Take 2

.webpack/webpack.common.js

@@ -55,7 +55,7 @@ const config = {
     alias: {
       '@': path.join(projectRootDir, 'src'),
       legacyRegistry: path.join(projectRootDir, 'src/legacyRegistry'),
-      saveAs: 'file-saver/src/FileSaver.js',
+      //saveAs: 'file-saver/src/FileSaver.js',
       csv: 'comma-separated-values',
       EventEmitter: 'eventemitter3',
       bourbon: 'bourbon.scss',
@@ -124,6 +124,7 @@ const config = {
         test: /\.vue$/,
         loader: 'vue-loader',
         options: {
+          hotReload: false,
           compilerOptions: {
             whitespace: 'preserve',
             compatConfig: {

.webpack/webpack.dev.js

@@ -13,6 +13,7 @@ const common = require('./webpack.common');
 const projectRootDir = path.resolve(__dirname, '..');
 
 module.exports = merge(common, {
+  cache: false,
   mode: 'development',
   watchOptions: {
     // Since we use require.context, webpack is watching the entire directory.
@@ -32,6 +33,7 @@ module.exports = merge(common, {
   ],
   devtool: 'eval-source-map',
   devServer: {
+    hot: false,
     devMiddleware: {
       writeToDisk: (filePathString) => {
         const filePath = path.parse(filePathString);

e2e/playwright-performance.config.js

@@ -23,7 +23,10 @@ const config = {
     ignoreHTTPSErrors: true,
     screenshot: 'off',
     trace: 'on-first-retry',
-    video: 'off'
+    video: 'off',
+    launchOptions: {
+      args: ['--js-flags=--expose-gc']
+    }
   },
   projects: [
     {

