feat: Prompt to use the Ivy Language Service if VE is detected

In order to drive adoption of the new Ivy Language Service before it
becomes the default in v12, this commit adds a prompt for users to
enable it if they are using `@angular/core` v9+.

Fixes #1095

Author: atscott

client/src/client.ts

@@ -11,7 +11,7 @@ import * as path from 'path';
 import * as vscode from 'vscode';
 import * as lsp from 'vscode-languageclient/node';
 
-import {ProjectLoadingFinish, ProjectLoadingStart, SuggestStrictMode, SuggestStrictModeParams} from '../common/notifications';
+import {ProjectLoadingFinish, ProjectLoadingStart, SuggestIvyLanguageService, SuggestIvyLanguageServiceParams, SuggestStrictMode, SuggestStrictModeParams} from '../common/notifications';
 import {NgccProgress, NgccProgressToken, NgccProgressType} from '../common/progress';
 
 import {ProgressReporter} from './progress-reporter';
@@ -136,7 +136,26 @@ function registerNotificationHandlers(
         }
       });
 
-  context.subscriptions.push(disposable1, disposable2);
+  const disposable3 = client.onNotification(
+      SuggestIvyLanguageService, async (params: SuggestIvyLanguageServiceParams) => {
+        const config = vscode.workspace.getConfiguration();
+        if (config.get('angular.enable-experimental-ivy-prompt') === false) {
+          return;
+        }
+
+        const enableIvy = 'Enable';
+        const selection = await vscode.window.showInformationMessage(
+            params.message,
+            enableIvy,
+            'Ignore',
+        );
+        if (selection === enableIvy) {
+          config.update('angular.experimental-ivy', true);
+        }
+        config.update('angular.enable-experimental-ivy-prompt', false);
+      });
+
+  context.subscriptions.push(disposable1, disposable2, disposable3);
 }
 
 function registerProgressHandlers(client: lsp.LanguageClient, context: vscode.ExtensionContext) {

common/notifications.ts

@@ -26,3 +26,10 @@ export interface SuggestStrictModeParams {
 
 export const SuggestStrictMode =
     new NotificationType<SuggestStrictModeParams>('angular/suggestStrictMode');
+
+export interface SuggestIvyLanguageServiceParams {
+  message: string;
+}
+
+export const SuggestIvyLanguageService =
+    new NotificationType<SuggestIvyLanguageServiceParams>('angular/suggestIvyLanguageServiceMode');

integration/lsp/test_utils.ts

@@ -30,7 +30,7 @@ export function createConnection(serverOptions: ServerOptions): MessageConnectio
     '--tsProbeLocations',
     PACKAGE_ROOT,
     '--ngProbeLocations',
-    SERVER_PATH,
+    [SERVER_PATH, PROJECT_PATH].join(','),
   ];
   if (serverOptions.ivy) {
     argv.push('--experimental-ivy');

integration/lsp/viewengine_spec.ts

@@ -8,6 +8,7 @@
 
 import {MessageConnection} from 'vscode-jsonrpc';
 import * as lsp from 'vscode-languageserver-protocol';
+import {SuggestIvyLanguageService, SuggestIvyLanguageServiceParams} from '../../common/notifications';
 import {APP_COMPONENT, createConnection, FOO_TEMPLATE, initializeServer, openTextDocument} from './test_utils';
 
 describe('Angular language server', () => {
@@ -107,6 +108,12 @@ describe('Angular language server', () => {
     expect(diagnostics.length).toBe(1);
     expect(diagnostics[0].message).toContain(`Identifier 'doesnotexist' is not defined.`);
   });
+
+  it('should prompt to enable Ivy Language Service', async () => {
+    openTextDocument(client, APP_COMPONENT);
+    const message = await onSuggestIvyLanguageService(client);
+    expect(message).toContain('It is recommended that you enable the native Ivy Language Service');
+  });
 });
 
 describe('initialization', () => {
@@ -138,3 +145,11 @@ describe('initialization', () => {
     client.dispose();
   });
 });
+
+function onSuggestIvyLanguageService(client: MessageConnection): Promise<string> {
+  return new Promise(resolve => {
+    client.onNotification(SuggestIvyLanguageService, (params: SuggestIvyLanguageServiceParams) => {
+      resolve(params.message);
+    });
+  });
+}

package.json

@@ -57,6 +57,11 @@
           "default": false,
           "description": "This is an experimental feature that enables the Ivy language service."
         },
+        "angular.enable-experimental-ivy-prompt": {
+          "type": "boolean",
+          "default": true,
+          "description": "Prompt to enable the Ivy language service for the workspace when an old version is in use."
+        },
         "angular.trace.server": {
           "type": "string",
           "scope": "window",
@@ -159,4 +164,4 @@
     "type": "git",
     "url": "https://github.com/angular/vscode-ng-language-service"
   }
-}
+}

server/src/server.ts

@@ -10,7 +10,7 @@ import {generateHelpMessage, parseCommandLine} from './cmdline_utils';
 import {createLogger} from './logger';
 import {ServerHost} from './server_host';
 import {Session} from './session';
-import {resolveNgLangSvc, resolveTsServer} from './version_provider';
+import {resolveAngularCore, resolveNgLangSvc, resolveTsServer} from './version_provider';
 
