fix router error for /index/nonexistent

router.php

@@ -11,18 +11,25 @@ define('PAGE_ADDRESS', $pageAddress . ((substr($pageAddress, -1) === '/' OR $pag
 define('PAGE_LINEAGE', explode('/', PAGE_ADDRESS));
 define('SERVICE', dirname(PAGE_ADDRESS));
 
+function pageNotFound(): never {
+	http_response_code(404);
+	exit(_('Page not found.'));
+}
 function getPageInformations(array $pages, array $pageElements): array { // Recursively retrieves page metadata from pages.php
-	if (!isset($pages['index']) OR $pageElements[0] === 'index')
+	if (!isset($pages['index']) OR $pageElements[0] === 'index') {
+		if (count($pageElements) !== 1)
+			pageNotFound();
 		return [
-			'titles_lineage' => [$pages[$pageElements[0]]['title'] ?? false],
-			'page_metadata' => $pages[$pageElements[0]] ?? NULL,
+			'titles_lineage' => [$pages[$pageElements[0]]['title'] ?? pageNotFound()],
+			'page_metadata' => $pages[$pageElements[0]],
 			'terminal' => $pageElements[0] !== 'index'
 		];
+	}
 	$result = $pages['index']['title'];
 	if (!isset($pageElements[1]))
 		unset($pages['index']);
 	else
-		$pages = $pages[array_shift($pageElements)] ?? false;
+		$pages = $pages[array_shift($pageElements)] ?? [];
 	$results = getPageInformations($pages, $pageElements);
 	$results['titles_lineage'][] = $result;
 	return $results;
@@ -32,11 +39,6 @@ define('TITLES_LINEAGE', array_reverse($pageInformations['titles_lineage']));
 define('PAGE_METADATA', $pageInformations['page_metadata']);
 define('PAGE_TERMINAL', $pageInformations['terminal']);
 
-if (!TITLES_LINEAGE[array_key_last(TITLES_LINEAGE)]) {
-	http_response_code(404);
-	exit('Page not found.');
-}
-
 if (isset($_SERVER['SERVER_NAME']) !== true)
 	exit('Missing <code>$_SERVER[\'SERVER_NAME\']</code>');
 if (in_array($_SERVER['SERVER_NAME'], CONF['common']['public_domains'], true) !== true)