branch: avoid unnecessary worktrees traversals

When we rename a branch ref, we need to update any worktree that have
its HEAD pointing to the branch ref being renamed, so to make it use the
new ref name.

If we know in advance that we're renaming a branch that is not currently
checked out in any worktree, we can skip this step entirely.  Let's do
it so.

Signed-off-by: Rubén Justo <rjusto@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/branch.c b/builtin/branch.c
index a93b9fc0abe3274796ca191f51e5bf7a3a348c11..6a564b22b0b5c4dd2a18f504007183e497f2cf8c 100644 (file)
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -617,7 +617,7 @@ static void copy_or_rename_branch(const char *oldname, const char *newname, int
                                interpreted_oldname);
        }
 
-       if (!copy &&
+       if (!copy && (oldref_usage & IS_HEAD) &&
            replace_each_worktree_head_symref(worktrees, oldref.buf, newref.buf,
                                              logmsg.buf))
                die(_("Branch renamed to %s, but HEAD is not updated!"), newname);