 // Parse command line arguments
 const options = parseCommandLine(process.argv);
@@ -28,6 +28,7 @@ const logger = createLogger({
 
 const ts = resolveTsServer(options.tsProbeLocations);
 const ng = resolveNgLangSvc(options.ngProbeLocations, options.ivy);
+const angularCore = resolveAngularCore(options.ngProbeLocations);
 
 // ServerHost provides native OS functionality
 const host = new ServerHost();
@@ -40,6 +41,7 @@ const session = new Session({
   ngProbeLocation: ng.resolvedPath,
   ivy: options.ivy,
   logToConsole: options.logToConsole,
+  ngVersion: angularCore.version,
 });
 
 // Log initialization info

server/src/session.ts

@@ -10,20 +10,22 @@ import * as ts from 'typescript/lib/tsserverlibrary';
 import * as lsp from 'vscode-languageserver/node';
 
 import {ServerOptions} from '../common/initialize';
-import {ProjectLanguageService, ProjectLoadingFinish, ProjectLoadingStart, SuggestStrictMode} from '../common/notifications';
+import {ProjectLanguageService, ProjectLoadingFinish, ProjectLoadingStart, SuggestIvyLanguageService, SuggestStrictMode} from '../common/notifications';
 import {NgccProgressToken, NgccProgressType} from '../common/progress';
 
 import {readNgCompletionData, tsCompletionEntryToLspCompletionItem} from './completion';
 import {tsDiagnosticToLspDiagnostic} from './diagnostic';
 import {resolveAndRunNgcc} from './ngcc';
 import {ServerHost} from './server_host';
 import {filePathToUri, isConfiguredProject, lspPositionToTsPosition, lspRangeToTsPositions, tsTextSpanToLspRange, uriToFilePath} from './utils';
+import {Version} from './version_provider';
 
 export interface SessionOptions {
   host: ServerHost;
   logger: ts.server.Logger;
   ngPlugin: string;
   ngProbeLocation: string;
+  ngVersion: Version;
   ivy: boolean;
   logToConsole: boolean;
 }
@@ -44,6 +46,7 @@ export class Session {
   private readonly connection: lsp.Connection;
   private readonly projectService: ts.server.ProjectService;
   private readonly logger: ts.server.Logger;
+  private readonly angularCoreVersion: Version;
   private readonly ivy: boolean;
   private readonly configuredProjToExternalProj = new Map<string, string>();
   private readonly logToConsole: boolean;
@@ -54,6 +57,7 @@ export class Session {
     this.logger = options.logger;
     this.ivy = options.ivy;
     this.logToConsole = options.logToConsole;
+    this.angularCoreVersion = options.ngVersion;
     // Create a connection for the server. The connection uses Node's IPC as a transport.
     this.connection = lsp.createConnection();
     this.addProtocolHandlers(this.connection);
@@ -830,6 +834,12 @@ export class Session {
     } else {
       // Immediately enable Legacy/ViewEngine language service
       this.info(`Enabling VE language service for ${projectName}.`);
+      if (!this.ivy && this.angularCoreVersion.major >= 9) {
+        this.connection.sendNotification(SuggestIvyLanguageService, {
+          message: 'An old version of the Angular Language Service is enabled.' +
+              'It is recommended that you enable the native Ivy Language Service to get the latest features and bug fixes.',
+        });
+      }
     }
   }
 

server/src/version_provider.ts

@@ -89,6 +89,15 @@ export function resolveNgLangSvc(probeLocations: string[], ivy: boolean): NodeMo
   return resolveWithMinVersion(packageName, MIN_NG_VERSION, probeLocations, nglangsvc);
 }
 
+/**
+ * Resolve `@angular/core` from the given locations.
+ * @param probeLocations
+ */
+export function resolveAngularCore(probeLocations: string[]): NodeModule {
+  return resolveWithMinVersion(
+      '@angular/core/bundles/core.umd', '0.0', probeLocations, '@angular/core');
+}
+
 /**
  * Converts the specified string `a` to non-negative integer.
  * Returns -1 if the result is NaN.