fix(workbench/view): prevent closing views with a pending CanClose …

…guard

The router no longer invokes a view's `CanClose` guard if the view is already pending confirmation from a previous close attempt.

apps/workbench-testing-app/src/app/test-pages/blocking-can-close-test-page/blocking-can-close-test-page.component.ts

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2018-2024 Swiss Federal Railways
+ *
+ * This program and the accompanying materials are made
+ * available under the terms of the Eclipse Public License 2.0
+ * which is available at https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+
+import {Component, inject} from '@angular/core';
+import {WorkbenchView} from '@scion/workbench';
+import {noop} from 'rxjs';
+
+@Component({
+  selector: 'app-blocking-can-close-test-page',
+  template: 'Blocking CanClose Test Page',
+  standalone: true,
+})
+export default class BlockingCanCloseTestPageComponent {
+
+  constructor() {
+    inject(WorkbenchView).canClose(() => {
+      console.debug('[BlockingCanCloseTestPageComponent] BLOCKING');
+      return new Promise<boolean>(noop);
+    });
+  }
+}

apps/workbench-testing-app/src/app/test-pages/routes.ts

@@ -63,6 +63,10 @@ export default [
     path: 'size-test-page',
     loadComponent: () => import('./size-test-page/size-test-page.component'),
   },
+  {
+    path: 'blocking-can-close-test-page',
+    loadComponent: () => import('./blocking-can-close-test-page/blocking-can-close-test-page.component'),
+  },
 ] satisfies Routes;
 
 /**

projects/scion/e2e-testing/src/workbench/view.e2e-spec.ts

@@ -830,6 +830,38 @@ test.describe('Workbench View', () => {
     await expectView(testViewPage).not.toBeAttached();
   });
 
+  test('should not invoke `CanClose` guard while blocking', async ({appPO, workbenchNavigator, consoleLogs}) => {
+    await appPO.navigateTo({microfrontendSupport: false});
+
+    // Open view.
+    const routerPage = await workbenchNavigator.openInNewTab(RouterPagePO);
+    await routerPage.navigate(['test-pages/blocking-can-close-test-page'], {target: 'view.100'});
+    const testView = appPO.view({viewId: 'view.100'});
+
+    // Close view.
+    await testView.tab.close();
+
+    // Expect `CanClose` guard to be invoked.
+    await expect.poll(() => consoleLogs.get()).toContain('[BlockingCanCloseTestPageComponent] BLOCKING');
+
+    // Clear log.
+    consoleLogs.clear();
+
+    // Expect view not to be closable until `CanClose` guard is released.
+    await expect(testView.tab.closeButton).not.toBeVisible();
+
+    // Close all views.
+    await routerPage.view.tab.click();
+    const contextMenu = await routerPage.view.tab.openContextMenu();
+    await contextMenu.menuItems.closeAll.click();
+
+    // Expect `CanClose` guard not to be invoked again.
+    await expect.poll(() => consoleLogs.get()).not.toContain('[BlockingCanCloseTestPageComponent] BLOCKING');
+
+    // Expect view not to be closable until `CanClose` guard is released.
+    await expect(testView.tab.closeButton).not.toBeVisible();
+  });
+
   test(`should disable context menu 'Close tab' for 'non-closable' view`, async ({appPO, workbenchNavigator}) => {
     await appPO.navigateTo({microfrontendSupport: false});
 

projects/scion/workbench/src/lib/routing/ɵworkbench-router.service.ts

@@ -198,11 +198,18 @@ export class ɵWorkbenchRouter implements WorkbenchRouter {
       .map(async view => {
         // Capture current navigation id to not proceed closing if navigated in the meantime.
         const navigationId = view.navigationId;
-        const close = await view.canCloseGuard!();
-        if (close && view.navigationId === navigationId) {
-          return this.navigate(layout => layout.removeView(view.id, {force: true}));
+        // Make view non-closable to prevent closing the view again while awaiting closing confirmation.
+        view.closable = false;
+        try {
+          const close = await view.canCloseGuard!();
+          if (close && view.navigationId === navigationId) {
+            return this.navigate(layout => layout.removeView(view.id, {force: true}));
+          }
+          return true;
+        }
+        finally {
+          view.closable = true;
         }
-        return true;
       });
 
     // Wait for all `CanClose` guards to resolve and subsequent navigations to complete.