feat(typescript-estree): add EXPERIMENTAL_useProjectService option to use TypeScript project service

.github/workflows/ci.yml

@@ -193,6 +193,38 @@ jobs:
           # Sadly 1 day is the minimum
           retention-days: 1
 
+  unit_tests_tsserver:
+    name: Run Unit Tests with Experimental TSServer
+    needs: [build]
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        package:
+          [
+            'eslint-plugin',
+            'eslint-plugin-internal',
+            'eslint-plugin-tslint',
+            'typescript-estree',
+          ]
+    env:
+      COLLECT_COVERAGE: false
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 2
+      - name: Install
+        uses: ./.github/actions/prepare-install
+        with:
+          node-version: 18
+      - name: Build
+        uses: ./.github/actions/prepare-build
+      - name: Run unit tests for ${{ matrix.package }}
+        run: npx nx test ${{ matrix.package }} --coverage=false
+        env:
+          CI: true
+          TYPESCRIPT_ESLINT_EXPERIMENTAL_TSSERVER: true
+
   website_tests:
     # The NETLIFY_TOKEN secret will not be available on forks
     if: github.repository_owner == 'typescript-eslint'

.vscode/launch.json

@@ -141,6 +141,40 @@
         "${workspaceFolder}/packages/scope-manager/dist/index.js",
       ],
     },
+    {
+      "type": "node",
+      "request": "launch",
+      "name": "Jest Test Current eslint-plugin-tslint Rule",
+      "cwd": "${workspaceFolder}/packages/eslint-plugin-tslint/",
+      "program": "${workspaceFolder}/node_modules/jest/bin/jest.js",
+      "args": [
+        "--runInBand",
+        "--no-cache",
+        "--no-coverage",
+        "${fileBasenameNoExtension}"
+      ],
+      "sourceMaps": true,
+      "console": "integratedTerminal",
+      "internalConsoleOptions": "neverOpen",
+      "skipFiles": [
+        "${workspaceFolder}/packages/utils/src/index.ts",
+        "${workspaceFolder}/packages/utils/dist/index.js",
+        "${workspaceFolder}/packages/utils/src/ts-estree.ts",
+        "${workspaceFolder}/packages/utils/dist/ts-estree.js",
+        "${workspaceFolder}/packages/type-utils/src/index.ts",
+        "${workspaceFolder}/packages/type-utils/dist/index.js",
+        "${workspaceFolder}/packages/parser/src/index.ts",
+        "${workspaceFolder}/packages/parser/dist/index.js",
+        "${workspaceFolder}/packages/typescript-estree/src/index.ts",
+        "${workspaceFolder}/packages/typescript-estree/dist/index.js",
+        "${workspaceFolder}/packages/types/src/index.ts",
+        "${workspaceFolder}/packages/types/dist/index.js",
+        "${workspaceFolder}/packages/visitor-keys/src/index.ts",
+        "${workspaceFolder}/packages/visitor-keys/dist/index.js",
+        "${workspaceFolder}/packages/scope-manager/dist/index.js",
+        "${workspaceFolder}/packages/scope-manager/dist/index.js",
+      ],
+    },
     {
       "type": "node",
       "request": "launch",

docs/packages/TypeScript_ESTree.mdx

@@ -147,6 +147,15 @@ interface ParseAndGenerateServicesOptions extends ParseOptions {
    */
   errorOnTypeScriptSyntacticAndSemanticIssues?: boolean;
 
+  /**
+   * ***EXPERIMENTAL FLAG*** - Use this at your own risk.
+   *
+   * Whether to create a shared TypeScript server to power program creation.
+   *
+   * @see https://github.com/typescript-eslint/typescript-eslint/issues/6575
+   */
+  EXPERIMENTAL_useProjectService?: boolean;
+
   /**
    * ***EXPERIMENTAL FLAG*** - Use this at your own risk.
    *
@@ -155,7 +164,7 @@ interface ParseAndGenerateServicesOptions extends ParseOptions {
    *
    * This flag REQUIRES at least TS v3.9, otherwise it does nothing.
    *
-   * See: https://github.com/typescript-eslint/typescript-eslint/issues/2094
+   * @see https://github.com/typescript-eslint/typescript-eslint/issues/2094
    */
   EXPERIMENTAL_useSourceOfProjectReferenceRedirect?: boolean;
 

packages/eslint-plugin-tslint/src/rules/config.ts

@@ -1,4 +1,5 @@
 import { ESLintUtils } from '@typescript-eslint/utils';
+import path from 'path';
 import type { RuleSeverity } from 'tslint';
 import { Configuration } from 'tslint';
 
