Force redirect when input categories do not match stored categories i…

…n general questions

qa-include/pages/questions.php

@@ -29,13 +29,17 @@
 require_once QA_INCLUDE_DIR . 'app/q-list.php';
 
 $categoryslugs = qa_request_parts(1);
-$countslugs = count($categoryslugs);
+$hasSlugs = !empty($categoryslugs);
+$sort = qa_get('sort');
+
+if (!QA_ALLOW_UNINDEXED_QUERIES && $hasSlugs) {
+	$getParams = $sort === null ? [] : ['sort' => $sort];
+	qa_redirect('questions', $getParams);
+}
 
-$sort = ($countslugs && !QA_ALLOW_UNINDEXED_QUERIES) ? null : qa_get('sort');
 $start = qa_get_start();
 $userid = qa_get_logged_in_userid();
 
-
 // Get list of questions, plus category information
 
 switch ($sort) {
@@ -63,75 +67,76 @@
 list($questions, $categories, $categoryid) = qa_db_select_with_pending(
 	qa_db_qs_selectspec($userid, $selectsort, $start, $categoryslugs, null, false, false, qa_opt_if_loaded('page_size_qs')),
 	qa_db_category_nav_selectspec($categoryslugs, false, false, true),
-	$countslugs ? qa_db_slugs_to_category_id_selectspec($categoryslugs) : null
+	$hasSlugs ? qa_db_slugs_to_category_id_selectspec($categoryslugs) : null
 );
 
-if ($countslugs) {
+if ($hasSlugs) {
 	if (!isset($categoryid)) {
 		return include QA_INCLUDE_DIR . 'qa-page-not-found.php';
 	}
 
+	if ($categories[$categoryid]['backpath'] !== qa_db_slugs_to_backpath($categoryslugs)) {
+		$expectedPathInUrl = implode('/', array_reverse(explode('/', $categories[$categoryid]['backpath'])));
+		$getParams = $sort === null ? [] : ['sort' => $sort];
+		qa_redirect('questions/' . $expectedPathInUrl, $getParams);
+	}
+
 	$categorytitlehtml = qa_html($categories[$categoryid]['title']);
 	$nonetitle = qa_lang_html_sub('main/no_questions_in_x', $categorytitlehtml);
-
 } else {
 	$nonetitle = qa_lang_html('main/no_questions_found');
 }
 
-
 $categorypathprefix = QA_ALLOW_UNINDEXED_QUERIES ? 'questions/' : null; // this default is applied if sorted not by recent
 $feedpathprefix = null;
 $linkparams = array('sort' => $sort);
 
 switch ($sort) {
 	case 'hot':
-		$sometitle = $countslugs ? qa_lang_html_sub('main/hot_qs_in_x', $categorytitlehtml) : qa_lang_html('main/hot_qs_title');
+		$sometitle = $hasSlugs ? qa_lang_html_sub('main/hot_qs_in_x', $categorytitlehtml) : qa_lang_html('main/hot_qs_title');
 		$feedpathprefix = qa_opt('feed_for_hot') ? 'hot' : null;
 		break;
 
 	case 'votes':
-		$sometitle = $countslugs ? qa_lang_html_sub('main/voted_qs_in_x', $categorytitlehtml) : qa_lang_html('main/voted_qs_title');
+		$sometitle = $hasSlugs ? qa_lang_html_sub('main/voted_qs_in_x', $categorytitlehtml) : qa_lang_html('main/voted_qs_title');
 		break;
 
 	case 'answers':
-		$sometitle = $countslugs ? qa_lang_html_sub('main/answered_qs_in_x', $categorytitlehtml) : qa_lang_html('main/answered_qs_title');
+		$sometitle = $hasSlugs ? qa_lang_html_sub('main/answered_qs_in_x', $categorytitlehtml) : qa_lang_html('main/answered_qs_title');
 		break;
 
 	case 'views':
-		$sometitle = $countslugs ? qa_lang_html_sub('main/viewed_qs_in_x', $categorytitlehtml) : qa_lang_html('main/viewed_qs_title');
+		$sometitle = $hasSlugs ? qa_lang_html_sub('main/viewed_qs_in_x', $categorytitlehtml) : qa_lang_html('main/viewed_qs_title');
 		break;
 
 	default:
 		$linkparams = array();
-		$sometitle = $countslugs ? qa_lang_html_sub('main/recent_qs_in_x', $categorytitlehtml) : qa_lang_html('main/recent_qs_title');
-		$categorypathprefix = 'questions/';
+		$sometitle = $hasSlugs ? qa_lang_html_sub('main/recent_qs_in_x', $categorytitlehtml) : qa_lang_html('main/recent_qs_title');
 		$feedpathprefix = qa_opt('feed_for_questions') ? 'questions' : null;
 		break;
 }
 
-
 // Prepare and return content for theme
 
 $qa_content = qa_q_list_page_content(
 	$questions, // questions
 	qa_opt('page_size_qs'), // questions per page
 	$start, // start offset
-	$countslugs ? $categories[$categoryid]['qcount'] : qa_opt('cache_qcount'), // total count
+	$hasSlugs ? $categories[$categoryid]['qcount'] : qa_opt('cache_qcount'), // total count
 	$sometitle, // title if some questions
 	$nonetitle, // title if no questions
 	$categories, // categories for navigation
 	$categoryid, // selected category id
 	true, // show question counts in category navigation
 	$categorypathprefix, // prefix for links in category navigation
 	$feedpathprefix, // prefix for RSS feed paths
-	$countslugs ? qa_html_suggest_qs_tags(qa_using_tags()) : qa_html_suggest_ask($categoryid), // suggest what to do next
+	$hasSlugs ? qa_html_suggest_qs_tags(qa_using_tags()) : qa_html_suggest_ask($categoryid), // suggest what to do next
 	$linkparams, // extra parameters for page links
 	$linkparams // category nav params
 );
 
-if (QA_ALLOW_UNINDEXED_QUERIES || !$countslugs) {
+if (QA_ALLOW_UNINDEXED_QUERIES || !$hasSlugs) {
 	$qa_content['navigation']['sub'] = qa_qs_sub_navigation($sort, $categoryslugs);
 }
 
-
 return $qa_content;