X-Git-Url: https://git.tokkee.org/?a=blobdiff_plain;f=builtin-checkout.c;h=793542eb062e7a17ac7bf9331c578ab4dff00aab;hb=e3d42c4773bccebb50f01b108d20b06c6a11e615;hp=64f3a11ae1d415c466def8eccefe9dbc5b6b3926;hpb=a24a32ddb30c904d244fe911f4d9e7e3924fdac7;p=git.git

diff --git a/builtin-checkout.c b/builtin-checkout.c
index 64f3a11ae..793542eb0 100644
--- a/builtin-checkout.c
+++ b/builtin-checkout.c
@@ -397,7 +397,7 @@ static int merge_working_tree(struct checkout_opts *opts,
 		topts.initial_checkout = is_cache_unborn();
 		topts.update = 1;
 		topts.merge = 1;
-		topts.gently = opts->merge;
+		topts.gently = opts->merge && old->commit;
 		topts.verbose_update = !opts->quiet;
 		topts.fn = twoway_merge;
 		topts.dir = xcalloc(1, sizeof(*topts.dir));
@@ -422,7 +422,13 @@ static int merge_working_tree(struct checkout_opts *opts,
 			struct merge_options o;
 			if (!opts->merge)
 				return 1;
-			parse_commit(old->commit);
+
+			/*
+			 * Without old->commit, the below is the same as
+			 * the two-tree unpack we already tried and failed.
+			 */
+			if (!old->commit)
+				return 1;
 
 			/* Do more real merge */
 
@@ -690,7 +696,10 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 	 * case 3: git checkout <something> [<paths>]
 	 *
 	 *   With no paths, if <something> is a commit, that is to
-	 *   switch to the branch or detach HEAD at it.
+	 *   switch to the branch or detach HEAD at it.  As a special case,
+	 *   if <something> is A...B (missing A or B means HEAD but you can
+	 *   omit at most one side), and if there is a unique merge base
+	 *   between A and B, A...B names that merge base.
 	 *
 	 *   With no paths, if <something> is _not_ a commit, no -t nor -b
 	 *   was given, and there is a tracking branch whose name is
@@ -716,7 +725,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 		if (!strcmp(arg, "-"))
 			arg = "@{-1}";
 
-		if (get_sha1(arg, rev)) {
+		if (get_sha1_mb(arg, rev)) {
 			if (has_dash_dash)          /* case (1) */
 				die("invalid reference: %s", arg);
 			if (!patch_mode &&