[PATCH 02/12] commit-graph: verify file header information

[Derrick Stolee]

During a run of 'git commit-graph verify', list the issues with the
header information in the commit-graph file. Some of this information
is inferred from the loaded 'struct commit_graph'. Some header
information is checked as part of load_commit_graph_one().

Signed-off-by: Derrick Stolee <dsto...@microsoft.com>
---
 commit-graph.c | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/commit-graph.c b/commit-graph.c
index b25aaed128..c3b8716c14 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -818,7 +818,28 @@ void write_commit_graph(const char *obj_dir,
        oids.nr = 0;
 }
 
+static int verify_commit_graph_error;
+#define graph_report(...) \
+       do {\
+               verify_commit_graph_error = 1;\
+               printf(__VA_ARGS__);\
+       } while (0);
+
 int verify_commit_graph(struct commit_graph *g)
 {
-       return !g;
+       if (!g) {
+               graph_report(_("no commit-graph file loaded"));
+               return 1;
+       }
+
+       verify_commit_graph_error = 0;
+
+       if (!g->chunk_oid_fanout)
+               graph_report(_("commit-graph is missing the OID Fanout chunk"));
+       if (!g->chunk_oid_lookup)
+               graph_report(_("commit-graph is missing the OID Lookup chunk"));
+       if (!g->chunk_commit_data)
+               graph_report(_("commit-graph is missing the Commit Data 
chunk"));
+
+       return verify_commit_graph_error;
 }
-- 
2.16.2.329.gfb62395de6