Merge pull request #3866 from mariobuikhuizen/fix_restore_widgets_form_saved_state

fix: restoring widgets from saved state is broken since v8 in Lab

Author: maartenbreddels

.github/workflows/tests.yml

@@ -96,7 +96,7 @@ jobs:
           pip install file://$PWD/python/ipywidgets#egg=ipywidgets[test]
       - name: Test with pytest
         run: |
-          pip install pytest
+          pip install "pytest<8"
           cd python/ipywidgets
           pytest --cov=ipywidgets ipywidgets
 

python/jupyterlab_widgets/src/manager.ts

@@ -496,6 +496,7 @@ export class WidgetManager extends LabWidgetManager {
     { loadKernel, loadNotebook } = { loadKernel: true, loadNotebook: true }
   ): Promise<void> {
     try {
+      await this.context.sessionContext.ready;
       if (loadKernel) {
         try {
           this._kernelRestoreInProgress = true;

ui-tests/tests/widgets.test.ts

@@ -40,7 +40,7 @@ test.describe('Widget Visual Regression', () => {
 
     for (let i = 0; i < cellCount; i++) {
       const image = `widgets-cell-${i}.png`;
-      expect(captures[i]).toMatchSnapshot(image);
+      expect.soft(captures[i]).toMatchSnapshot(image);
     }
   });
 });