From 9f60cb0ae5e3250ac21a53548742f4484de415a4 Mon Sep 17 00:00:00 2001
From: Paul Holden <paulh@moodle.com>
Date: Thu, 9 Jan 2025 15:34:03 +0000
Subject: [PATCH] MDL-84140 course: more resilient check for activity footer
 component.

---
 course/externallib.php | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/course/externallib.php b/course/externallib.php
index c4825433f0e..177f779fd9e 100644
--- a/course/externallib.php
+++ b/course/externallib.php
@@ -4616,9 +4616,17 @@ class core_course_external extends external_api {
         $coursecontext = context_course::instance($courseid);
         self::validate_context($coursecontext);
 
-        $activeplugin = get_config('core', 'activitychooseractivefooter');
+        // The active plugin must be set, and be present on the site.
+        $activeplugin = clean_param(
+            get_config('core', 'activitychooseractivefooter'),
+            PARAM_COMPONENT,
+        );
 
-        if ($activeplugin !== COURSE_CHOOSER_FOOTER_NONE) {
+        if (
+            $activeplugin !== COURSE_CHOOSER_FOOTER_NONE &&
+            !empty($activeplugin) &&
+            core_component::get_component_directory($activeplugin) !== null
+        ) {
             $footerdata = component_callback($activeplugin, 'custom_chooser_footer', [$courseid, $sectionid]);
             return [
                 'footer' => true,