@@ -118,7 +119,7 @@ export default createRule<Options, MessageIds>({
     context,
     [{ rules: tslintRules, rulesDirectory: tslintRulesDirectory, lintFile }],
   ) {
-    const fileName = context.getFilename();
+    const fileName = path.resolve(context.getCwd(), context.getFilename());
     const sourceCode = context.getSourceCode().text;
     const services = ESLintUtils.getParserServices(context);
     const program = services.program;

packages/eslint-plugin/tests/rules/consistent-type-imports.test.ts

@@ -16,6 +16,7 @@ const ruleTester = new RuleTester({
 });
 
 const withMetaParserOptions = {
+  EXPERIMENTAL_useProjectService: false,
   tsconfigRootDir: getFixturesRootDir(),
   project: './tsconfig-withmeta.json',
 };

packages/eslint-plugin/tests/rules/no-unnecessary-condition.test.ts

@@ -595,6 +595,7 @@ function getElem(dict: Record<string, { foo: string }>, key: string) {
 }
       `,
       parserOptions: {
+        EXPERIMENTAL_useProjectService: false,
         tsconfigRootDir: getFixturesRootDir(),
         project: './tsconfig.noUncheckedIndexedAccess.json',
       },

packages/eslint-plugin/tests/rules/no-unsafe-assignment.test.ts

@@ -65,6 +65,7 @@ function assignmentTest(
 const ruleTester = new RuleTester({
   parser: '@typescript-eslint/parser',
   parserOptions: {
+    EXPERIMENTAL_useProjectService: false,
     project: './tsconfig.noImplicitThis.json',
     tsconfigRootDir: getFixturesRootDir(),
   },

packages/eslint-plugin/tests/rules/no-unsafe-call.test.ts

@@ -6,6 +6,7 @@ import { getFixturesRootDir } from '../RuleTester';
 const ruleTester = new RuleTester({
   parser: '@typescript-eslint/parser',
   parserOptions: {
+    EXPERIMENTAL_useProjectService: false,
     project: './tsconfig.noImplicitThis.json',
     tsconfigRootDir: getFixturesRootDir(),
   },

packages/eslint-plugin/tests/rules/no-unsafe-member-access.test.ts

@@ -6,6 +6,7 @@ import { getFixturesRootDir } from '../RuleTester';
 const ruleTester = new RuleTester({
   parser: '@typescript-eslint/parser',
   parserOptions: {
+    EXPERIMENTAL_useProjectService: false,
     project: './tsconfig.noImplicitThis.json',
     tsconfigRootDir: getFixturesRootDir(),
   },

packages/eslint-plugin/tests/rules/no-unsafe-return.test.ts

@@ -6,6 +6,7 @@ import { getFixturesRootDir } from '../RuleTester';
 const ruleTester = new RuleTester({
   parser: '@typescript-eslint/parser',
   parserOptions: {
+    EXPERIMENTAL_useProjectService: false,
     project: './tsconfig.noImplicitThis.json',
     tsconfigRootDir: getFixturesRootDir(),
   },

packages/eslint-plugin/tests/rules/no-unused-vars/no-unused-vars.test.ts

@@ -14,6 +14,7 @@ const ruleTester = new RuleTester({
 });
 
 const withMetaParserOptions = {
+  EXPERIMENTAL_useProjectService: false,
   tsconfigRootDir: getFixturesRootDir(),
   project: './tsconfig-withmeta.json',
 };

