From 93289564e0eb3e862903c9bf168d6d73ef5f712e Mon Sep 17 00:00:00 2001
From: Khoa Nguyen <knd39@open.ac.uk>
Date: Fri, 22 Nov 2024 10:54:21 +0700
Subject: [PATCH] MDL-83778 quiz: prevent page caching for quiz view page

---
 mod/quiz/tests/behat/attempt_begin.feature | 17 +++++++++++++++++
 mod/quiz/view.php                          |  2 ++
 2 files changed, 19 insertions(+)

diff --git a/mod/quiz/tests/behat/attempt_begin.feature b/mod/quiz/tests/behat/attempt_begin.feature
index 1b7508ae1a1..c1e53857d23 100644
--- a/mod/quiz/tests/behat/attempt_begin.feature
+++ b/mod/quiz/tests/behat/attempt_begin.feature
@@ -104,3 +104,20 @@ Feature: The various checks that may happen when an attept is started
     And I press "Cancel"
     Then I should see "Quiz 1 description"
     And "Attempt quiz" "button" should be visible
+
+  @javascript
+  Scenario: Quiz attempt page reloads upon navigating back using the browser's back button
+    Given the following "activities" exist:
+      | activity   | name   | intro              | course | idnumber | timelimit |
+      | quiz       | Quiz 1 | Quiz 1 description | C1     | quiz1    | 3600      |
+    And quiz "Quiz 1" contains the following questions:
+      | question | page |
+      | TF1      | 1    |
+    When I am on the "Quiz 1" "mod_quiz > View" page logged in as "student"
+    And I press "Attempt quiz"
+    And I should see "Your attempt will have a time limit of 1 hour. When you " in the "Start attempt" "dialogue"
+    And I start watching to see if a new page loads
+    And I click on "Start attempt" "button" in the "Start attempt" "dialogue"
+    And I press the "back" button in the browser
+    Then a new page should have loaded since I started watching
+    And I should see "Continue your attempt"
diff --git a/mod/quiz/view.php b/mod/quiz/view.php
index 7da171c8d3d..8bf1d0107b3 100644
--- a/mod/quiz/view.php
+++ b/mod/quiz/view.php
@@ -68,6 +68,8 @@ quiz_view($quiz, $course, $cm, $context);
 
 // Initialize $PAGE, compute blocks.
 $PAGE->set_url('/mod/quiz/view.php', ['id' => $cm->id]);
+// On the quiz view page, the browser back/forwards buttons should force a reload.
+$PAGE->set_cacheable(false);
 
 // Create view object which collects all the information the renderer will need.
 $viewobj = new view_page();