fix(linter): speed up inferred plugin node processing (#31281)

This PR improves the **createNodes** function of eslint's inferred
plugin by making two pragmatic choices:
- reusing the ESLint between config file's runs instead of recreating
the new one every time
- skipping ignored files checks for projects that already have eslint
config file

## Results of benchmarks on customer's repo:

### Without ESLint plugin
- create-project-graph-async - avg. 11739.1326225 -> 11 seconds
### With current ESLint plugin
- create-project-graph-async - avg. 98005.0965135 -> 98 seconds
### With modified ESLint plugin
- create-project-graph-async - avg. 13225.073817  -> 13 seconds
  - (@nx/eslint/plugin:createNodes - 2206.96497, 16.69%)


## Current Behavior
<!-- This is the behavior we have today -->

## Expected Behavior
<!-- This is the behavior we should expect with the changes in this PR
-->

## Related Issue(s)
<!-- Please link the issue being fixed so it gets closed when this is
merged. -->

Fixes #

packages/eslint/src/plugins/plugin.spec.ts

@@ -518,43 +518,45 @@ describe('@nx/eslint/plugin', () => {
       `);
     });
 
-    it('should not create nodes for nested projects without a root level eslint config when all files are ignored (.eslintignore)', async () => {
+    // This is intentionally disabled, since we should always create a node for project that contains eslint config
-      createFiles({
+    // it('should not create nodes for nested projects without a root level eslint config when all files are ignored (.eslintignore)', async () => {
-        'apps/my-app/.eslintrc.json': `{}`,
+    //   createFiles({
-        'apps/my-app/.eslintignore': `**/*`,
+    //     'apps/my-app/.eslintrc.json': `{}`,
-        'apps/my-app/project.json': `{}`,
+    //     'apps/my-app/.eslintignore': `**/*`,
-        'apps/my-app/index.ts': `console.log('hello world')`,
+    //     'apps/my-app/project.json': `{}`,
-        'libs/my-lib/.eslintrc.json': `{}`,
+    //     'apps/my-app/index.ts': `console.log('hello world')`,
-        'libs/my-lib/.eslintignore': `**/*`,
+    //     'libs/my-lib/.eslintrc.json': `{}`,
-        'libs/my-lib/project.json': `{}`,
+    //     'libs/my-lib/.eslintignore': `**/*`,
-        'libs/my-lib/index.ts': `console.log('hello world')`,
+    //     'libs/my-lib/project.json': `{}`,
-      });
+    //     'libs/my-lib/index.ts': `console.log('hello world')`,
-      expect(
+    //   });
-        await invokeCreateNodesOnMatchingFiles(context, { targetName: 'lint' })
+    //   expect(
-      ).toMatchInlineSnapshot(`
+    //     await invokeCreateNodesOnMatchingFiles(context, { targetName: 'lint' })
-        {
+    //   ).toMatchInlineSnapshot(`
-          "projects": {},
+    //     {
-        }
+    //       "projects": {},
-      `);
+    //     }
-    });
+    //   `);
+    // });
 
-    it('should not create nodes for nested projects without a root level eslint config when all files are ignored (ignorePatterns in .eslintrc.json)', async () => {
+    // This is intentionally disabled, since we should always create a node for project that contains eslint config
-      createFiles({
+    // it('should not create nodes for nested projects without a root level eslint config when all files are ignored (ignorePatterns in .eslintrc.json)', async () => {
-        'apps/my-app/.eslintrc.json': `{ "ignorePatterns": ["**/*"] }`,
+    //   createFiles({
-        'apps/my-app/project.json': `{}`,
+    //     'apps/my-app/.eslintrc.json': `{ "ignorePatterns": ["**/*"] }`,
-        'apps/my-app/index.ts': `console.log('hello world')`,
+    //     'apps/my-app/project.json': `{}`,
-        'libs/my-lib/.eslintrc.json': `{ "ignorePatterns": ["**/*"] }`,
+    //     'apps/my-app/index.ts': `console.log('hello world')`,
-        'libs/my-lib/project.json': `{}`,
+    //     'libs/my-lib/.eslintrc.json': `{ "ignorePatterns": ["**/*"] }`,
-        'libs/my-lib/index.ts': `console.log('hello world')`,
+    //     'libs/my-lib/project.json': `{}`,
-      });
+    //     'libs/my-lib/index.ts': `console.log('hello world')`,
-      expect(
+    //   });
-        await invokeCreateNodesOnMatchingFiles(context, { targetName: 'lint' })
+    //   expect(
-      ).toMatchInlineSnapshot(`
+    //     await invokeCreateNodesOnMatchingFiles(context, { targetName: 'lint' })
-        {
+    //   ).toMatchInlineSnapshot(`
-          "projects": {},
+    //     {
-        }
+    //       "projects": {},
-      `);
+    //     }
-    });
+    //   `);
+    // });
   });
 