e2e/tests/performance/navigation-memory-leak-detection.perf.spec.js

@@ -0,0 +1,251 @@
+/*****************************************************************************
+ * Open MCT, Copyright (c) 2014-2023, United States Government
+ * as represented by the Administrator of the National Aeronautics and Space
+ * Administration. All rights reserved.
+ *
+ * Open MCT is licensed under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ * Open MCT includes source code licensed under additional open source
+ * licenses. See the Open Source Licenses file (LICENSES.md) included with
+ * this source code distribution or the Licensing information page available
+ * at runtime from the About dialog for additional information.
+ *****************************************************************************/
+
+const { test, expect } = require('@playwright/test');
+
+const filePath = 'e2e/test-data/memory-leak-detection.json';
+/**
+ * Executes tests to verify that views are not leaking memory on navigation away. This sort of
+ * memory leak is generally caused by a failure to clean up registered listeners.
+ *
+ * These tests are executed on a set of pre-built displays loaded from ../test-data/memory-leak-detection.json.
+ *
+ * In order to modify the test data set:
+ * 1. Run Open MCT locally (npm start)
+ * 2. Right click on a folder in the tree, and select "Import From JSON"
+ * 3. In the subsequent dialog, select the file ../test-data/memory-leak-detection.json
+ * 4. Click "OK"
+ * 5. Modify test objects as desired
+ * 6. Right click on the "Memory Leak Detection" folder, and select "Export to JSON"
+ * 7. Copy the exported file to ../test-data/memory-leak-detection.json
+ *
+ */
+test.describe('Navigation memory leak is not detected in', () => {
+  test.beforeEach(async ({ page, browser }, testInfo) => {
+    // Go to baseURL
+    await page.goto('./', { waitUntil: 'networkidle' });
+
+    // Click a:has-text("My Items")
+    await page.locator('a:has-text("My Items")').click({
+      button: 'right'
+    });
+
+    // Click text=Import from JSON
+    await page.locator('text=Import from JSON').click();
+
+    // Upload memory-leak-detection.json
+    await page.setInputFiles('#fileElem', filePath);
+
+    // Click text=OK
+    await page.locator('text=OK').click();
+
+    await expect(page.locator('a:has-text("Memory Leak Detection")')).toBeVisible();
+  });
+
+  test('plot view', async ({ page }) => {
+    const result = await navigateToObjectAndDetectMemoryLeak(page, 'overlay-plot-single-1hz-swg');
+
+    // If we got here without timing out, then the root view object was garbage collected and no memory leak was detected.
+    expect(result).toBe(true);
+  });
+
+  test('stacked plot view', async ({ page }) => {
+    const result = await navigateToObjectAndDetectMemoryLeak(page, 'stacked-plot-single-1hz-swg');
+
+    // If we got here without timing out, then the root view object was garbage collected and no memory leak was detected.
+    expect(result).toBe(true);
+  });
+
+  test.only('LAD table view', async ({ page }) => {
+    const result = await navigateToObjectAndDetectMemoryLeak(page, 'lad-table-single-1hz-swg');
+
+    // If we got here without timing out, then the root view object was garbage collected and no memory leak was detected.
+    expect(result).toBe(true);
+  });
+
+  test('LAD table set', async ({ page }) => {
+    const result = await navigateToObjectAndDetectMemoryLeak(page, 'lad-table-set-single-1hz-swg');
+
+    // If we got here without timing out, then the root view object was garbage collected and no memory leak was detected.
+    expect(result).toBe(true);
+  });
+
+  test('telemetry table view', async ({ page }) => {
+    const result = await navigateToObjectAndDetectMemoryLeak(
+      page,
+      'telemetry-table-single-1hz-swg'
+    );
+
+    // If we got here without timing out, then the root view object was garbage collected and no memory leak was detected.
+    expect(result).toBe(true);
+  });
+
+  test('notebook view', async ({ page }) => {
+    const result = await navigateToObjectAndDetectMemoryLeak(
+      page,
+      'notebook-memory-leak-detection-test'
+    );
+
+    // If we got here without timing out, then the root view object was garbage collected and no memory leak was detected.
+    expect(result).toBe(true);
+  });
+
+  test('display layout of a single SWG alphanumeric', async ({ page }) => {
+    const result = await navigateToObjectAndDetectMemoryLeak(page, 'display-layout-single-1hz-swg');
+
+    // If we got here without timing out, then the root view object was garbage collected and no memory leak was detected.
+    expect(result).toBe(true);
+  });
+
+  test('display layout of a single SWG plot', async ({ page }) => {
+    const result = await navigateToObjectAndDetectMemoryLeak(
+      page,
+      'display-layout-single-overlay-plot'
+    );
+
+    // If we got here without timing out, then the root view object was garbage collected and no memory leak was detected.
+    expect(result).toBe(true);
+  });
+
+  test.skip('example imagery view', async ({ page }) => {
+    const result = await navigateToObjectAndDetectMemoryLeak(
+      page,
+      'example-imagery-memory-leak-test'
+    );
+
+    // If we got here without timing out, then the root view object was garbage collected and no memory leak was detected.
+    expect(result).toBe(true);
+  });
+
+  test.skip('display layout of example imagery views', async ({ page }) => {
+    const result = await navigateToObjectAndDetectMemoryLeak(
+      page,
+      'display-layout-images-memory-leak-test'
+    );
+
+    // If we got here without timing out, then the root view object was garbage collected and no memory leak was detected.
+    expect(result).toBe(true);
+  });
+
+  test.skip('display layout with plots of swgs, alphanumerics, and condition sets, ', async ({
+    page
+  }) => {
+    const result = await navigateToObjectAndDetectMemoryLeak(
+      page,
+      'display-layout-simple-telemetry'
+    );
+
+    // If we got here without timing out, then the root view object was garbage collected and no memory leak was detected.
+    expect(result).toBe(true);
+  });
+
+  test.skip('flexible layout with plots of swgs', async ({ page }) => {
+    const result = await navigateToObjectAndDetectMemoryLeak(
+      page,
+      'flexible-layout-plots-memory-leak-test'
+    );
+
+    // If we got here without timing out, then the root view object was garbage collected and no memory leak was detected.
+    expect(result).toBe(true);
+  });
+
+  test.skip('flexible layout of example imagery views', async ({ page }) => {
+    const result = await navigateToObjectAndDetectMemoryLeak(
+      page,
+      'flexible-layout-images-memory-leak-test'
+    );
+
+    // If we got here without timing out, then the root view object was garbage collected and no memory leak was detected.
+    expect(result).toBe(true);
+  });
+
+  test.skip('tabbed view of display layouts and time strips', async ({ page }) => {
+    const result = await navigateToObjectAndDetectMemoryLeak(
+      page,
+      'tab-view-simple-memory-leak-test'
+    );
+
+    // If we got here without timing out, then the root view object was garbage collected and no memory leak was detected.
+    expect(result).toBe(true);
+  });
+
+  test.skip('time strip view of telemetry', async ({ page }) => {
+    const result = await navigateToObjectAndDetectMemoryLeak(
+      page,
+      'time-strip-telemetry-memory-leak-test'
+    );
+
+    // If we got here without timing out, then the root view object was garbage collected and no memory leak was detected.
+    expect(result).toBe(true);
+  });
+
+  async function navigateToObjectAndDetectMemoryLeak(page, objectName) {
+    await page.locator('[aria-label="OpenMCT Search"] input[type="search"]').click();
+    // Fill Search input
+    await page.locator('[aria-label="OpenMCT Search"] input[type="search"]').fill(objectName);
+
+    //Search Result Appears and is clicked
+    await Promise.all([
+      page.locator(`div.c-gsearch-result__title:has-text("${objectName}")`).first().click(),
+      page.waitForNavigation()
+    ]);
+
+    // Register a finalization listener on the root node for the view. This tends to be the last thing to be
+    // garbage collected since it has either direct or indirect references to all resources used by the view. Therefore it's a pretty good proxy
+    // for detecting memory leaks.
+    await page.evaluate(() => {
+      window.gcPromise = new Promise((resolve) => {
+        // eslint-disable-next-line no-undef
+        window.fr = new FinalizationRegistry(resolve);
+        window.fr.register(
+          window.openmct.layout.$refs.browseObject.$refs.objectViewWrapper.firstChild.__vnode.ctx.ctx,
+          'navigatedObject',
+          window.openmct.layout.$refs.browseObject.$refs.objectViewWrapper.firstChild.__vnode.ctx.ctx
+        );
+      });
+    });
+
+    // Nav back to folder
+    await page.goto('./#/browse/mine', { waitUntil: 'networkidle' });
+    await page.waitForNavigation();
+
+    // This next code block blocks until the finalization listener is called and the gcPromise resolved. This means that the root node for the view has been garbage collected.
+    // In the event that the root node is not garbage collected, the gcPromise will never resolve and the test will time out.
+    await page.evaluate(() => {
+      const gcPromise = window.gcPromise;
+      window.gcPromise = null;
+
+      // Manually invoke the garbage collector once all references are removed.
+      window.gc();
+
+      return gcPromise;
+    });
+
+    // Clean up the finalization registry since we don't need it any more.
+    await page.evaluate(() => {
+      window.fr = null;
+    });
+
+    // If we get here without timing out, it means the garbage collection promise resolved and the test passed.
+    return true;
+  }
+});

