feat(language-service): Add diagnostics to suggest turning on strict mode (#40423)

This PR adds a way for the language server to retrieve compiler options
diagnostics via `languageService.getCompilerOptionsDiagnostics()`.

This will be used by the language server to show a prompt in the editor if
users don't have `strict` or `fullTemplateTypeCheck` turned on.

Ref https://github.com/angular/vscode-ng-language-service/issues/1053

PR Close #40423

goldens/public-api/compiler-cli/error_code.d.ts

@@ -35,5 +35,6 @@ export declare enum ErrorCode {
     DUPLICATE_VARIABLE_DECLARATION = 8006,
     INLINE_TCB_REQUIRED = 8900,
     INLINE_TYPE_CTOR_REQUIRED = 8901,
-    INJECTABLE_DUPLICATE_PROV = 9001
+    INJECTABLE_DUPLICATE_PROV = 9001,
+    SUGGEST_STRICT_TEMPLATES = 10001
 }

packages/compiler-cli/src/ngtsc/core/api/src/public_options.ts

@@ -127,9 +127,9 @@ export interface StrictTemplateOptions {
   /**
    * If `true`, implies all template strictness flags below (unless individually disabled).
    *
-   * Has no effect unless `fullTemplateTypeCheck` is also enabled.
+   * This flag is a superset of `fullTemplateTypeCheck`.
    *
-   * Defaults to `false`, even if "fullTemplateTypeCheck" is set.
+   * Defaults to `false`, even if "fullTemplateTypeCheck" is `true`.
    */
   strictTemplates?: boolean;
 

packages/compiler-cli/src/ngtsc/core/src/compiler.ts

@@ -906,7 +906,7 @@ function getR3SymbolsFile(program: ts.Program): ts.SourceFile|null {
 
 /**
  * Since "strictTemplates" is a true superset of type checking capabilities compared to
- * "strictTemplateTypeCheck", it is required that the latter is not explicitly disabled if the
+ * "fullTemplateTypeCheck", it is required that the latter is not explicitly disabled if the
  * former is enabled.
  */
 function verifyCompatibleTypeCheckOptions(options: NgCompilerOptions): ts.Diagnostic|null {

packages/compiler-cli/src/ngtsc/diagnostics/src/error_code.ts

@@ -159,6 +159,16 @@ export enum ErrorCode {
    * An injectable already has a `ɵprov` property.
    */
   INJECTABLE_DUPLICATE_PROV = 9001,
+
+  // 10XXX error codes are reserved for diagnostics with category
+  // `ts.DiagnosticCategory.Suggestion`. These diagnostics are generated by
+  // language service.
+
+  /**
+   * Suggest users to enable `strictTemplates` to make use of full capabilities
+   * provided by Angular language service.
+   */
+  SUGGEST_STRICT_TEMPLATES = 10001,
 }
 
 /**

packages/language-service/ivy/BUILD.bazel

@@ -10,6 +10,7 @@ ts_library(
         "//packages/compiler-cli",
         "//packages/compiler-cli/src/ngtsc/core",
         "//packages/compiler-cli/src/ngtsc/core:api",
+        "//packages/compiler-cli/src/ngtsc/diagnostics",
         "//packages/compiler-cli/src/ngtsc/file_system",
         "//packages/compiler-cli/src/ngtsc/imports",
         "//packages/compiler-cli/src/ngtsc/incremental",

packages/language-service/ivy/language_service.ts

@@ -9,6 +9,7 @@
 import {AbsoluteSourceSpan, AST, ParseSourceSpan, TmplAstBoundEvent, TmplAstNode} from '@angular/compiler';
 import {CompilerOptions, ConfigurationHost, readConfiguration} from '@angular/compiler-cli';
 import {NgCompiler} from '@angular/compiler-cli/src/ngtsc/core';
+import {ErrorCode, ngErrorCode} from '@angular/compiler-cli/src/ngtsc/diagnostics';
 import {absoluteFrom, absoluteFromSourceFile, AbsoluteFsPath} from '@angular/compiler-cli/src/ngtsc/file_system';
 import {TypeCheckShimGenerator} from '@angular/compiler-cli/src/ngtsc/typecheck';
 import {OptimizeFor, TypeCheckingProgramStrategy} from '@angular/compiler-cli/src/ngtsc/typecheck/api';
@@ -50,7 +51,8 @@ export class LanguageService {
   private readonly adapter: LanguageServiceAdapter;
   private readonly parseConfigHost: LSParseConfigHost;
 
