[RFC PATCH 12/12] commit-graph: specify OID version for SHA-256

["brian m. carlson" <sandals@crustytoothpaste.net>]

Since the commit-graph code wants to serialize the hash algorithm into
the data store, specify a version number for each supported algorithm.
Note that we don't use the values of the constants themselves, as they
are internal and could change in the future.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 commit-graph.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/commit-graph.c b/commit-graph.c
index 29356d84a2..5b86acdb43 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -45,7 +45,14 @@ char *get_commit_graph_filename(const char *obj_dir)
 
 static uint8_t oid_version(void)
 {
-	return 1;
+	switch (hash_algo_by_ptr(the_hash_algo)) {
+		case GIT_HASH_SHA1:
+			return 1;
+		case GIT_HASH_SHA256:
+			return 2;
+		default:
+			BUG("unknown hash algorithm");
+	}
 }
 
 static struct commit_graph *alloc_commit_graph(void)