Clean up ESLint config (#5214)

Overview over changes:

- Allow the use of Node.js APIs in Node.js v18.0.0 and above
- Remove disabled rules that were too agressive (replace with inline
  ignore comments or fix lint errors)
- Scope mocha rules to only apply to test files
- Use modern style of extending imported flat config files
- Rename `package.json` script `lint-fix` to `lint:fix`
- Delete unused `.rslintrc.json` files
- Name all config groups (useful for debugging)

Author: watson

benchmark/sirun/appsec-iast/insecure-bank.js

@@ -1,5 +1,5 @@
 const http = require('http')
-const app = require('/opt/insecure-bank-js/app')
+const app = require('/opt/insecure-bank-js/app') // eslint-disable-line import/no-absolute-path
 
 const { port } = require('./common')
 

benchmark/sirun/appsec/insecure-bank.js

@@ -1,5 +1,5 @@
 const http = require('http')
-const app = require('/opt/insecure-bank-js/app')
+const app = require('/opt/insecure-bank-js/app') // eslint-disable-line import/no-absolute-path
 
 const { port } = require('./common')
 

eslint.config.mjs

@@ -1,19 +1,24 @@
-import mocha from 'eslint-plugin-mocha'
-import n from 'eslint-plugin-n'
-import stylistic from '@stylistic/eslint-plugin-js'
-import globals from 'globals'
 import path from 'node:path'
 import { fileURLToPath } from 'node:url'
-import js from '@eslint/js'
+
 import { FlatCompat } from '@eslint/eslintrc'
+import js from '@eslint/js'
+import stylistic from '@stylistic/eslint-plugin-js'
+import mocha from 'eslint-plugin-mocha'
+import n from 'eslint-plugin-n'
+import globals from 'globals'
 
 const __filename = fileURLToPath(import.meta.url)
 const __dirname = path.dirname(__filename)
-const compat = new FlatCompat({
-  baseDirectory: __dirname,
-  recommendedConfig: js.configs.recommended,
-  allConfig: js.configs.all
-})
+const compat = new FlatCompat({ baseDirectory: __dirname })
+
+const TEST_FILES = [
+  'packages/*/test/**/*.js',
+  'packages/*/test/**/*.mjs',
+  'integration-tests/**/*.js',
+  'integration-tests/**/*.mjs',
+  '**/*.spec.js'
+]
 
 export default [
   {
@@ -31,9 +36,13 @@ export default [
       'packages/dd-trace/src/appsec/blocked_templates.js', // TODO Why is this ignored?
       'packages/dd-trace/src/payload-tagging/jsonpath-plus.js' // Vendored
     ]
-  }, ...compat.extends('eslint:recommended', 'standard', 'plugin:mocha/recommended'), {
+  },
+  { name: '@eslint/js/recommnded', ...js.configs.recommended },
+  ...compat.extends('standard').map((config, i) => ({ name: config.name || `standard/${i + 1}`, ...config })),
+  {
+    name: 'dd-trace/defaults',
+
     plugins: {
-      mocha,
       n,
       '@stylistic/js': stylistic
     },
@@ -48,47 +57,43 @@ export default [
 
     settings: {
       node: {
-        version: '>=16.0.0'
+        // Used by `eslint-plugin-n` to determine the minimum version of Node.js to support.
+        // Normally setting this in the `package.json` engines field is enough, but when we have more than one active
+        // major release line at the same time, we need to specify the lowest version here to ensure backporting will
+        // not fail.
+        version: '>=18.0.0'
       }
     },
 
