t/t5318-commit-graph.sh: test generation zero transitions during fsck

The second test called "detect incorrect generation number" asserts that
we correctly warn during an fsck when we see a non-zero generation
number after seeing a zero beforehand.

The other transition (going from non-zero to zero) was previously
untested. Test both directions, and rename the existing test to make
clear which direction it is exercising.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
index 4e70820c74eba23ebecc9ba17a57fd909f4a71a1..8e96471b34d960e0becd00cbaab1a0fb98c97edf 100755 (executable)
--- a/t/t5318-commit-graph.sh
+++ b/t/t5318-commit-graph.sh
@@ -450,14 +450,15 @@ GRAPH_BYTE_FANOUT2=$(($GRAPH_FANOUT_OFFSET + 4 * 255))
 GRAPH_OID_LOOKUP_OFFSET=$(($GRAPH_FANOUT_OFFSET + 4 * 256))
 GRAPH_BYTE_OID_LOOKUP_ORDER=$(($GRAPH_OID_LOOKUP_OFFSET + $HASH_LEN * 8))
 GRAPH_BYTE_OID_LOOKUP_MISSING=$(($GRAPH_OID_LOOKUP_OFFSET + $HASH_LEN * 4 + 10))
+GRAPH_COMMIT_DATA_WIDTH=$(($HASH_LEN + 16))
 GRAPH_COMMIT_DATA_OFFSET=$(($GRAPH_OID_LOOKUP_OFFSET + $HASH_LEN * $NUM_COMMITS))
 GRAPH_BYTE_COMMIT_TREE=$GRAPH_COMMIT_DATA_OFFSET
 GRAPH_BYTE_COMMIT_PARENT=$(($GRAPH_COMMIT_DATA_OFFSET + $HASH_LEN))
 GRAPH_BYTE_COMMIT_EXTRA_PARENT=$(($GRAPH_COMMIT_DATA_OFFSET + $HASH_LEN + 4))
 GRAPH_BYTE_COMMIT_WRONG_PARENT=$(($GRAPH_COMMIT_DATA_OFFSET + $HASH_LEN + 3))
 GRAPH_BYTE_COMMIT_GENERATION=$(($GRAPH_COMMIT_DATA_OFFSET + $HASH_LEN + 11))
+GRAPH_BYTE_COMMIT_GENERATION_LAST=$(($GRAPH_BYTE_COMMIT_GENERATION + $(($NUM_COMMITS - 1)) * $GRAPH_COMMIT_DATA_WIDTH))
 GRAPH_BYTE_COMMIT_DATE=$(($GRAPH_COMMIT_DATA_OFFSET + $HASH_LEN + 12))
-GRAPH_COMMIT_DATA_WIDTH=$(($HASH_LEN + 16))
 GRAPH_OCTOPUS_DATA_OFFSET=$(($GRAPH_COMMIT_DATA_OFFSET + \
                             $GRAPH_COMMIT_DATA_WIDTH * $NUM_COMMITS))
 GRAPH_BYTE_OCTOPUS=$(($GRAPH_OCTOPUS_DATA_OFFSET + 4))
@@ -596,11 +597,6 @@ test_expect_success 'detect incorrect generation number' '
                "generation for commit"
 '
 
-test_expect_success 'detect incorrect generation number' '
-       corrupt_graph_and_verify $GRAPH_BYTE_COMMIT_GENERATION "\01" \
-               "but zero elsewhere"
-'
-
 test_expect_success 'detect incorrect commit date' '
        corrupt_graph_and_verify $GRAPH_BYTE_COMMIT_DATE "\01" \
                "commit date"
@@ -622,6 +618,16 @@ test_expect_success 'detect incorrect chunk count' '
                $GRAPH_CHUNK_LOOKUP_OFFSET
 '
 
+test_expect_success 'detect mixed generation numbers (non-zero to zero)' '
+       corrupt_graph_and_verify $GRAPH_BYTE_COMMIT_GENERATION_LAST "\0\0\0\0" \
+               "but non-zero elsewhere"
+'
+
+test_expect_success 'detect mixed generation numbers (zero to non-zero)' '
+       corrupt_graph_and_verify $GRAPH_BYTE_COMMIT_GENERATION "\0\0\0\0" \
+               "but zero elsewhere"
+'
+
 test_expect_success 'git fsck (checks commit-graph when config set to true)' '
        git -C full fsck &&
        corrupt_graph_and_verify $GRAPH_BYTE_FOOTER "\00" \