merge(3p/git): Merge git subtree at v2.29.2 r/1890

This also bumps the stable nixpkgs to 20.09 as of 2020-11-21, because
there is some breakage in the git build related to the netrc
credentials helper which someone has taken care of in nixpkgs.

The stable channel is not used for anything other than git, so this
should be fine.

Change-Id: I3575a19dab09e1e9556cf8231d717de9890484fb

1 files changed, 1 insertions, 11 deletions

diff --git a/third_party/git/builtin/merge-base.c b/third_party/git/builtin/merge-base.c
index e3f8da13b69b..6719ac198dc2 100644
--- a/third_party/git/builtin/merge-base.c
+++ b/third_party/git/builtin/merge-base.c
@@ -114,26 +114,16 @@ static int handle_is_ancestor(int argc, const char **argv)
 static int handle_fork_point(int argc, const char **argv)
 {
 	struct object_id oid;
-	char *refname;
 	struct commit *derived, *fork_point;
 	const char *commitname;
 
-	switch (dwim_ref(argv[0], strlen(argv[0]), &oid, &refname)) {
-	case 0:
-		die("No such ref: '%s'", argv[0]);
-	case 1:
-		break; /* good */
-	default:
-		die("Ambiguous refname: '%s'", argv[0]);
-	}
-
 	commitname = (argc == 2) ? argv[1] : "HEAD";
 	if (get_oid(commitname, &oid))
 		die("Not a valid object name: '%s'", commitname);
 
 	derived = lookup_commit_reference(the_repository, &oid);
 
-	fork_point = get_fork_point(refname, derived);
+	fork_point = get_fork_point(argv[0], derived);
 
 	if (!fork_point)
 		return 1;