   describe('root eslint config and nested eslint configs', () => {
@@ -721,7 +723,6 @@ describe('@nx/eslint/plugin', () => {
     it('should handle multiple levels of nesting and ignored files correctly', async () => {
       createFiles({
         '.eslintrc.json': '{ "root": true, "ignorePatterns": ["**/*"] }',
-        'apps/myapp/.eslintrc.json': '{ "extends": "../../.eslintrc.json" }', // no lintable files, don't create task
         'apps/myapp/project.json': '{}',
         'apps/myapp/index.ts': 'console.log("hello world")',
         'apps/myapp/nested/mylib/.eslintrc.json': JSON.stringify({

packages/eslint/src/plugins/plugin.ts

@@ -22,6 +22,7 @@ import { workspaceDataDirectory } from 'nx/src/utils/cache-directory';
 import { combineGlobPatterns } from 'nx/src/utils/globs';
 import { globWithWorkspaceContext } from 'nx/src/utils/workspace-context';
 import { gte } from 'semver';
+import type { ESLint as ESLintType } from 'eslint';
 import {
   baseEsLintConfigFile,
   BASE_ESLINT_CONFIG_FILENAMES,
@@ -186,6 +187,7 @@ const internalCreateNodes = async (
 };
 
 const internalCreateNodesV2 = async (
+  ESLint: typeof ESLintType,
   configFilePath: string,
   options: EslintPluginOptions,
   context: CreateNodesContextV2,
@@ -195,10 +197,6 @@ const internalCreateNodesV2 = async (
   hashByRoot: Map<string, string>
 ): Promise<CreateNodesResult> => {
   const configDir = dirname(configFilePath);
-
-  const ESLint = await resolveESLintClass({
-    useFlatConfigOverrideVal: isFlatConfig(configFilePath),
-  });
   const eslintVersion = ESLint.version;
 
   const projects: CreateNodesResult['projects'] = {};
@@ -212,15 +210,21 @@ const internalCreateNodesV2 = async (
         return;
       }
 
-      const eslint = new ESLint({
-        cwd: join(context.workspaceRoot, projectRoot),
-      });
       let hasNonIgnoredLintableFiles = false;
-      for (const file of lintableFilesPerProjectRoot.get(projectRoot) ?? []) {
+      if (configDir !== projectRoot || projectRoot === '.') {
-        if (!(await eslint.isPathIgnored(join(context.workspaceRoot, file)))) {
+        const eslint = new ESLint({
-          hasNonIgnoredLintableFiles = true;
+          cwd: join(context.workspaceRoot, projectRoot),
-          break;
+        });
+        for (const file of lintableFilesPerProjectRoot.get(projectRoot) ?? []) {
+          if (
+            !(await eslint.isPathIgnored(join(context.workspaceRoot, file)))
+          ) {
+            hasNonIgnoredLintableFiles = true;
+            break;
+          }
         }
+      } else {
+        hasNonIgnoredLintableFiles = true;
       }
 
       if (!hasNonIgnoredLintableFiles) {
@@ -286,9 +290,16 @@ export const createNodesV2: CreateNodesV2<EslintPluginOptions> = [
       projectRoots.map((r, i) => [r, hashes[i]])
     );
     try {
+      if (eslintConfigFiles.length === 0) {
+        return [];
+      }
+      const ESLint = await resolveESLintClass({
+        useFlatConfigOverrideVal: isFlatConfig(eslintConfigFiles[0]),
+      });
       return await createNodesFromFiles(
         (configFile, options, context) =>
           internalCreateNodesV2(
+            ESLint,
             configFile,
             options,
             context,