commit: force commit to parse from object database

In anticipation of verifying commit-graph file contents against the
object database, create parse_commit_internal() to allow side-stepping
the commit-graph file and parse directly from the object database.

Due to the use of generation numbers, this method should not be called
unless the intention is explicit in avoiding commits from the
commit-graph file.

Signed-off-by: Derrick Stolee <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: derrickstolee

commit.c

@@ -418,7 +418,7 @@ int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long s
 	return 0;
 }
 
-int parse_commit_gently(struct commit *item, int quiet_on_missing)
+int parse_commit_internal(struct commit *item, int quiet_on_missing, int use_commit_graph)
 {
 	enum object_type type;
 	void *buffer;
@@ -429,7 +429,7 @@ int parse_commit_gently(struct commit *item, int quiet_on_missing)
 		return -1;
 	if (item->object.parsed)
 		return 0;
-	if (parse_commit_in_graph(item))
+	if (use_commit_graph && parse_commit_in_graph(item))
 		return 0;
 	buffer = read_object_file(&item->object.oid, &type, &size);
 	if (!buffer)
@@ -441,6 +441,7 @@ int parse_commit_gently(struct commit *item, int quiet_on_missing)
 		return error("Object %s not a commit",
 			     oid_to_hex(&item->object.oid));
 	}
+
 	ret = parse_commit_buffer(item, buffer, size, 0);
 	if (save_commit_buffer && !ret) {
 		set_commit_buffer(item, buffer, size);
@@ -450,6 +451,11 @@ int parse_commit_gently(struct commit *item, int quiet_on_missing)
 	return ret;
 }
 
+int parse_commit_gently(struct commit *item, int quiet_on_missing)
+{
+	return parse_commit_internal(item, quiet_on_missing, 1);
+}
+
 void parse_commit_or_die(struct commit *item)
 {
 	if (parse_commit(item))

commit.h

@@ -77,6 +77,7 @@ struct commit *lookup_commit_reference_by_name(const char *name);
 struct commit *lookup_commit_or_die(const struct object_id *oid, const char *ref_name);
 
 int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size, int check_graph);
+int parse_commit_internal(struct commit *item, int quiet_on_missing, int use_commit_graph);
 int parse_commit_gently(struct commit *item, int quiet_on_missing);
 static inline int parse_commit(struct commit *item)
 {