src/MCT.js

@@ -392,7 +392,7 @@ define([
       const component = appLayout.mount(domElement);
       component.$nextTick(() => {
         this.layout = component.$refs.layout;
-        this.app = appLayout;
+//        this.app = appLayout;
         Browse(this);
         window.addEventListener('beforeunload', this.destroy);
         this.router.start();

src/api/actions/ActionsAPI.js

@@ -22,13 +22,14 @@
 import EventEmitter from 'EventEmitter';
 import ActionCollection from './ActionCollection';
 import _ from 'lodash';
+import { markRaw } from 'vue';
 
 class ActionsAPI extends EventEmitter {
   constructor(openmct) {
     super();
 
     this._allActions = {};
-    this._actionCollections = new WeakMap();
+    this._actionCollections = markRaw(new WeakMap());
     this._openmct = openmct;
 
     this._groupOrder = ['windowing', 'undefined', 'view', 'action', 'export', 'import'];

src/exporters/CSVExporter.js

@@ -21,7 +21,7 @@
  *****************************************************************************/
 
 import CSV from 'comma-separated-values';
-import { saveAs } from 'saveAs';
+//import { saveAs } from 'saveAs';
 
 class CSVExporter {
   export(rows, options) {

src/exporters/ImageExporter.js

@@ -31,7 +31,7 @@ function replaceDotsWithUnderscores(filename) {
   return filename.replace(regex, '_');
 }
 
-import { saveAs } from 'saveAs';
+//import { saveAs } from 'saveAs';
 import html2canvas from 'html2canvas';
 import { v4 as uuid } from 'uuid';
 

src/exporters/JSONExporter.js

@@ -20,7 +20,7 @@
  * at runtime from the About dialog for additional information.
  *****************************************************************************/
 
