branch: don't assume the merge filter ref exists

diff --git a/builtin/branch.c b/builtin/branch.c
index 009b7138ac72c5845225ce1f801be908ede4e3b4..d6691af0a57f3ced2fc943e8a036ac1e03cb0566 100644 (file)
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -528,6 +528,10 @@ static int print_ref_list(int kinds, int detached, int verbose, int abbrev, stru
        if (merge_filter != NO_FILTER) {
                struct commit *filter;
                filter = lookup_commit_reference_gently(merge_filter_ref, 0);
+               if (!filter)
+                       die("object '%s' does not point to a commit",
+                           sha1_to_hex(merge_filter_ref));
+
                filter->object.flags |= UNINTERESTING;
                add_pending_object(&ref_list.revs,
                                   (struct object *) filter, "");
@@ -568,6 +572,7 @@ static void rename_branch(const char *oldname, const char *newname, int force)
        unsigned char sha1[20];
        struct strbuf oldsection = STRBUF_INIT, newsection = STRBUF_INIT;
        int recovery = 0;
+       int clobber_head_ok;
 
        if (!oldname)
                die(_("cannot rename the current branch while not on any."));
@@ -583,7 +588,13 @@ static void rename_branch(const char *oldname, const char *newname, int force)
                        die(_("Invalid branch name: '%s'"), oldname);
        }
 
-       validate_new_branchname(newname, &newref, force, 0);
+       /*
+        * A command like "git branch -M currentbranch currentbranch" cannot
+        * cause the worktree to become inconsistent with HEAD, so allow it.
+        */
+       clobber_head_ok = !strcmp(oldname, newname);
+
+       validate_new_branchname(newname, &newref, force, clobber_head_ok);
 
        strbuf_addf(&logmsg, "Branch: renamed %s to %s",
                 oldref.buf, newref.buf);
@@ -705,7 +716,7 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
        argc = parse_options(argc, argv, prefix, options, builtin_branch_usage,
                             0);
 
-       if (!delete && !rename && !force_create && argc == 0)
+       if (!delete && !rename && argc == 0)
                list = 1;
 
        if (!!delete + !!rename + !!force_create + !!list > 1)
@@ -719,15 +730,18 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
        else if (list)
                return print_ref_list(kinds, detached, verbose, abbrev,
                                      with_commit, argv);
-       else if (rename && (argc == 1))
-               rename_branch(head, argv[0], rename > 1);
-       else if (rename && (argc == 2))
-               rename_branch(argv[0], argv[1], rename > 1);
-       else if (argc <= 2) {
+       else if (rename) {
+               if (argc == 1)
+                       rename_branch(head, argv[0], rename > 1);
+               else if (argc == 2)
+                       rename_branch(argv[0], argv[1], rename > 1);
+               else
+                       usage_with_options(builtin_branch_usage, options);
+       } else if (argc > 0 && argc <= 2) {
                if (kinds != REF_LOCAL_BRANCH)
                        die(_("-a and -r options to 'git branch' do not make sense with a branch name"));
                create_branch(head, argv[0], (argc == 2) ? argv[1] : head,
-                             force_create, reflog, track);
+                             force_create, reflog, 0, track);
        } else
                usage_with_options(builtin_branch_usage, options);