depending on the error, there can be *lots* of
errors reported and there are no new-lines, so the result on stdout can
be a wall of not-very-legible text.

Some of these might not make sense. I just started going through the
documentation on the format, causing some sort of corruption in each
field. Maybe this can be helpful somehow.

Martin

diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
index 82f95eb11f..a7e48db2de 100755
--- a/t/t5318-commit-graph.sh
+++ b/t/t5318-commit-graph.sh
@@ -255,4 +255,49 @@ test_expect_success 'git fsck (checks commit-graph)' '
 	git fsck
 '
 
+# usage: corrupt_data <file> <pos> [<data>]
+corrupt_data() {
+	file=$1
+	pos=$2
+	data="${3:-\0}"
+	printf "$data" | dd of="$file" bs=1 seek="$pos" conv=notrunc
+}
+
+test_expect_success 'detect bad signature' '
+	cd "$TRASH_DIRECTORY/full" &&
+	cp $objdir/info/commit-graph commit-graph-backup &&
+	test_when_finished mv commit-graph-backup $objdir/info/commit-graph &&
+	corrupt_data $objdir/info/commit-graph 0 "\0" &&
+	test_must_fail git commit-graph verify 2>err &&
+	grep "graph signature" err
+'
+
+test_expect_success 'detect bad version number' '
+	cd "$TRASH_DIRECTORY/full" &&
+	cp $objdir/info/commit-graph commit-graph-backup &&
+	test_when_finished mv commit-graph-backup $objdir/info/commit-graph &&
+	corrupt_data $objdir/info/commit-graph 4 "\02" &&
+	test_must_fail git commit-graph verify 2>err &&
+	grep "graph version" err
+'
+
+test_expect_success 'detect bad hash version' '
+	cd "$TRASH_DIRECTORY/full" &&
+	cp $objdir/info/commit-graph commit-graph-backup &&
+	test_when_finished mv commit-graph-backup $objdir/info/commit-graph &&
+	corrupt_data $objdir/info/commit-graph 5 "\02" &&
+	test_must_fail git commit-graph verify 2>err &&
+	grep "hash version" err
+'
+
+test_expect_success 'detect too small chunk-count' '
+	cd "$TRASH_DIRECTORY/full" &&
+	cp $objdir/info/commit-graph commit-graph-backup &&
+	test_when_finished mv commit-graph-backup $objdir/info/commit-graph &&
+	corrupt_data $objdir/info/commit-graph 6 "\01" &&
+	test_must_fail git commit-graph verify 2>err &&
+	cat err
+'
+
+
 test_done
-- 
2.17.0