show variable view only when applicable (microsoft#204789)

* only initialize view if there is a variable provider available

* use context key to show/hide the view

src/vs/workbench/contrib/notebook/browser/contrib/notebookVariables/notebookVariableContextKeys.ts

@@ -0,0 +1,8 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import { RawContextKey } from 'vs/platform/contextkey/common/contextkey';
+
+export const NOTEBOOK_VARIABLE_VIEW_ENABLED = new RawContextKey<boolean>('notebookVariableViewEnabled', false);

src/vs/workbench/contrib/notebook/browser/contrib/notebookVariables/notebookVariables.ts

@@ -9,40 +9,75 @@ import { IWorkbenchContribution } from 'vs/workbench/common/contributions';
 import { Registry } from 'vs/platform/registry/common/platform';
 import { Extensions, IViewContainersRegistry, IViewsRegistry } from 'vs/workbench/common/views';
 import { VIEWLET_ID as debugContainerId } from 'vs/workbench/contrib/debug/common/debug';
-import { ContextKeyExpr } from 'vs/platform/contextkey/common/contextkey';
 import { SyncDescriptor } from 'vs/platform/instantiation/common/descriptors';
 import { NotebookVariablesView } from 'vs/workbench/contrib/notebook/browser/contrib/notebookVariables/notebookVariablesView';
-import { NOTEBOOK_KERNEL } from 'vs/workbench/contrib/notebook/common/notebookContextKeys';
 import { variablesViewIcon } from 'vs/workbench/contrib/notebook/browser/notebookIcons';
 import { IEditorService } from 'vs/workbench/services/editor/common/editorService';
-import { IConfigurationService } from 'vs/platform/configuration/common/configuration';
+import { IConfigurationChangeEvent, IConfigurationService } from 'vs/platform/configuration/common/configuration';
 import { INotebookExecutionStateService } from 'vs/workbench/contrib/notebook/common/notebookExecutionStateService';
 import { NotebookSetting } from 'vs/workbench/contrib/notebook/common/notebookCommon';
+import { getNotebookEditorFromEditorPane } from 'vs/workbench/contrib/notebook/browser/notebookBrowser';
+import { INotebookKernelService } from 'vs/workbench/contrib/notebook/common/notebookKernelService';
+import { IContextKey, IContextKeyService } from 'vs/platform/contextkey/common/contextkey';
+import { NOTEBOOK_VARIABLE_VIEW_ENABLED } from 'vs/workbench/contrib/notebook/browser/contrib/notebookVariables/notebookVariableContextKeys';
 
 
 export class NotebookVariables extends Disposable implements IWorkbenchContribution {
 	private listeners: IDisposable[] = [];
+	private configListener: IDisposable;
+	private initialized = false;
+
+	private viewEnabled: IContextKey<boolean>;
 
 	constructor(
+		@IContextKeyService contextKeyService: IContextKeyService,
+		@IConfigurationService private readonly configurationService: IConfigurationService,
 		@IEditorService private readonly editorService: IEditorService,
-		@IConfigurationService configurationService: IConfigurationService,
-		@INotebookExecutionStateService private readonly notebookExecutionStateService: INotebookExecutionStateService
+		@INotebookExecutionStateService private readonly notebookExecutionStateService: INotebookExecutionStateService,
+		@INotebookKernelService private readonly notebookKernelService: INotebookKernelService
 	) {
 		super();
 
-		this.listeners.push(this.editorService.onDidEditorsChange(() => this.handleInitEvent(configurationService)));
-		this.listeners.push(this.notebookExecutionStateService.onDidChangeExecution(() => this.handleInitEvent(configurationService)));
+		this.viewEnabled = NOTEBOOK_VARIABLE_VIEW_ENABLED.bindTo(contextKeyService);
+
+		this.listeners.push(this.editorService.onDidEditorsChange(() => this.handleInitEvent()));
+		this.listeners.push(this.notebookExecutionStateService.onDidChangeExecution(() => this.handleInitEvent()));
+
+		this.configListener = configurationService.onDidChangeConfiguration((e) => this.handleConfigChange(e));
+	}
+
+	private handleConfigChange(e: IConfigurationChangeEvent) {
+		if (e.affectsConfiguration(NotebookSetting.notebookVariablesView)) {
+			if (!this.configurationService.getValue(NotebookSetting.notebookVariablesView)) {
+				this.viewEnabled.set(false);
+			} else if (this.initialized) {
+				this.viewEnabled.set(true);
+			} else {
+				this.handleInitEvent();
+			}
+		}
 	}
 
