Merge branch 'MDL-83943-500' of https://github.com/meirzamoodle/moodle into MOODLE_500_STABLE

tag/tests/taglib_test.php

@@ -28,6 +28,7 @@ use core_tag;
  * @category test
  * @copyright 2014 Mark Nelson <[email protected]>
  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @covers \core_tag_tag
  */
 final class taglib_test extends \advanced_testcase {
 
@@ -1904,6 +1905,91 @@ final class taglib_test extends \advanced_testcase {
         core_tag_tag::change_instances_context([$fooinstance1->id], $context2);
     }
 
+    /**
+     * Tests user pagination works correctly for filtered users.
+     */
+    public function test_user_get_tagged_users(): void {
+        global $DB;
+
+        // Create some users.
+        $users = [];
+        for ($i = 0; $i < 11; $i++) {
+            $users[] = $this->getDataGenerator()->create_user();
+        }
+
+        // Create the tag.
+        $tagcollid = core_tag_collection::get_default();
+        $tag = $this->getDataGenerator()->create_tag(['tagcollid' => $tagcollid, 'rawname' => 'bike']);
+
+        // Add the tag to the users.
+        for ($i = 0; $i < count($users); $i++) {
+            core_tag_tag::add_item_tag('core', 'user', $users[$i]->id,
+                    \context_user::instance($users[$i]->id), 'bike');
+        }
+
+        // The logged-in user.
+        $this->setUser($users[0]);
+
+        // Get the tagged users.
+        $tag = core_tag_tag::get($tag->id, '*');
+        $taggedusers = user_get_tagged_users($tag);
+
+        // Ensure it has content.
+        $this->assertEquals(1, $taggedusers->hascontent);
+
+        // Ensure it should have 1 user and the "more" link is hidden (null).
+        $this->assertEquals(1, $this->count_html_elements($taggedusers->content, 'li'));
+        $this->assertNull($taggedusers->nextpageurl);
+
+        // Test which users are visible to the logged-in user based on the course.
+        // Create a course to tag.
+        $course = $this->getDataGenerator()->create_course();
+        $studentrole = $DB->get_record('role', ['shortname' => 'student']);
+        for ($i = 0; $i < count($users); $i++) {
+            // Enrol only some users (0, 2, 4, 6, 8, 10).
+            if ($i % 2 === 0) {
+                $this->getDataGenerator()->enrol_user($users[$i]->id, $course->id, $studentrole->id);
+            }
+        }
+
+        // First page should have 5 users and the "more" link is visible (not null).
+        $taggedusers = user_get_tagged_users(
+            tag: $tag,
+            page: 0,
+        );
+        $this->assertNotNull($taggedusers->nextpageurl);
+        $this->assertEquals(5, $this->count_html_elements($taggedusers->content, 'li'));
+
+        // Second page should have 1 user and the "more" link is hidden (null).
+        $taggedusers = user_get_tagged_users(
+            tag: $tag,
+            page: 1,
+        );
+        $this->assertNull($taggedusers->nextpageurl);
+        $this->assertEquals(1, $this->count_html_elements($taggedusers->content, 'li'));
+    }
+
+    /**
+     * Counts the number of specified HTML elements in a given HTML string.
+     *
+     * @param string $html The HTML string to be parsed.
+     * @param string $tagname The name of the HTML tag to count (e.g., 'li', 'div').
+     * @return int The number of elements with the specified tag name found in the HTML.
+     */
+    private function count_html_elements(string $html, string $tagname): int {
+        // Load the HTML into DOMDocument.
+        $dom = new \DOMDocument();
+        libxml_use_internal_errors(true); // Suppress warnings for invalid HTML.
+        $dom->loadHTML($html);
+        libxml_clear_errors();
+
+        // Find all elements with the specified tag name.
+        $elements = $dom->getElementsByTagName($tagname);
+
+        // Count the number of elements.
+        return $elements->length;
+    }
+
     /**
      * Help method to return sorted array of names of correlated tags to use for assertions
      * @param core_tag $tag

user/lib.php

@@ -1291,32 +1291,64 @@ function user_can_view_profile($user, $course = null, $usercontext = null) {
 function user_get_tagged_users($tag, $exclusivemode = false, $fromctx = 0, $ctx = 0, $rec = 1, $page = 0) {
     global $PAGE;
 
