fix(linter): handle the flat config in workspace rule generators (nrwl#29253)

Closes nrwl#29252

## Current Behavior
See nrwl#29252

## Expected Behavior
See nrwl#29252

## Related Issue(s)
See nrwl#29252

Fixes #
See nrwl#29252

---------

Co-authored-by: Miroslav Jonaš <[email protected]>

Author: pawel-twardziak

packages/eslint/src/generators/workspace-rule/files/__name__.spec.ts__tmpl__

@@ -1,10 +1,19 @@
-import { TSESLint } from '@typescript-eslint/utils';
+<% if (flatConfig) { %>import { RuleTester } from '@typescript-eslint/rule-tester';
+import type { RuleTesterConfig } from '@typescript-eslint/rule-tester';
+import { rule, RULE_NAME } from './<%= name %>';
+
+const ruleTester = new RuleTester({
+  languageOptions: {
+    parser: require('@typescript-eslint/parser'),
+  },
+} as RuleTesterConfig);
+<% } else { %>import { TSESLint } from '@typescript-eslint/utils';
 import { rule, RULE_NAME } from './<%= name %>';
 
 const ruleTester = new TSESLint.RuleTester({
   parser: require.resolve('@typescript-eslint/parser'),
 });
-
+<% } %>
 ruleTester.run(RULE_NAME, rule, {
   valid: [`const example = true;`],
   invalid: [],

packages/eslint/src/generators/workspace-rule/workspace-rule.ts

@@ -1,18 +1,23 @@
 import {
+  addDependenciesToPackageJson,
   applyChangesToString,
   ChangeType,
   formatFiles,
   generateFiles,
+  GeneratorCallback,
   joinPathFragments,
   logger,
   readNxJson,
+  runTasksInSerial,
   Tree,
 } from '@nx/devkit';
 import { camelize } from '@nx/devkit/src/utils/string-utils';
 import { join } from 'path';
 import * as ts from 'typescript';
 import { workspaceLintPluginDir } from '../../utils/workspace-lint-rules';
 import { lintWorkspaceRulesProjectGenerator } from '../workspace-rules-project/workspace-rules-project';
+import { useFlatConfig } from '../../utils/flat-config';
+import { eslint9__typescriptESLintVersion } from '../../utils/versions';
 
 export interface LintWorkspaceRuleGeneratorOptions {
   name: string;
@@ -23,18 +28,31 @@ export async function lintWorkspaceRuleGenerator(
   tree: Tree,
   options: LintWorkspaceRuleGeneratorOptions
 ) {
+  const tasks: GeneratorCallback[] = [];
+
+  const flatConfig = useFlatConfig(tree);
+
   const nxJson = readNxJson(tree);
   // Ensure that the workspace rules project has been created
-  const projectGeneratorCallback = await lintWorkspaceRulesProjectGenerator(
-    tree,
-    {
+  tasks.push(
+    await lintWorkspaceRulesProjectGenerator(tree, {
       skipFormat: true,
       addPlugin:
         process.env.NX_ADD_PLUGINS !== 'false' &&
         nxJson.useInferencePlugins !== false,
-    }
+    })
   );
 
+  if (flatConfig) {
+    tasks.push(
+      addDependenciesToPackageJson(
+        tree,
+        {},
+        { '@typescript-eslint/rule-tester': eslint9__typescriptESLintVersion }
+      )
+    );
+  }
+
   const ruleDir = joinPathFragments(
     workspaceLintPluginDir,
     options.directory ?? ''
@@ -44,6 +62,7 @@ export async function lintWorkspaceRuleGenerator(
   generateFiles(tree, join(__dirname, 'files'), ruleDir, {
     tmpl: '',
     name: options.name,
+    flatConfig,
   });
 
   const nameCamelCase = camelize(options.name);
@@ -119,5 +138,5 @@ export async function lintWorkspaceRuleGenerator(
        }
 `);
 
-  return projectGeneratorCallback;
+  return runTasksInSerial(...tasks);
 }

packages/eslint/src/generators/workspace-rules-project/__snapshots__/workspace-rules-project.spec.ts.snap

@@ -81,6 +81,7 @@ exports[`@nx/eslint:workspace-rules-project should generate the required files 5
 "export default {
   displayName: 'eslint-rules',
   preset: '../../jest.preset.js',
+  testEnvironment: 'node',
   transform: {
     '^.+\\\\.[tj]s$': ['ts-jest', { tsconfig: '<rootDir>/tsconfig.spec.json' }],
   },

packages/eslint/src/generators/workspace-rules-project/workspace-rules-project.spec.ts

@@ -80,6 +80,7 @@ describe('@nx/eslint:workspace-rules-project', () => {
       "export default {
         displayName: 'eslint-rules',
         preset: '../../jest.preset.js',
+        testEnvironment: 'node',
         transform: {
           '^.+\\\\.[tj]s$': ['ts-jest', { tsconfig: '<rootDir>/tsconfig.spec.json' }],
         },
@@ -157,6 +158,7 @@ describe('@nx/eslint:workspace-rules-project', () => {
         export default {
           displayName: 'eslint-rules',
           preset: '../../jest.preset.js',
+          testEnvironment: 'node',
           transform: {
             '^.+\\\\.[tj]s$': ['@swc/jest', swcJestConfig],
           },

packages/eslint/src/generators/workspace-rules-project/workspace-rules-project.ts

@@ -83,6 +83,7 @@ export async function lintWorkspaceRulesProjectGenerator(
       setupFile: 'none',
       compiler: isUsingTsSolutionSetup(tree) ? 'swc' : 'tsc',
       skipFormat: true,
+      testEnvironment: 'node',
     })
   );