Merge branch 'MDL-79194-402' of https://github.com/laurentdavid/moodle …

…into MOODLE_402_STABLE

course/format/amd/src/local/content.js

@@ -235,6 +235,8 @@ export default class Component extends BaseComponent {
             {watch: `transaction:start`, handler: this._startProcessing},
             {watch: `course.sectionlist:updated`, handler: this._refreshCourseSectionlist},
             {watch: `section.cmlist:updated`, handler: this._refreshSectionCmlist},
+            // Section visibility.
+            {watch: `section.visible:updated`, handler: this._reloadSection},
             // Reindex sections and cms.
             {watch: `state:updated`, handler: this._indexContents},
         ];
@@ -522,12 +524,12 @@ export default class Component extends BaseComponent {
         if (debouncedReload) {
             return debouncedReload;
         }
-        const pendingReload = new Pending(pendingKey);
         const reload = () => {
+            const pendingReload = new Pending(pendingKey);
             this.debouncedReloads.delete(pendingKey);
             const cmitem = this.getElement(this.selectors.CM, cmId);
             if (!cmitem) {
-                return;
+                return pendingReload.resolve();
             }
             const promise = Fragment.loadFragment(
                 'core_courseformat',
@@ -540,17 +542,45 @@ export default class Component extends BaseComponent {
                 }
             );
             promise.then((html, js) => {
+                // Other state change can reload the CM or the section before this one.
+                if (!document.contains(cmitem)) {
+                    pendingReload.resolve();
+                    return false;
+                }
                 Templates.replaceNode(cmitem, html, js);
                 this._indexContents();
                 pendingReload.resolve();
-                return;
-            }).catch();
+                return true;
+            }).catch(() => {
+                pendingReload.resolve();
+            });
+            return pendingReload;
         };
-        debouncedReload = debounce(reload, 200);
+        debouncedReload = debounce(
+            reload,
+            200,
+            {
+                cancel: true, pending: true
+            }
+        );
         this.debouncedReloads.set(pendingKey, debouncedReload);
         return debouncedReload;
     }
 
+    /**
+     * Cancel the active reload CM debounced function, if any.
+     * @param {Number} cmId
+     */
+    _cancelDebouncedReloadCm(cmId) {
+        const pendingKey = `courseformat/content:reloadCm_${cmId}`;
+        const debouncedReload = this.debouncedReloads.get(pendingKey);
+        if (!debouncedReload) {
+            return;
+        }
+        debouncedReload.cancel();
+        this.debouncedReloads.delete(pendingKey);
+    }
+
     /**
      * Reload a course section contents.
      *
@@ -564,6 +594,10 @@ export default class Component extends BaseComponent {
         const pendingReload = new Pending(`courseformat/content:reloadSection_${element.id}`);
         const sectionitem = this.getElement(this.selectors.SECTION, element.id);
         if (sectionitem) {
+            // Cancel any pending reload because the section will reload cms too.
+            for (const cmId of element.cmlist) {
+                this._cancelDebouncedReloadCm(cmId);
+            }
             const promise = Fragment.loadFragment(
                 'core_courseformat',
                 'section',
@@ -578,8 +612,9 @@ export default class Component extends BaseComponent {
                 Templates.replaceNode(sectionitem, html, js);
                 this._indexContents();
                 pendingReload.resolve();
-                return;
-            }).catch();
+            }).catch(() => {
+                pendingReload.resolve();
+            });
         }
     }
 

lib/amd/src/utils.js

@@ -21,6 +21,8 @@
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 
+import Pending from 'core/pending';
+
  /**
   * Create a wrapper function to throttle the execution of the given
   *
@@ -70,6 +72,11 @@ export const throttle = (func, wait) => {
     return run;
 };
 
+/**
+ * @property {Map} debounceMap A map of functions to their debounced pending promises.
+ */
+const debounceMap = new Map();
+
 /**
  * Create a wrapper function to debounce the execution of the given
  * function. Each attempt to execute the function will reset the cooldown
@@ -78,14 +85,49 @@ export const throttle = (func, wait) => {
  * @method
  * @param {Function} func The function to debounce
  * @param {Number} wait The number of milliseconds to wait after the final attempt to execute
+ * @param {Object} [options]
+ * @param {boolean} [options.pending=false] Whether to wrap the debounced method in a pending promise
+ * @param {boolean} [options.cancel=false] Whether to add a cancel method to the debounced function
  * @return {Function}
  */
-export const debounce = (func, wait) => {
+export const debounce = (
+    func,
+    wait,
+    {
+        pending = false,
+        cancel = false,
+    } = {},
+) => {
     let timeout = null;
-    return function(...args) {
+
+    const returnedFunction = (...args) => {
+        if (pending && !debounceMap.has(returnedFunction)) {
+            debounceMap.set(returnedFunction, new Pending('core/utils:debounce'));
+        }
         clearTimeout(timeout);
-        timeout = setTimeout(() => {
-            func.apply(this, args);
+        timeout = setTimeout(async() => {
+            // Get the current pending promise and immediately empty it.
+            // This is important to allow the function to be debounced again as soon as possible.
+            // We do not resolve it until later - but that's fine because the promise is appropriately scoped.
+            const pendingPromise = debounceMap.get(returnedFunction);
+            debounceMap.delete(returnedFunction);
+
+            // Allow the debounced function to return a Promise.
+            // This ensures that Behat will not continue until the function has finished executing.
+            await func.apply(this, args);
+
+            // Resolve the pending promise if it exists.
+            pendingPromise?.resolve();
         }, wait);
     };
+
+    if (cancel) {
+        returnedFunction.cancel = () => {
+            const pendingPromise = debounceMap.get(returnedFunction);
+            pendingPromise?.resolve();
+            clearTimeout(timeout);
+        };
+    }
+
+    return returnedFunction;
 };

lib/upgrade.txt

@@ -1,6 +1,11 @@
 This files describes API changes in core libraries and APIs,
 information provided here is intended especially for developers.
 
+=== 4.2.4 ===
+* Add a new parameter to the debounce (core/utils) function allow it to create its own own Pending promise.
+(via options.pending). This is a backport of patch MDL-78779.
+* Add a new parameter to the debounce (core/utils) function to allow for cancellation.
+
 === 4.2.3 ===
 * \moodle_page::set_title() has been updated to append the site name depending on the value of $CFG->sitenameintitle and whether
   the site's fullname/shortname has been set. So there's no need to manually add the site name whenever calling $PAGE->set_title().