[PATCH 3/7] commit-graph: read `CDAT` chunk with `pair_chunk_expect()`

[Taylor Blau <me@ttaylorr.com>]

The `CDAT` chunk can benefit from the new chunk-format API function
described in the previous commit. Convert it to `pair_chunk_expect()`
accordingly.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
---
 commit-graph.c          | 15 +++------------
 t/t5318-commit-graph.sh |  3 +--
 2 files changed, 4 insertions(+), 14 deletions(-)

diff --git a/commit-graph.c b/commit-graph.c
index 6072c2a17f..67ab0f2448 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -299,16 +299,6 @@ static int graph_read_oid_fanout(const unsigned char *chunk_start,
 	return 0;
 }
 
-static int graph_read_commit_data(const unsigned char *chunk_start,
-				  size_t chunk_size, void *data)
-{
-	struct commit_graph *g = data;
-	if (chunk_size / GRAPH_DATA_WIDTH != g->num_commits)
-		return error(_("commit-graph commit data chunk is wrong size"));
-	g->chunk_commit_data = chunk_start;
-	return 0;
-}
-
 static int graph_read_generation_data(const unsigned char *chunk_start,
 				      size_t chunk_size, void *data)
 {
@@ -431,8 +421,9 @@ struct commit_graph *parse_commit_graph(struct repo_settings *s,
 		error(_("commit-graph OID lookup chunk is the wrong size"));
 		goto free_and_return;
 	}
-	if (read_chunk(cf, GRAPH_CHUNKID_DATA, graph_read_commit_data, graph)) {
-		error(_("commit-graph required commit data chunk missing or corrupted"));
+	if (pair_chunk_expect(cf, GRAPH_CHUNKID_DATA, &graph->chunk_commit_data,
+			      GRAPH_DATA_WIDTH, graph->num_commits)) {
+		error(_("commit-graph commit data chunk is wrong size"));
 		goto free_and_return;
 	}
 
diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
index b3e8af018d..fd5165bd07 100755
--- a/t/t5318-commit-graph.sh
+++ b/t/t5318-commit-graph.sh
@@ -550,7 +550,7 @@ test_expect_success 'detect missing OID lookup chunk' '
 
 test_expect_success 'detect missing commit data chunk' '
 	corrupt_graph_and_verify $GRAPH_BYTE_COMMIT_DATA_ID "\0" \
-		"commit-graph required commit data chunk missing or corrupted"
+		"commit-graph commit data chunk is wrong size"
 '
 
 test_expect_success 'detect incorrect fanout' '
@@ -875,7 +875,6 @@ test_expect_success 'reader notices too-small commit data chunk' '
 	check_corrupt_chunk CDAT clear 00000000 &&
 	cat >expect.err <<-\EOF &&
 	error: commit-graph commit data chunk is wrong size
-	error: commit-graph required commit data chunk missing or corrupted
 	EOF
 	test_cmp expect.err err
 '
-- 
2.43.0.rc0.39.g44bd344727