Ensure we do not switch kernel if already the same (microsoft#13297)

Author: DonJayamanne

src/client/datascience/jupyter/kernels/kernel.ts

@@ -32,7 +32,7 @@ export class Kernel implements IKernel {
  if (this._notebook) {
  return this._notebook.getKernelSpec();
  }
- return this._metadata.kernelSpec || this._metadata.kernelModel;
+ return this.metadata.kernelSpec || this.metadata.kernelModel;
  }
  get onStatusChanged(): Event<ServerStatus> {
  return this._onStatusChanged.event;
@@ -63,7 +63,7 @@ export class Kernel implements IKernel {
  private restarting?: Deferred<void>;
  constructor(
  public readonly uri: Uri,
- private readonly _metadata: KernelSelection,
+ public readonly metadata: Readonly<KernelSelection>,
  private readonly notebookProvider: INotebookProvider,
  private readonly disposables: IDisposableRegistry,
  private readonly waitForIdleTimeoutMs: number,
@@ -93,8 +93,8 @@ export class Kernel implements IKernel {
  const metadata = ((getDefaultNotebookContent().metadata || {}) as unknown) as nbformat.INotebookMetadata;
  updateNotebookMetadata(
  metadata,
- this._metadata.interpreter,
- this._metadata.kernelSpec || this._metadata.kernelModel
+ this.metadata.interpreter,
+ this.metadata.kernelSpec || this.metadata.kernelModel
  );
 
  this._notebookPromise = this.notebookProvider.getOrCreateNotebook({

src/client/datascience/jupyter/kernels/kernelProvider.ts

@@ -3,6 +3,7 @@
 
 'use strict';
 
+import * as fastDeepEqual from 'fast-deep-equal';
 import { inject, injectable } from 'inversify';
 import { Uri } from 'vscode';
 import { traceWarning } from '../../../common/logger';
@@ -25,10 +26,7 @@ export class KernelProvider {
  }
  public getOrCreate(uri: Uri, options: KernelOptions): IKernel | undefined {
  const existingKernelInfo = this.kernelsByUri.get(uri.toString());
- if (
- existingKernelInfo &&
- JSON.stringify(existingKernelInfo.options.metadata) === JSON.stringify(options.metadata)
- ) {
+ if (existingKernelInfo && fastDeepEqual(existingKernelInfo.options.metadata, options.metadata)) {
  return existingKernelInfo.kernel;
  }
 

src/client/datascience/jupyter/kernels/types.ts

@@ -57,6 +57,7 @@ export interface IKernelSelectionUsage {
 export interface IKernel extends IAsyncDisposable {
  readonly uri: Uri;
  readonly kernelSpec?: IJupyterKernelSpec | LiveKernelModel;
+ readonly metadata: Readonly<KernelSelection>;
  readonly onStatusChanged: Event<ServerStatus>;
  readonly onDisposed: Event<void>;
  readonly onRestarted: Event<void>;

src/client/datascience/notebook/helpers/executionHelpers.ts

@@ -5,6 +5,7 @@
 
 import type { nbformat } from '@jupyterlab/coreutils';
 import type { KernelMessage } from '@jupyterlab/services';
+import * as fastDeepEqual from 'fast-deep-equal';
 import { NotebookCell, NotebookCellRunState, NotebookDocument } from 'vscode';
 import { createErrorOutput } from '../../../../datascience-ui/common/cellFactory';
 import { createIOutputFromCellOutputs, createVSCCellOutputsFromOutputs, translateErrorOutput } from './helpers';
@@ -106,7 +107,7 @@ export function updateCellOutput(vscCell: NotebookCell, outputs: nbformat.IOutpu
  }
  // Compare outputs (at the end of the day everything is serializable).
  // Hence this is a safe comparison.
- if (vscCell.outputs.length === newOutput.length && JSON.stringify(vscCell.outputs) === JSON.stringify(newOutput)) {
+ if (vscCell.outputs.length === newOutput.length && fastDeepEqual(vscCell.outputs, newOutput)) {
  return;
  }
  vscCell.outputs = newOutput;

