+ /**
+ * Helper function to set a value to a specific global, if it isn't set already.
+ *
+ * @param string $key The config key with the prefix and anything
+ * @param mixed $value The value of the config
+ */
+ private function addConfigGlobal( $key, $value ) {
+ if ( array_key_exists( $key, $this->globals ) ) {
+ throw new RuntimeException(
+ "The configuration setting '$key' was already set by another extension,"
+ . " and cannot be set again." );
+ }
+ $this->globals[$key] = $value;
+ }
+