packages/eslint-plugin/tests/rules/non-nullable-type-assertion-style.test.ts

@@ -204,6 +204,7 @@ const y = x!;
 
 const ruleTesterWithNoUncheckedIndexAccess = new RuleTester({
   parserOptions: {
+    EXPERIMENTAL_useProjectService: false,
     sourceType: 'module',
     tsconfigRootDir: getFixturesRootDir(),
     project: './tsconfig.noUncheckedIndexedAccess.json',

packages/parser/tests/lib/parser.ts

@@ -1,6 +1,7 @@
 import * as scopeManager from '@typescript-eslint/scope-manager';
 import type { ParserOptions } from '@typescript-eslint/types';
 import * as typescriptESTree from '@typescript-eslint/typescript-estree';
+import path from 'path';
 
 import { parse, parseForESLint } from '../../src/parser';
 
@@ -33,10 +34,10 @@ describe('parser', () => {
         jsx: false,
       },
       // ts-estree specific
-      filePath: 'isolated-file.src.ts',
+      filePath: './isolated-file.src.ts',
       project: 'tsconfig.json',
       errorOnTypeScriptSyntacticAndSemanticIssues: false,
-      tsconfigRootDir: 'tests/fixtures/services',
+      tsconfigRootDir: path.resolve(__dirname, '../fixtures/services'),
       extraFileExtensions: ['.foo'],
     };
     parseForESLint(code, config);
@@ -89,7 +90,7 @@ describe('parser', () => {
       filePath: 'isolated-file.src.ts',
       project: 'tsconfig.json',
       errorOnTypeScriptSyntacticAndSemanticIssues: false,
-      tsconfigRootDir: 'tests/fixtures/services',
+      tsconfigRootDir: path.join(__dirname, '../fixtures/services'),
       extraFileExtensions: ['.foo'],
     };
     parseForESLint(code, config);

packages/rule-tester/tests/RuleTester.test.ts

@@ -169,6 +169,7 @@ describe('RuleTester', () => {
           {
             code: 'type-aware parser options should override the constructor config',
             parserOptions: {
+              EXPERIMENTAL_useProjectService: false,
               project: 'tsconfig.test-specific.json',
               tsconfigRootDir: '/set/in/the/test/',
             },
@@ -209,6 +210,7 @@ describe('RuleTester', () => {
             "code": "type-aware parser options should override the constructor config",
             "filename": "/set/in/the/test/file.ts",
             "parserOptions": {
+              "EXPERIMENTAL_useProjectService": false,
               "project": "tsconfig.test-specific.json",
               "tsconfigRootDir": "/set/in/the/test/",
             },

