enable turning off the variable provider (#24231)

along with microsoft/vscode#230349

let people disable the feature in case it causes perf issues

Author: amunger

package.json

@@ -680,6 +680,12 @@
                         "experimental"
                     ]
                 },
+                "python.REPL.provideVariables": {
+                    "default": true,
+                    "description": "%python.REPL.provideVariables.description%",
+                    "scope": "resource",
+                    "type": "boolean"
+                },
                 "python.testing.autoTestDiscoverOnSaveEnabled": {
                     "default": true,
                     "description": "%python.testing.autoTestDiscoverOnSaveEnabled.description%",

package.nls.json

@@ -65,6 +65,7 @@
     "python.pixiToolPath.description": "Path to the pixi executable.",
     "python.EnableREPLSmartSend.description": "Toggle Smart Send for the Python REPL. Smart Send enables sending the smallest runnable block of code to the REPL on Shift+Enter and moves the cursor accordingly.",
     "python.REPL.sendToNativeREPL.description": "Toggle to send code to Python REPL instead of the terminal on execution. Turning this on will change the behavior for both Smart Send and Run Selection/Line in the Context Menu.",
+    "python.REPL.provideVariables.description": "Toggle to provide variables for the REPL variable view for the native REPL.",
     "python.tensorBoard.logDirectory.description": "Set this setting to your preferred TensorBoard log directory to skip log directory prompt when starting TensorBoard.",
     "python.tensorBoard.logDirectory.markdownDeprecationMessage": "Tensorboard support has been moved to the extension [Tensorboard extension](https://marketplace.visualstudio.com/items?itemName=ms-toolsai.tensorboard). Instead use the setting `tensorBoard.logDirectory`.",
     "python.tensorBoard.logDirectory.deprecationMessage": "Tensorboard support has been moved to the extension Tensorboard extension. Instead use the setting `tensorBoard.logDirectory`.",

src/client/repl/variables/variablesProvider.ts

@@ -10,10 +10,12 @@ import {
     EventEmitter,
     Event,
     NotebookVariableProvider,
+    Uri,
 } from 'vscode';
 import { VariableResultCache } from './variableResultCache';
 import { IVariableDescription } from './types';
 import { VariableRequester } from './variableRequester';
+import { getConfiguration } from '../../common/vscodeApis/workspaceApis';
 
 export class VariablesProvider implements NotebookVariableProvider {
     private readonly variableResultCache = new VariableResultCache();
@@ -36,7 +38,9 @@ export class VariablesProvider implements NotebookVariableProvider {
         const notebook = this.getNotebookDocument();
         if (notebook) {
             this.executionCount += 1;
-            this._onDidChangeVariables.fire(notebook);
+            if (isEnabled(notebook.uri)) {
+                this._onDidChangeVariables.fire(notebook);
+            }
         }
     }
 
@@ -48,7 +52,12 @@ export class VariablesProvider implements NotebookVariableProvider {
         token: CancellationToken,
     ): AsyncIterable<VariablesResult> {
         const notebookDocument = this.getNotebookDocument();
-        if (token.isCancellationRequested || !notebookDocument || notebookDocument !== notebook) {
+        if (
+            !isEnabled(notebook.uri) ||
+            token.isCancellationRequested ||
+            !notebookDocument ||
+            notebookDocument !== notebook
+        ) {
             return;
         }
 
@@ -144,3 +153,7 @@ function getVariableResultCacheKey(uri: string, parent: Variable | undefined, st
     }
     return `${uri}:${parentKey}`;
 }
+
+function isEnabled(resource?: Uri) {
+    return getConfiguration('python', resource).get('REPL.provideVariables');
+}

src/test/repl/variableProvider.test.ts

@@ -2,16 +2,29 @@
 // Licensed under the MIT License.
 
 import { assert } from 'chai';
-import { NotebookDocument, CancellationTokenSource, VariablesResult, Variable, EventEmitter } from 'vscode';
+import sinon from 'sinon';
+import {
+    NotebookDocument,
+    CancellationTokenSource,
+    VariablesResult,
+    Variable,
+    EventEmitter,
+    ConfigurationScope,
+    WorkspaceConfiguration,
+} from 'vscode';
 import * as TypeMoq from 'typemoq';
 import { IVariableDescription } from '../../client/repl/variables/types';
 import { VariablesProvider } from '../../client/repl/variables/variablesProvider';
 import { VariableRequester } from '../../client/repl/variables/variableRequester';
+import * as workspaceApis from '../../client/common/vscodeApis/workspaceApis';
 
 suite('ReplVariablesProvider', () => {
     let provider: VariablesProvider;
     let varRequester: TypeMoq.IMock<VariableRequester>;
     let notebook: TypeMoq.IMock<NotebookDocument>;
+    let getConfigurationStub: sinon.SinonStub;
+    let configMock: TypeMoq.IMock<WorkspaceConfiguration>;
+    let enabled: boolean;
     const executionEventEmitter = new EventEmitter<void>();
     const cancellationToken = new CancellationTokenSource().token;
 
@@ -68,9 +81,23 @@ suite('ReplVariablesProvider', () => {
     }
 
     setup(() => {
+        enabled = true;
         varRequester = TypeMoq.Mock.ofType<VariableRequester>();
         notebook = TypeMoq.Mock.ofType<NotebookDocument>();
         provider = new VariablesProvider(varRequester.object, () => notebook.object, executionEventEmitter.event);
+        configMock = TypeMoq.Mock.ofType<WorkspaceConfiguration>();
+        configMock.setup((c) => c.get<boolean>('REPL.provideVariables')).returns(() => enabled);
+        getConfigurationStub = sinon.stub(workspaceApis, 'getConfiguration');
+        getConfigurationStub.callsFake((section?: string, _scope?: ConfigurationScope | null) => {
+            if (section === 'python') {
+                return configMock.object;
+            }
+            return undefined;
+        });
+    });
+
+    teardown(() => {
+        sinon.restore();
     });
 
     test('provideVariables without parent should yield variables', async () => {
@@ -84,6 +111,38 @@ suite('ReplVariablesProvider', () => {
         assert.equal(results[0].variable.expression, 'myObject');
     });
 
+    test('No variables are returned when variable provider is disabled', async () => {
+        enabled = false;
+        setVariablesForParent(undefined, [objectVariable]);
+
+        const results = await provideVariables(undefined);
+
+        assert.isEmpty(results);
+    });
+
+    test('No change event from provider when disabled', async () => {
+        enabled = false;
+        let eventFired = false;
+        provider.onDidChangeVariables(() => {
+            eventFired = true;
+        });
+
+        executionEventEmitter.fire();
+
+        assert.isFalse(eventFired, 'event should not have fired');
+    });
+
+    test('Variables change event from provider should fire when execution happens', async () => {
+        let eventFired = false;
+        provider.onDidChangeVariables(() => {
+            eventFired = true;
+        });
+
+        executionEventEmitter.fire();
+
+        assert.isTrue(eventFired, 'event should have fired');
+    });
+
     test('provideVariables with a parent should call get children correctly', async () => {
         const listVariableItems = [0, 1, 2].map(createListItem);
         setVariablesForParent(undefined, [objectVariable]);