fix: regression for eslint v6

.prettierignore

@@ -3,7 +3,6 @@
 **/dist
 **/coverage
 **/shared-fixtures
-**/tests/integration/fixtures/**/*
 **/.vscode
 **/.nyc_output
 packages/eslint-plugin-tslint/tests/test-tslint-rules-directory/alwaysFailRule.js

packages/experimental-utils/src/ts-eslint/ESLint.ts

@@ -341,6 +341,16 @@ namespace ESLint {
   }
 }
 
+// We want to export this class always so it's easy for end users to consume.
+// However on ESLint v6, this class will not exist, so we provide a fallback to make it clear
+// The only users of this should be users scripting ESLint locally, so _they_ should have the correct version installed.
+const _ESLint = (ESLintESLint ??
+  function (): void {
+    throw new Error(
+      'Attempted to construct an ESLint instance on less than ESLint v7.0.0',
+    );
+  }) as typeof ESLintBase;
+
 /**
  * The ESLint class is the primary class to use in Node.js applications.
  * This class depends on the Node.js fs module and the file system, so you cannot use it in browsers.
@@ -349,6 +359,6 @@ namespace ESLint {
  *
  * @since 7.0.0
  */
-class ESLint extends (ESLintESLint as typeof ESLintBase) {}
+class ESLint extends _ESLint {}
 
 export { ESLint };

tests/integration/README.md

@@ -16,3 +16,5 @@ These tests are setup to run within docker containers to ensure that each test i
 1. Add a new entry to `run-all-tests.sh` by copy+pasting an existing command, and changing the name to match your new folder.
 1. Run your integration test by running the single command you copied in the previous step.
    - If your test finishes successfully, a `test.js.snap` will be created.
+
+If you run your test and see the test fail with `Cannot find module './lint-output.json' from 'test.js'`, this means that ESLint errored whilst attempting to run the lint command.

tests/integration/docker-compose.yml

@@ -97,3 +97,22 @@ services:
       - /usr/eslint-plugin/tests
       # Runtime link to all the specific integration test files, so that most updates don't require a rebuild.
       - ./fixtures/markdown:/usr/linked
+
+  eslint-v6:
+    build: ./fixtures/eslint-v6
+    container_name: 'eslint-v6'
+    volumes:
+      # Runtime link to the relevant built @typescript-eslint packages and integration test utils,
+      # but apply an empty volume for the package tests, we don't need those.
+      - ../../package.json/:/usr/root-package.json
+      - ./utils/:/usr/utils
+      - ../../packages/parser/:/usr/parser
+      - /usr/parser/tests
+      - ../../packages/typescript-estree/:/usr/typescript-estree
+      - /usr/typescript-estree/tests
+      - ../../packages/experimental-utils/:/usr/experimental-utils
+      - /usr/experimental-utils/tests
+      - ../../packages/eslint-plugin/:/usr/eslint-plugin
+      - /usr/eslint-plugin/tests
+      # Runtime link to all the specific integration test files, so that most updates don't require a rebuild.
+      - ./fixtures/eslint-v6:/usr/linked

tests/integration/fixtures/eslint-v6/.eslintrc.js

@@ -0,0 +1,12 @@
+module.exports = {
+  root: true,
+  // Local version of @typescript-eslint/parser
+  parser: '@typescript-eslint/parser',
+  plugins: [
+    // Local version of @typescript-eslint/eslint-plugin
+    '@typescript-eslint',
+  ],
+  rules: {
+    '@typescript-eslint/no-explicit-any': 'error',
+  },
+};

tests/integration/fixtures/eslint-v6/Dockerfile

@@ -0,0 +1,17 @@
+FROM node:erbium
+
+# Copy the test.sh into the container. Every other file will be linked, rather
+# than copied to allow for changes without rebuilds wherever possible
+WORKDIR /usr
+COPY ./test.sh /usr/
+
+# Create file which will be executed by jest
+# to assert that the lint output is what we expect
+RUN echo "const actualLintOutput = require('./lint-output.json');\n" \
+    "\n" \
+    "test('it should produce the expected lint ouput', () => {\n" \
+    "  expect(actualLintOutput).toMatchSnapshot();\n" \
+    "});\n" > test.js
+
+# Run the integration test
+CMD [ "./test.sh" ]

tests/integration/fixtures/eslint-v6/index.ts

@@ -0,0 +1 @@
+const noSemi: any = true;

tests/integration/fixtures/eslint-v6/test.js.snap

@@ -0,0 +1,28 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`it should produce the expected lint ouput 1`] = `
+Array [
+  Object {
+    "errorCount": 1,
+    "filePath": "/usr/linked/index.ts",
+    "fixableErrorCount": 0,
+    "fixableWarningCount": 0,
+    "messages": Array [
+      Object {
+        "column": 15,
+        "endColumn": 18,
+        "endLine": 1,
+        "line": 1,
+        "message": "Unexpected any. Specify a different type.",
+        "messageId": "unexpectedAny",
+        "nodeType": "TSAnyKeyword",
+        "ruleId": "@typescript-eslint/no-explicit-any",
+        "severity": 2,
+      },
+    ],
+    "source": "const noSemi: any = true;
+",
+    "warningCount": 0,
+  },
+]
+`;

tests/integration/fixtures/eslint-v6/test.sh

@@ -0,0 +1,22 @@
+#!/bin/bash
+set -exuo pipefail
+
+# Generate the package.json to use
+node /usr/utils/generate-package-json.js
+
+# Install dependencies
+npm install
+npm install eslint@6.0.0
+
+# Use the local volumes for our own packages
+npm install $(npm pack /usr/typescript-estree | tail -1)
+npm install $(npm pack /usr/parser | tail -1)
+npm install $(npm pack /usr/experimental-utils | tail -1)
+npm install $(npm pack /usr/eslint-plugin | tail -1)
+
+# Run the linting
+# (the "|| true" helps make sure that we run our tests on failed linting runs as well)
+npx eslint --format json --output-file /usr/lint-output.json --config /usr/linked/.eslintrc.js /usr/linked/**/*.ts || true
+
+# Run our assertions against the linting output
+npx jest /usr/test.js --snapshotResolver=/usr/utils/jest-snapshot-resolver.js

tests/integration/fixtures/eslint-v6/tsconfig.json

@@ -0,0 +1,5 @@
+{
+  "compilerOptions": {
+    "strict": true
+  }
+}

tests/integration/fixtures/markdown/Doc.md

@@ -1,6 +1,7 @@
 Some extra text to verify that the markdown plugin is ignoring anything that is not a code block.
 
 expected no-console error:
+
 ```jsx
 import { Button } from 'antd';
 
@@ -20,6 +21,7 @@ function MyComp() {
 
 expected no-explicit-any error:
 expected no-console error:
+
 ```jsx
 import { Button } from 'antd';
 
@@ -38,6 +40,7 @@ function MyComp(): any {
 ```
 
 expected no-console error:
+
 ```js
 function foo() {
   console.log('test');
@@ -46,24 +49,25 @@ function foo() {
 
 expected no-explicit-any error:
 expected no-console error:
+
 ```js
 function foo(): any {
   console.log('test');
 }
 ```
 
-
 expected no-explicit-any error:
 expected no-console error:
+
 ```javascript
 function foo(): any {
   console.log('test');
 }
 ```
 
-
 expected no-explicit-any error:
 expected no-console error:
+
 ```node
 function foo(): any {
   console.log('test');