builtin/clone: initialize hash algorithm properly

bk2204 · gitster · commit b65dc2cebd6a · 2020-05-27T10:07:06.000-07:00
When performing a clone, we don't know what hash algorithm the other end
will support.  Currently, we don't support fetching data belonging to a
different algorithm, so we must know what algorithm the remote side is
using in order to properly initialize the repository.  We can know that
only after fetching the refs, so if the remote side has any references,
use that information to reinitialize the repository with the correct
hash algorithm information.

Signed-off-by: brian m. carlson &lt;sandals@crustytoothpaste.net&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
diff --git a/builtin/clone.c b/builtin/clone.c
@@ -1217,6 +1217,15 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	refs = transport_get_remote_refs(transport, &ref_prefixes);
 
 	if (refs) {
+		int hash_algo = hash_algo_by_ptr(transport_get_hash_algo(transport));
+
+		/*
+		 * Now that we know what algorithm the remote side is using,
+		 * let's set ours to the same thing.
+		 */
+		initialize_repository_version(hash_algo);
+		repo_set_hash_algo(the_repository, hash_algo);
+
 		mapped_refs = wanted_peer_refs(refs, &remote->fetch);
 		/*
 		 * transport_get_remote_refs() may return refs with null sha-1
