branch: allow a no-op "branch -M <current-branch> HEAD"

[git.git] / builtin / branch.c

diff --git a/builtin/branch.c b/builtin/branch.c
index 009b7138ac72c5845225ce1f801be908ede4e3b4..24f33b241eb019d6e75485f8a540d5d8123c36d2 100644 (file)
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -568,6 +568,7 @@ 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 +584,13 @@ 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);
@@ -719,11 +726,14 @@ 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 <= 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,