[PATCH v3 11/20] commit-graph: verify root tree OIDs

[Derrick Stolee]

The 'verify' subcommand must compare the commit content parsed from the
commit-graph and compare it against the content in the object database.
Use lookup_commit() and parse_commit_in_graph_one() to parse the commits
from the graph and compare against a commit that is loaded separately
and parsed directly from the object database.

Add checks for the root tree OID.

Signed-off-by: Derrick Stolee <dsto...@microsoft.com>
---
 commit-graph.c          | 17 ++++++++++++++++-
 t/t5318-commit-graph.sh |  7 +++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/commit-graph.c b/commit-graph.c
index 0420ebcd87..19ea369fc6 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -880,6 +880,8 @@ int verify_commit_graph(struct commit_graph *g)
                return verify_commit_graph_error;
 
        for (i = 0; i < g->num_commits; i++) {
+               struct commit *graph_commit;
+
                hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
 
                if (i && oidcmp(&prev_oid, &cur_oid) >= 0)
@@ -897,6 +899,11 @@ int verify_commit_graph(struct commit_graph *g)
 
                        cur_fanout_pos++;
                }
+
+               graph_commit = lookup_commit(&cur_oid);
+               if (!parse_commit_in_graph_one(g, graph_commit))
+                       graph_report("failed to parse %s from commit-graph",
+                                    oid_to_hex(&cur_oid));
        }
 
        while (cur_fanout_pos < 256) {
@@ -913,16 +920,24 @@ int verify_commit_graph(struct commit_graph *g)
                return verify_commit_graph_error;
 
        for (i = 0; i < g->num_commits; i++) {
-               struct commit *odb_commit;
+               struct commit *graph_commit, *odb_commit;
 
                hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
 
+               graph_commit = lookup_commit(&cur_oid);
                odb_commit = (struct commit *)create_object(cur_oid.hash, 
alloc_commit_node());
                if (parse_commit_internal(odb_commit, 0, 0)) {
                        graph_report("failed to parse %s from object database",
                                     oid_to_hex(&cur_oid));
                        continue;
                }
+
+               if (oidcmp(&get_commit_tree_in_graph_one(g, 
graph_commit)->object.oid,
+                          get_commit_tree_oid(odb_commit)))
+                       graph_report("root tree OID for commit %s in 
commit-graph is %s != %s",
+                                    oid_to_hex(&cur_oid),
+                                    
oid_to_hex(get_commit_tree_oid(graph_commit)),
+                                    
oid_to_hex(get_commit_tree_oid(odb_commit)));
        }
 
        return verify_commit_graph_error;
diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
index 996a016239..21cc8e82f3 100755
--- a/t/t5318-commit-graph.sh
+++ b/t/t5318-commit-graph.sh
@@ -267,6 +267,8 @@ GRAPH_BYTE_FANOUT2=`expr $GRAPH_FANOUT_OFFSET + 4 \* 255`
 GRAPH_OID_LOOKUP_OFFSET=`expr $GRAPH_FANOUT_OFFSET + 4 \* 256`
 GRAPH_BYTE_OID_LOOKUP_ORDER=`expr $GRAPH_OID_LOOKUP_OFFSET + $HASH_LEN \* 8`
 GRAPH_BYTE_OID_LOOKUP_MISSING=`expr $GRAPH_OID_LOOKUP_OFFSET + $HASH_LEN \* 4 
+ 10`
+GRAPH_COMMIT_DATA_OFFSET=`expr $GRAPH_OID_LOOKUP_OFFSET + $HASH_LEN \* 
$NUM_COMMITS`
+GRAPH_BYTE_COMMIT_TREE=$GRAPH_COMMIT_DATA_OFFSET
 
 # usage: corrupt_graph_and_verify <position> <data> <string>
 # Manipulates the commit-graph file at the position
@@ -341,4 +343,9 @@ test_expect_success 'detect OID not in object database' '
                "from object database"
 '
 
+test_expect_success 'detect incorrect tree OID' '
+       corrupt_graph_and_verify $GRAPH_BYTE_COMMIT_TREE "\01" \
+               "root tree OID for commit"
+'
+
 test_done
-- 
2.16.2.329.gfb62395de6