src/client/datascience/notebook/kernelProvider.ts

@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
+import * as fastDeepEqual from 'fast-deep-equal';
 import { inject, injectable } from 'inversify';
 import { CancellationToken, Event, EventEmitter } from 'vscode';
 import {
@@ -13,6 +14,7 @@ import { IVSCodeNotebook } from '../../common/application/types';
 import { createPromiseFromCancellation } from '../../common/cancellation';
 import { IDisposableRegistry } from '../../common/types';
 import { noop } from '../../common/utils/misc';
+import { KernelProvider } from '../jupyter/kernels/kernelProvider';
 import { KernelSelectionProvider } from '../jupyter/kernels/kernelSelections';
 import { KernelSelector } from '../jupyter/kernels/kernelSelector';
 import { KernelSwitcher } from '../jupyter/kernels/kernelSwitcher';
@@ -22,6 +24,7 @@ import { INotebook, INotebookProvider } from '../types';
 import { getNotebookMetadata, isJupyterNotebook, updateKernelInNotebookMetadata } from './helpers/helpers';
 import { NotebookKernel } from './notebookKernel';
 import { INotebookContentProvider, INotebookExecutionService } from './types';
+
 @injectable()
 export class VSCodeKernelPickerProvider implements NotebookKernelProvider {
  public get onDidChangeKernels(): Event<void> {
@@ -33,6 +36,7 @@ export class VSCodeKernelPickerProvider implements NotebookKernelProvider {
  @inject(INotebookExecutionService) private readonly execution: INotebookExecutionService,
  @inject(KernelSelectionProvider) private readonly kernelSelectionProvider: KernelSelectionProvider,
  @inject(KernelSelector) private readonly kernelSelector: KernelSelector,
+ @inject(KernelProvider) private readonly kernelProvider: KernelProvider,
  @inject(IVSCodeNotebook) private readonly notebook: IVSCodeNotebook,
  @inject(INotebookStorageProvider) private readonly storageProvider: INotebookStorageProvider,
  @inject(INotebookProvider) private readonly notebookProvider: INotebookProvider,
@@ -87,14 +91,14 @@ export class VSCodeKernelPickerProvider implements NotebookKernelProvider {
  if (
  preferredKernel.kernelSpec &&
  item.kernelSpec &&
- JSON.stringify(preferredKernel.kernelSpec) === JSON.stringify(item.kernelSpec)
+ fastDeepEqual(preferredKernel.kernelSpec, item.kernelSpec)
  ) {
  return true;
  }
  if (
  preferredKernel.kernelModel &&
  item.kernelModel &&
- JSON.stringify(preferredKernel.kernelModel) === JSON.stringify(item.kernelModel)
+ fastDeepEqual(preferredKernel.kernelModel, item.kernelModel)
  ) {
  return true;
  }
@@ -130,12 +134,23 @@ export class VSCodeKernelPickerProvider implements NotebookKernelProvider {
  // Possibly closed or different kernel picked.
  return;
  }
+
  const model = await this.storageProvider.getOrCreateModel(document.uri);
  if (!model || !model.isTrusted) {
  // If a model is not trusted, we cannot change the kernel (this results in changes to notebook metadata).
  // This is because we store selected kernel in the notebook metadata.
  return;
  }
+
+ // Check what the existing kernel is.
+ const existingKernel = this.kernelProvider.get(document.uri);
+ if (existingKernel && fastDeepEqual(existingKernel.metadata, newKernelInfo.kernel.selection)) {
+ return;
+ }
+
+ // Make this the new kernel (calling this method will associate the new kernel with this Uri).
+ this.kernelProvider.getOrCreate(document.uri, { metadata: newKernelInfo.kernel.selection });
+
  // Change kernel and update metadata.
  const notebook = await this.notebookProvider.getOrCreateNotebook({
  resource: document.uri,

src/client/datascience/notebook/notebookKernel.ts

@@ -57,7 +57,7 @@ export class NotebookKernel implements VSCNotebookKernel {
  constructor(
  public readonly label: string,
  public readonly description: string,
- private readonly selection: KernelSelection,
+ public readonly selection: Readonly<KernelSelection>,
  public readonly isPreferred: boolean,
  private readonly execution: INotebookExecutionService,
  private readonly kernelSelectionUsage: IKernelSelectionUsage