-import { saveAs } from 'saveAs';
+//import { saveAs } from 'saveAs';
 
 class JSONExporter {
   export(obj, options) {

src/plugins/LADTable/LADTableView.js

@@ -23,6 +23,7 @@
 import LadTable from './components/LADTable.vue';
 import LADTableConfiguration from './LADTableConfiguration';
 import mount from 'utils/mount';
+import { markRaw } from 'vue';
 
 export default class LADTableView {
   constructor(openmct, domainObject, objectPath) {
@@ -31,26 +32,29 @@ export default class LADTableView {
     this.objectPath = objectPath;
     this.component = null;
     this._destroy = null;
+    markRaw(this);
   }
 
   show(element) {
     let ladTableConfiguration = new LADTableConfiguration(this.domainObject, this.openmct);
+    const domainObject = this.domainObject;
+    const objectPath = this.objectPath;
 
     const { vNode, destroy } = mount(
       {
         el: element,
         components: {
-          LadTable
+          LadTable: Object.create(LadTable)
         },
         provide: {
           openmct: this.openmct,
-          currentView: this,
-          ladTableConfiguration
+          //currentView: markRaw(this),
+          ladTableConfiguration: markRaw(ladTableConfiguration)
         },
         data: () => {
           return {
-            domainObject: this.domainObject,
-            objectPath: this.objectPath
+            domainObject,
+            objectPath
           };
         },
         template:
@@ -77,5 +81,7 @@ export default class LADTableView {
     if (this._destroy) {
       this._destroy();
     }
+    //this.openmct.app._context.optionsCache.delete(LadTable);
+    //this.openmct.app._context.optionsCache = new WeakMap();
   }
 }

src/plugins/LADTable/components/LADTable.vue

@@ -49,7 +49,7 @@
 </template>
 
 <script>
-import Vue, { toRaw } from 'vue';
+import Vue, { toRaw, markRaw } from 'vue';
 import LadRow from './LADRow.vue';
 import StalenessUtils from '@/utils/staleness';
 
@@ -139,8 +139,9 @@ export default {
     );
     this.initializeViewActions();
   },
-  unmounted() {
+  beforeUnmounted() {
     this.ladTableConfiguration.off('change', this.handleConfigurationChange);
+    this.ladTableConfiguration.destroy();
 
     this.composition.off('add', this.addItem);
     this.composition.off('remove', this.removeItem);
@@ -150,6 +151,8 @@ export default {
       stalenessSubscription.unsubscribe();
       stalenessSubscription.stalenessUtils.destroy();
     });
+    this.viewActionsCollection.destroy();
+    delete this.viewActionsCollection;
   },
   methods: {
     addItem(domainObject) {

src/plugins/notebook/actions/ExportNotebookAsTextAction.js

@@ -1,4 +1,4 @@
-import { saveAs } from 'saveAs';
+//import { saveAs } from 'saveAs';
 import Moment from 'moment';
 import { NOTEBOOK_TYPE, RESTRICTED_NOTEBOOK_TYPE } from '../notebook-constants';
 const UNKNOWN_USER = 'Unknown';

src/ui/mixins/context-menu-gesture.js

@@ -26,7 +26,7 @@ export default {
       const rawOldObject = toRaw(oldObject);
       Object.assign(rawOldObject, rawNewObject);
     }
-
+    this.unobservers = [];
     this.objectPath.forEach((object) => {
       if (object) {
         const unobserve = this.openmct.objects.observe(
@@ -34,12 +34,13 @@ export default {
           '*',
           updateObject.bind(this, object)
         );
-        this.$once('hook:unmounted', unobserve);
+        this.unobservers.push(unobserve);
       }
     });
   },
   beforeUnmount() {
     this.$refs.root.removeEventListener('contextMenu', this.showContextMenu);
+    this.unobservers.forEach((unobserve) => unobserve());
   },
   methods: {
     showContextMenu(event) {

src/utils/mount.js

@@ -20,6 +20,9 @@ export default function mount(component, { props, children, element, app } = {})
     }
     el = null;
     vNode = null;
+//    if (app && app._context) {
+//      app._context.optionsCache.delete(component);
+//    }
   };
 
   return { vNode, destroy, el };