check_ref_format(): tighten refname rules

diff --git a/builtin-branch.c b/builtin-branch.c
index afeed68cfd7482c40a276c00ef3b7bfd09433950..330e0c3f1605b46ab6257f0947051c3e562d9cc6 100644 (file)
--- a/builtin-branch.c
+++ b/builtin-branch.c
@@ -464,12 +464,21 @@ static void rename_branch(const char *oldname, const char *newname, int force)
        struct strbuf oldref = STRBUF_INIT, newref = STRBUF_INIT, logmsg = STRBUF_INIT;
        unsigned char sha1[20];
        struct strbuf oldsection = STRBUF_INIT, newsection = STRBUF_INIT;
+       int recovery = 0;
 
        if (!oldname)
                die("cannot rename the current branch while not on any.");
 
-       if (strbuf_check_branch_ref(&oldref, oldname))
-               die("Invalid branch name: '%s'", oldname);
+       if (strbuf_check_branch_ref(&oldref, oldname)) {
+               /*
+                * Bad name --- this could be an attempt to rename a
+                * ref that we used to allow to be created by accident.
+                */
+               if (resolve_ref(oldref.buf, sha1, 1, NULL))
+                       recovery = 1;
+               else
+                       die("Invalid branch name: '%s'", oldname);
+       }
 
        if (strbuf_check_branch_ref(&newref, newname))
                die("Invalid branch name: '%s'", newname);
@@ -484,6 +493,9 @@ static void rename_branch(const char *oldname, const char *newname, int force)
                die("Branch rename failed");
        strbuf_release(&logmsg);
 
+       if (recovery)
+               warning("Renamed a misnamed branch '%s' away", oldref.buf + 11);
+
        /* no need to pass logmsg here as HEAD didn't really move */
        if (!strcmp(oldname, head) && create_symref("HEAD", newref.buf, NULL))
                die("Branch renamed to %s, but HEAD is not updated!", newname);