+ /*
+ * Value is "refs/foo/bar/<asterisk>:refs/baz/boa/<asterisk>"
+ * and start_ref begins with "refs/baz/boa/"; the name at the
+ * remote is refs/foo/bar/ with the remaining part of the
+ * start_ref. The length of the prefix on the RHS is (end -
+ * colon - 2), including the slash immediately before the
+ * asterisk.
+ */
+ if ((strlen(start_ref) < end - colon - 2) ||
+ memcmp(start_ref, colon + 1, end - colon - 2))
+ return 0; /* does not match prefix */
+
+ /* Replace the asterisk with the remote branch name. */
+ nfasprintf(&config_repo, "%.*s%s",
+ (colon - 1) - value, value,
+ start_ref + (end - colon - 2));
+ return 1;