-  constructor(project: ts.server.Project, private readonly tsLS: ts.LanguageService) {
+  constructor(
+      private readonly project: ts.server.Project, private readonly tsLS: ts.LanguageService) {
     this.parseConfigHost = new LSParseConfigHost(project.projectService.host);
     this.options = parseNgCompilerOptions(project, this.parseConfigHost);
     logCompilerOptions(project, this.options);
@@ -268,6 +270,34 @@ export class LanguageService {
     return result;
   }
 
+  getCompilerOptionsDiagnostics(): ts.Diagnostic[] {
+    const project = this.project;
+    if (!(project instanceof ts.server.ConfiguredProject)) {
+      return [];
+    }
+
+    const diagnostics: ts.Diagnostic[] = [];
+    const configSourceFile = ts.readJsonConfigFile(
+        project.getConfigFilePath(), (path: string) => project.readFile(path));
+
+    if (!this.options.strictTemplates && !this.options.fullTemplateTypeCheck) {
+      diagnostics.push({
+        messageText: 'Some language features are not available. ' +
+            'To access all features, enable `strictTemplates` in `angularCompilerOptions`.',
+        category: ts.DiagnosticCategory.Suggestion,
+        code: ngErrorCode(ErrorCode.SUGGEST_STRICT_TEMPLATES),
+        file: configSourceFile,
+        start: undefined,
+        length: undefined,
+      });
+    }
+
+    const compiler = this.compilerFactory.getOrCreate();
+    diagnostics.push(...compiler.getOptionDiagnostics());
+
+    return diagnostics;
+  }
+
   private watchConfigFile(project: ts.server.Project) {
     // TODO: Check the case when the project is disposed. An InferredProject
     // could be disposed when a tsconfig.json is added to the workspace,

packages/language-service/ivy/test/legacy/BUILD.bazel

@@ -6,6 +6,8 @@ ts_library(
     srcs = glob(["*.ts"]),
     deps = [
         "//packages/compiler",
+        "//packages/compiler-cli/src/ngtsc/core:api",
+        "//packages/compiler-cli/src/ngtsc/diagnostics",
         "//packages/language-service/ivy",
         "@npm//typescript",
     ],

packages/language-service/ivy/test/legacy/language_service_spec.ts

@@ -6,6 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
+import {ErrorCode, ngErrorCode} from '@angular/compiler-cli/src/ngtsc/diagnostics';
 import * as ts from 'typescript/lib/tsserverlibrary';
 
 import {LanguageService} from '../../language_service';
@@ -31,15 +32,6 @@ describe('language service adapter', () => {
   });
 
   describe('parse compiler options', () => {
-    beforeEach(() => {
-      // Need to reset project on each test to reinitialize file watchers.
-      const {project: _project, tsLS, service: _service, configFileFs: _configFileFs} = setup();
-      project = _project;
-      service = _service;
-      configFileFs = _configFileFs;
-      ngLS = new LanguageService(project, tsLS);
-    });
-
     it('should initialize with angularCompilerOptions from tsconfig.json', () => {
       expect(ngLS.getCompilerOptions()).toEqual(jasmine.objectContaining({
         enableIvy: true,  // default for ivy is true
@@ -55,11 +47,11 @@ describe('language service adapter', () => {
         strictInjectionParameters: true,
       }));
 
-      configFileFs.overwriteConfigFile(TSCONFIG, `{
-         "angularCompilerOptions": {
-           "strictTemplates": false
-         }
-       }`);
+      configFileFs.overwriteConfigFile(TSCONFIG, {
+        angularCompilerOptions: {
+          strictTemplates: false,
+        }
+      });
 
       expect(ngLS.getCompilerOptions()).toEqual(jasmine.objectContaining({
         strictTemplates: false,
@@ -67,6 +59,44 @@ describe('language service adapter', () => {
     });
   });
 