-	private handleInitEvent(configurationService: IConfigurationService) {
-		if (configurationService.getValue(NotebookSetting.notebookVariablesView)
+	private handleInitEvent() {
+		if (this.configurationService.getValue(NotebookSetting.notebookVariablesView)
 			&& this.editorService.activeEditorPane?.getId() === 'workbench.editor.notebook') {
-			if (this.initializeView()) {
+
+			if (this.hasVariableProvider()) {
+				this.viewEnabled.set(true);
+			}
+
+			if (!this.initialized && this.initializeView()) {
+				this.initialized = true;
 				this.listeners.forEach(listener => listener.dispose());
 			}
 		}
 	}
 
+	private hasVariableProvider() {
+		const notebookDocument = getNotebookEditorFromEditorPane(this.editorService.activeEditorPane)?.getViewModel()?.notebookDocument;
+		return notebookDocument && this.notebookKernelService.getMatchingKernel(notebookDocument).selected?.hasVariableProvider;
+	}
+
 	private initializeView() {
 		const debugViewContainer = Registry.as<IViewContainersRegistry>('workbench.registry.view.containers').get(debugContainerId);
 
@@ -51,7 +86,7 @@ export class NotebookVariables extends Disposable implements IWorkbenchContribut
 			const viewDescriptor = {
 				id: 'NOTEBOOK_VARIABLES', name: nls.localize2('notebookVariables', "Notebook Variables"),
 				containerIcon: variablesViewIcon, ctorDescriptor: new SyncDescriptor(NotebookVariablesView),
-				order: 50, weight: 5, canToggleVisibility: true, canMoveView: true, collapsed: true, when: ContextKeyExpr.notEquals(NOTEBOOK_KERNEL.key, ''),
+				order: 50, weight: 5, canToggleVisibility: true, canMoveView: true, collapsed: true, when: NOTEBOOK_VARIABLE_VIEW_ENABLED,
 			};
 
 			viewsRegistry.registerViews([viewDescriptor], debugViewContainer);
@@ -61,4 +96,10 @@ export class NotebookVariables extends Disposable implements IWorkbenchContribut
 		return false;
 	}
 
+	override dispose(): void {
+		super.dispose();
+		this.listeners.forEach(listener => listener.dispose());
+		this.configListener.dispose();
+	}
+
 }

src/vs/workbench/contrib/notebook/browser/contrib/notebookVariables/notebookVariablesDataSource.ts

@@ -53,7 +53,7 @@ export class NotebookVariableDataSource implements IAsyncDataSource<INotebookSco
 		}
 	}
 
-	async getVariables(parent: INotebookVariableElement): Promise<INotebookVariableElement[]> {
+	private async getVariables(parent: INotebookVariableElement): Promise<INotebookVariableElement[]> {
 		const selectedKernel = this.notebookKernelService.getMatchingKernel(parent.notebook).selected;
 		if (selectedKernel && selectedKernel.hasVariableProvider) {
 
@@ -75,7 +75,7 @@ export class NotebookVariableDataSource implements IAsyncDataSource<INotebookSco
 		return [];
 	}
 
-	async getIndexedChildren(parent: INotebookVariableElement, kernel: INotebookKernel) {
+	private async getIndexedChildren(parent: INotebookVariableElement, kernel: INotebookKernel) {
 		const childNodes: INotebookVariableElement[] = [];
 
 		if (parent.indexedChildrenCount > variablePageSize) {
@@ -128,7 +128,7 @@ export class NotebookVariableDataSource implements IAsyncDataSource<INotebookSco
 		return childNodes;
 	}
 
-	async getRootVariables(notebook: NotebookTextModel): Promise<INotebookVariableElement[]> {
+	private async getRootVariables(notebook: NotebookTextModel): Promise<INotebookVariableElement[]> {
 		const selectedKernel = this.notebookKernelService.getMatchingKernel(notebook).selected;
 		if (selectedKernel && selectedKernel.hasVariableProvider) {
 			const variables = selectedKernel.provideVariables(notebook.uri, undefined, 'named', 0, this.cancellationTokenSource.token);