chore: add regression testing against old TS and ESLint versions

.eslintrc.js

@@ -26,6 +26,7 @@ module.exports = {
       './tsconfig.eslint.json',
       './packages/*/tsconfig.json',
       './tests/integration/tsconfig.json',
+      './tools/tsconfig.json',
       /**
        * We are currently in the process of transitioning to nx's out of the box structure and
        * so need to manually specify converted packages' tsconfig.build.json and tsconfig.spec.json

.github/workflows/ci.yml

@@ -9,7 +9,9 @@ on:
       - '**'
 
 env:
+  PRIMARY_ESLINT_VERSION: '^8.0.0'
   PRIMARY_NODE_VERSION: 18
+  PRIMARY_TYPESCRIPT_VERSION: '~4.8.0'
 
 defaults:
   run:
@@ -114,6 +116,7 @@ jobs:
     strategy:
       matrix:
         # just run on the oldest and latest supported versions and assume the intermediate versions are good
+        # unfortunately you can't reference environment variables in an array :(
         node-version: [14, 18]
         package:
           [
@@ -169,6 +172,88 @@ jobs:
           # Sadly 1 day is the minimum
           retention-days: 1
 
+  unit_tests_ts_regression:
+    name: Run Unit Tests (TypeScript Version Regression Checks)
+    needs: [build]
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        package:
+          # note that we don't regression test all packages here on purpose because most don't depend on TS directly.
+          ['eslint-plugin', 'scope-manager', 'type-utils', 'typescript-estree']
+
+        ts-version:
+          # unfortunately you can't reference environment variables in an array :(
+          ['3.3.1', '~4.0.0', '~4.8.0']
+    env:
+      # Added the - at the end to function as a separator to improve readability in the PR comment from the Nx cloud app
+      NX_CLOUD_ENV_NAME: 'Node ${{ matrix.node-version }} -'
+      COLLECT_COVERAGE: false
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 2
+      - name: Install
+        uses: ./.github/actions/prepare-install
+        with:
+          node-version: ${{ env.PRIMARY_NODE_VERSION }}
+      - name: Build
+        uses: ./.github/actions/prepare-build
+
+      - name: Install Specific TS Version
+        run: |
+          yarn ts-node ./tools/change-ts-version.ts ${{ matrix.ts-version }}
+          yarn --ignore-engines --ignore-scripts
+
+      - name: Patch Packages
+        if: matrix.ts-version == env.PRIMARY_TYPESCRIPT_VERSION
+        run: |
+          yarn patch-package
+
+      # we don't collect coverage for these tests on purpose
+      - name: Run unit tests for ${{ matrix.package }}
+        run: npx nx test @typescript-eslint/${{ matrix.package }} --coverage=false
+        env:
+          CI: true
+
+  unit_tests_eslint_regression:
+    name: Run Unit Tests (ESLint Version Regression Checks)
+    needs: [build]
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        package:
+          # note that we don't regression test all packages here on purpose because most don't depend on ESLint directly.
+          ['eslint-plugin', 'utils']
+        eslint-version:
+          # unfortunately you can't reference environment variables in an array :(
+          ['6.0.0', '7.0.0', '^8.0.0']
+    env:
+      # Added the - at the end to function as a separator to improve readability in the PR comment from the Nx cloud app
+      NX_CLOUD_ENV_NAME: 'Node ${{ matrix.node-version }} -'
+      COLLECT_COVERAGE: false
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 2
+      - name: Install
+        uses: ./.github/actions/prepare-install
+        with:
+          node-version: ${{ env.PRIMARY_NODE_VERSION }}
+      - name: Build
+        uses: ./.github/actions/prepare-build
+
+      - name: Install Specific ESLint Version
+        run: yarn add -DW --ignore-engines --ignore-scripts eslint@${{ matrix.eslint-version }}
+
+      # we don't collect coverage for these tests on purpose
+      - name: Run unit tests for ${{ matrix.package }}
+        run: npx nx test @typescript-eslint/${{ matrix.package }} --coverage=false
+        env:
+          CI: true
+
   website_tests:
     name: Website tests
     needs: [build]

tools/change-ts-version.ts

@@ -0,0 +1,17 @@
+import fs from 'fs';
+import path from 'path';
+import semver from 'semver';
+import packageJson = require('../package.json');
+
+const newVersion = semver.valid(semver.coerce(process.argv[2]));
+if (newVersion == null) {
+  throw new Error('The first argument passed must be a valid semver');
+}
+
+packageJson.resolutions.typescript = newVersion;
+packageJson.devDependencies.typescript = newVersion;
+
+fs.writeFileSync(
+  path.resolve(__dirname, '../package.json'),
+  JSON.stringify(packageJson, null, 2),
+);

tools/generate-contributors.ts

@@ -21,7 +21,7 @@ interface Contributor {
   contributions: number;
   type: string;
   login?: string;
-  url?: string;
+  url: string;
   avatar_url?: string;
   html_url?: string;
 }

tools/tsconfig.json

@@ -0,0 +1,10 @@
+{
+  "extends": "../tsconfig.base.json",
+  "compilerOptions": {
+    "esModuleInterop": true,
+    "resolveJsonModule": true,
+    "rootDir": ".."
+  },
+  "include": ["./*.ts"],
+  "references": []
+}