-    if ($ctx && $ctx != context_system::instance()->id) {
-        $usercount = 0;
-    } else {
-        // Users can only be displayed in system context.
-        $usercount = $tag->count_tagged_items('core', 'user',
-                'it.deleted=:notdeleted', array('notdeleted' => 0));
-    }
     $perpage = $exclusivemode ? 24 : 5;
-    $content = '';
-    $excludedusers = 0;
+    $filteredusers = []; // Initialize an array to hold users that pass filtering.
 
-    if ($usercount) {
-        $userlist = $tag->get_tagged_items('core', 'user', $page * $perpage, $perpage,
-                'it.deleted=:notdeleted', array('notdeleted' => 0));
-        foreach ($userlist as $user) {
-            if (!user_can_view_profile($user)) {
-                unset($userlist[$user->id]);
-                $excludedusers++;
+    $totalusers = $tag->count_tagged_items('core', 'user', 'it.deleted=:notdeleted', ['notdeleted' => 0]);
+    $withinuserlimit = ($page * $perpage < $totalusers);
+    // Check if the requested page is within the user limit and if the context is valid or matches the system context.
+    if ($withinuserlimit && (!$ctx || $ctx == context_system::instance()->id)) {
+        // The output from get_tagged_items() will be filtered to check if users are visible to the current user.
+        // It’s possible that the count of users meeting the filtering criteria may fall short of the per-page limit,
+        // necessitating additional data beyond this limit.
+        // Implementing a batch approach addressed this issue by minimizing database queries.
+        $batch = 0;
+        // Increase the per-page limit to create a batch size for chunked querying.
+        // If the first chunk $perpagebatch doesn't return enough users, fetch the next chunk without re-querying the database.
+        $perpagebatch = $perpage * 2;
+
+        do {
+            $userlist = $tag->get_tagged_items(
+                component: 'core',
+                itemtype: 'user',
+                limitfrom: $perpagebatch * $batch,
+                limitnum: $perpagebatch,
+                subquery: 'it.deleted=:notdeleted',
+                params: ['notdeleted' => 0],
+            );
+
+            foreach ($userlist as $user) {
+                // Check if the user profile can be viewed.
+                if (user_can_view_profile($user)) {
+                    $filteredusers[] = $user;
+                    // If enough users have been collected for the requested page, exit both loops.
+                    if (count($filteredusers) > $perpage * ($page + 1)) {
+                        break 2;
+                    }
+                }
             }
-        }
+
+            $batch++;
+
+        } while (count($userlist) > 0); // If all the data is still insufficient, run another batch.
+
+    }
+
+    $usercount = count($filteredusers);
+
+    // Initialize the content to display tagged users.
+    $content = '';
+    if ($usercount > 0) {
+        // Prepare the paginated list of users, limiting it to the number of users per page.
+        $paginatedusers = array_slice($filteredusers, $page * $perpage, $perpage);
+
+        // Get the renderer for the user module to create the user list content.
         $renderer = $PAGE->get_renderer('core', 'user');
-        $content .= $renderer->user_list($userlist, $exclusivemode);
+        $content = $renderer->user_list($paginatedusers, $exclusivemode);
     }
 
     // Calculate the total number of pages.
-    $totalpages = ceil(($usercount - $excludedusers) / $perpage);
+    $totalpages = ceil($usercount / $perpage);
 
     return new core_tag\output\tagindex($tag, 'core', 'user', $content,
             $exclusivemode, $fromctx, $ctx, $rec, $page, $totalpages);