if ( $namespaces === null || $rebuild ) {
global $wgExtraNamespaces, $wgCanonicalNamespaceNames;
$namespaces = array( NS_MAIN => '' ) + $wgCanonicalNamespaceNames;
if ( $namespaces === null || $rebuild ) {
global $wgExtraNamespaces, $wgCanonicalNamespaceNames;
$namespaces = array( NS_MAIN => '' ) + $wgCanonicalNamespaceNames;