packages/type-utils/tests/TypeOrValueSpecifier.test.ts

@@ -196,42 +196,42 @@ describe('TypeOrValueSpecifier', () => {
       ],
       [
         'interface Foo {prop: string}; type Test = Foo;',
-        { from: 'file', name: 'Foo', path: 'tests/fixtures/file.ts' },
+        { from: 'file', name: 'Foo', path: 'file.ts' },
       ],
       [
         'type Foo = {prop: string}; type Test = Foo;',
-        { from: 'file', name: 'Foo', path: 'tests/fixtures/file.ts' },
+        { from: 'file', name: 'Foo', path: 'file.ts' },
       ],
       [
         'interface Foo {prop: string}; type Test = Foo;',
         {
           from: 'file',
           name: 'Foo',
-          path: 'tests/../tests/fixtures/////file.ts',
+          path: './////file.ts',
         },
       ],
       [
         'type Foo = {prop: string}; type Test = Foo;',
         {
           from: 'file',
           name: 'Foo',
-          path: 'tests/../tests/fixtures/////file.ts',
+          path: './////file.ts',
         },
       ],
       [
         'interface Foo {prop: string}; type Test = Foo;',
         {
           from: 'file',
           name: ['Foo', 'Bar'],
-          path: 'tests/fixtures/file.ts',
+          path: 'file.ts',
         },
       ],
       [
         'type Foo = {prop: string}; type Test = Foo;',
         {
           from: 'file',
           name: ['Foo', 'Bar'],
-          path: 'tests/fixtures/file.ts',
+          path: 'file.ts',
         },
       ],
     ])('matches a matching file specifier: %s', runTestPositive);
@@ -247,14 +247,14 @@ describe('TypeOrValueSpecifier', () => {
       ],
       [
         'interface Foo {prop: string}; type Test = Foo;',
-        { from: 'file', name: 'Foo', path: 'tests/fixtures/wrong-file.ts' },
+        { from: 'file', name: 'Foo', path: 'wrong-file.ts' },
       ],
       [
         'interface Foo {prop: string}; type Test = Foo;',
         {
           from: 'file',
           name: ['Foo', 'Bar'],
-          path: 'tests/fixtures/wrong-file.ts',
+          path: 'wrong-file.ts',
         },
       ],
     ])("doesn't match a mismatched file specifier: %s", runTestNegative);
@@ -399,14 +399,14 @@ describe('TypeOrValueSpecifier', () => {
       ['type Test = RegExp;', { from: 'file', name: ['RegExp', 'BigInt'] }],
       [
         'type Test = RegExp;',
-        { from: 'file', name: 'RegExp', path: 'tests/fixtures/file.ts' },
+        { from: 'file', name: 'RegExp', path: 'file.ts' },
       ],
       [
         'type Test = RegExp;',
         {
           from: 'file',
           name: ['RegExp', 'BigInt'],
-          path: 'tests/fixtures/file.ts',
+          path: 'file.ts',
         },
       ],
       [

packages/types/src/parser-options.ts

@@ -47,6 +47,7 @@ interface ParserOptions {
   debugLevel?: DebugLevel;
   errorOnTypeScriptSyntacticAndSemanticIssues?: boolean;
   errorOnUnknownASTType?: boolean;
+  EXPERIMENTAL_useProjectService?: boolean; // purposely undocumented for now
   EXPERIMENTAL_useSourceOfProjectReferenceRedirect?: boolean; // purposely undocumented for now
   extraFileExtensions?: string[];
   filePath?: string;

packages/typescript-estree/src/clear-caches.ts

@@ -1,6 +1,9 @@
 import { clearWatchCaches } from './create-program/getWatchProgramsForProjects';
 import { clearProgramCache as clearProgramCacheOriginal } from './parser';
-import { clearTSConfigMatchCache } from './parseSettings/createParseSettings';
+import {
+  clearTSConfigMatchCache,
+  clearTSServerProjectService,
+} from './parseSettings/createParseSettings';
 import { clearGlobCache } from './parseSettings/resolveProjectList';
 
 /**
@@ -14,6 +17,7 @@ export function clearCaches(): void {
   clearProgramCacheOriginal();
   clearWatchCaches();
   clearTSConfigMatchCache();
+  clearTSServerProjectService();
   clearGlobCache();
 }
 

packages/typescript-estree/src/create-program/createProjectProgram.ts

@@ -5,7 +5,6 @@ import * as ts from 'typescript';
 import { firstDefined } from '../node-utils';
 import type { ParseSettings } from '../parseSettings';
 import { describeFilePath } from './describeFilePath';
-import { getWatchProgramsForProjects } from './getWatchProgramsForProjects';
 import type { ASTAndDefiniteProgram } from './shared';
 import { getAstFromProgram } from './shared';
 
@@ -28,12 +27,12 @@ const DEFAULT_EXTRA_FILE_EXTENSIONS = [
  */
 function createProjectProgram(
   parseSettings: ParseSettings,
+  programsForProjects: readonly ts.Program[],
 ): ASTAndDefiniteProgram | undefined {
   log('Creating project program for: %s', parseSettings.filePath);
 
-  const programsForProjects = getWatchProgramsForProjects(parseSettings);
   const astAndProgram = firstDefined(programsForProjects, currentProgram =>
-    getAstFromProgram(currentProgram, parseSettings),
+    getAstFromProgram(currentProgram, parseSettings.filePath),
   );
 
   // The file was either matched within the tsconfig, or we allow creating a default program