+  describe('compiler options diagnostics', () => {
+    it('suggests turning on strict flag', () => {
+      configFileFs.overwriteConfigFile(TSCONFIG, {
+        angularCompilerOptions: {},
+      });
+      const diags = ngLS.getCompilerOptionsDiagnostics();
+      const diag = diags.find(isSuggestStrictTemplatesDiag);
+      expect(diag).toBeDefined();
+      expect(diag!.category).toBe(ts.DiagnosticCategory.Suggestion);
+      expect(diag!.file?.getSourceFile().fileName).toBe(TSCONFIG);
+    });
+
+    it('does not suggest turning on strict mode is strictTemplates flag is on', () => {
+      configFileFs.overwriteConfigFile(TSCONFIG, {
+        angularCompilerOptions: {
+          strictTemplates: true,
+        },
+      });
+      const diags = ngLS.getCompilerOptionsDiagnostics();
+      const diag = diags.find(isSuggestStrictTemplatesDiag);
+      expect(diag).toBeUndefined();
+    });
+
+    it('does not suggest turning on strict mode is fullTemplateTypeCheck flag is on', () => {
+      configFileFs.overwriteConfigFile(TSCONFIG, {
+        angularCompilerOptions: {
+          fullTemplateTypeCheck: true,
+        },
+      });
+      const diags = ngLS.getCompilerOptionsDiagnostics();
+      const diag = diags.find(isSuggestStrictTemplatesDiag);
+      expect(diag).toBeUndefined();
+    });
+
+    function isSuggestStrictTemplatesDiag(diag: ts.Diagnostic) {
+      return diag.code === ngErrorCode(ErrorCode.SUGGEST_STRICT_TEMPLATES);
+    }
+  });
 
   describe('last known program', () => {
     beforeEach(() => {

packages/language-service/ivy/test/legacy/mock_host.ts

@@ -6,6 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
+import {NgCompilerOptions} from '@angular/compiler-cli/src/ngtsc/core/api';
 import {join} from 'path';
 import * as ts from 'typescript/lib/tsserverlibrary';
 
@@ -68,11 +69,11 @@ export class MockConfigFileFs implements
   private configOverwrites = new Map<string, string>();
   private configFileWatchers = new Map<string, MockWatcher>();
 
-  overwriteConfigFile(configFile: string, contents: string) {
+  overwriteConfigFile(configFile: string, contents: {angularCompilerOptions?: NgCompilerOptions}) {
     if (!configFile.endsWith('.json')) {
       throw new Error(`${configFile} is not a configuration file.`);
     }
-    this.configOverwrites.set(configFile, contents);
+    this.configOverwrites.set(configFile, JSON.stringify(contents));
     this.configFileWatchers.get(configFile)?.changed();
   }
 
@@ -98,8 +99,11 @@ export class MockConfigFileFs implements
   }
 
   clear() {
+    for (const [fileName, watcher] of this.configFileWatchers) {
+      this.configOverwrites.delete(fileName);
+      watcher.changed();
+    }
     this.configOverwrites.clear();
-    this.configFileWatchers.clear();
   }
 }
 

packages/language-service/ivy/ts_plugin.ts

@@ -119,6 +119,17 @@ export function create(info: ts.server.PluginCreateInfo): NgLanguageService {
           ngLS.getCompletionEntrySymbol(fileName, position, name);
     }
   }
+  /**
+   * Gets global diagnostics related to the program configuration and compiler options.
+   */
+  function getCompilerOptionsDiagnostics(): ts.Diagnostic[] {
+    const diagnostics: ts.Diagnostic[] = [];
+    if (!angularOnly) {
+      diagnostics.push(...tsLS.getCompilerOptionsDiagnostics());
+    }
+    diagnostics.push(...ngLS.getCompilerOptionsDiagnostics());
+    return diagnostics;
+  }
 
   function getTcb(fileName: string, position: number): GetTcbResponse {
     return ngLS.getTcb(fileName, position);
@@ -137,6 +148,7 @@ export function create(info: ts.server.PluginCreateInfo): NgLanguageService {
     getCompletionEntryDetails,
     getCompletionEntrySymbol,
     getTcb,
+    getCompilerOptionsDiagnostics,
   };
 }