     rules: {
       '@stylistic/js/max-len': ['error', { code: 120, tabWidth: 2 }],
-      '@stylistic/js/object-curly-newline': ['error', {
-        multiline: true,
-        consistent: true
-      }],
+      '@stylistic/js/object-curly-newline': ['error', { multiline: true, consistent: true }],
       '@stylistic/js/object-curly-spacing': ['error', 'always'],
-      'import/no-absolute-path': 'off',
       'import/no-extraneous-dependencies': 'error',
-      'n/no-callback-literal': 'off',
       'n/no-restricted-require': ['error', ['diagnostics_channel']],
       'no-console': 'error',
-      'no-prototype-builtins': 'off',
-      'no-unused-expressions': 'off',
-      'no-var': 'error',
-      'prefer-const': 'error',
-      'standard/no-callback-literal': 'off'
+      'no-prototype-builtins': 'off', // Override (turned on by @eslint/js/recommnded)
+      'no-unused-expressions': 'off', // Override (turned on by standard)
+      'no-var': 'error' // Override (set to warn in standard)
     }
   },
   {
-    files: [
-      'packages/*/test/**/*.js',
-      'packages/*/test/**/*.mjs',
-      'integration-tests/**/*.js',
-      'integration-tests/**/*.mjs',
-      '**/*.spec.js'
-    ],
+    name: 'mocha/recommnded',
+    ...mocha.configs.flat.recommended,
+    files: TEST_FILES
+  },
+  {
+    name: 'dd-trace/tests/all',
+    files: TEST_FILES,
     languageOptions: {
       globals: {
-        ...globals.mocha,
-        sinon: false,
-        expect: false,
-        proxyquire: false,
-        withVersions: false,
-        withPeerService: false,
-        withNamingSchema: false,
-        withExports: false
+        sinon: 'readonly',
+        expect: 'readonly',
+        proxyquire: 'readonly',
+        withVersions: 'readonly',
+        withPeerService: 'readonly',
+        withNamingSchema: 'readonly',
+        withExports: 'readonly'
       }
     },
     rules: {
@@ -101,11 +106,11 @@ export default [
       'mocha/no-sibling-hooks': 'off',
       'mocha/no-skipped-tests': 'off',
       'mocha/no-top-level-hooks': 'off',
-      'n/handle-callback-err': 'off',
-      'no-loss-of-precision': 'off'
+      'n/handle-callback-err': 'off'
     }
   },
   {
+    name: 'dd-trace/tests/integration',
     files: [
       'integration-tests/**/*.js',
       'integration-tests/**/*.mjs',

integration-tests/.eslintrc.json

@@ -8,9 +8,9 @@ if (isMainThread) {
     throw e
   })
 } else {
-  function dummyOperation (a) {
-    return a + 'dummy operation with concat'
-  }
-
   dummyOperation('should not crash')
 }
+
+function dummyOperation (a) {
+  return a + 'dummy operation with concat'
+}

integration-tests/appsec/esm-app/worker.mjs

@@ -13,7 +13,7 @@
     "type:doc": "cd docs && yarn && yarn build",
     "type:test": "cd docs && yarn && yarn test",
     "lint": "node scripts/check_licenses.js && eslint . && yarn audit",
-    "lint-fix": "node scripts/check_licenses.js && eslint . --fix && yarn audit",
+    "lint:fix": "node scripts/check_licenses.js && eslint . --fix && yarn audit",
     "release:proposal": "node scripts/release/proposal",
     "services": "node ./scripts/install_plugin_modules && node packages/dd-trace/test/setup/services",
     "test": "SERVICES=* yarn services && mocha --expose-gc 'packages/dd-trace/test/setup/node.js' 'packages/*/test/**/*.spec.js'",
@@ -117,7 +117,7 @@
   "devDependencies": {
     "@apollo/server": "^4.11.0",
     "@eslint/eslintrc": "^3.1.0",
-    "@eslint/js": "^9.11.1",
+    "@eslint/js": "^8.57.1",
     "@msgpack/msgpack": "^3.0.0-beta3",
     "@stylistic/eslint-plugin-js": "^2.8.0",
     "@types/node": "^16.0.0",

package.json

@@ -113,14 +113,14 @@ describe('findScriptFromPartialPath', function () {
           })
         })
       })
-    })
 
-    function testPath (path) {
-      return function () {
-        const result = state.findScriptFromPartialPath(path)
-        expect(result).to.deep.equal([url, scriptId, undefined])
+      function testPath (path) {
+        return function () {
+          const result = state.findScriptFromPartialPath(path)
+          expect(result).to.deep.equal([url, scriptId, undefined])
+        }
       }
-    }
+    })
   }
 
   describe('multiple partial matches', function () {

packages/.eslintrc.json

@@ -35,7 +35,7 @@ describe('encode 0.5', () => {
         example: 1
       },
       start: 123123123123123120,
-      duration: 456456456456456456,
+      duration: 4564564564564564,
       links: []
     }]
   })