submodule: Add --force option for git submodule update

diff --git a/branch.c b/branch.c
index 2ab42aaf4da38b4ea45ef7f0a0f6b807313d4a22..da5c03e56545b79cb92dd850ed09e81c21f9162f 100644 (file)
--- a/branch.c
+++ b/branch.c
@@ -159,7 +159,7 @@ void create_branch(const char *head,
                        dont_change_ref = 1;
                else if (!force)
                        die("A branch named '%s' already exists.", name);
-               else if (!is_bare_repository() && !strcmp(head, name))
+               else if (!is_bare_repository() && head && !strcmp(head, name))
                        die("Cannot force update the current branch.");
                forcing = 1;
        }
@@ -175,9 +175,14 @@ void create_branch(const char *head,
                        die("Cannot setup tracking information; starting point is not a branch.");
                break;
        case 1:
-               /* Unique completion -- good, only if it is a real ref */
-               if (explicit_tracking && !strcmp(real_ref, "HEAD"))
-                       die("Cannot setup tracking information; starting point is not a branch.");
+               /* Unique completion -- good, only if it is a real branch */
+               if (prefixcmp(real_ref, "refs/heads/") &&
+                   prefixcmp(real_ref, "refs/remotes/")) {
+                       if (explicit_tracking)
+                               die("Cannot setup tracking information; starting point is not a branch.");
+                       else
+                               real_ref = NULL;
+               }
                break;
        default:
                die("Ambiguous object name: '%s'.", start_name);