+ if (!read_ref(pathname, sha1)) {
+ /* Must be unique; i.e. when heads/foo and
+ * tags/foo are both present, reject "foo".
+ * Note that read_ref() eventually calls
+ * get_sha1_hex() which can smudge initial
+ * part of the buffer even if what is read
+ * is found to be invalid halfway.
+ */
+ if (1 < found++)
+ return -1;
+ }