[WIP] feat: test old TypeScript version

.github/actions/prepare-install/action.yml

@@ -7,6 +7,9 @@ inputs:
   registry-url:
     description: "Define registry-url"
     required: false
+  typescript-version:
+    description: "A modified TypeScript version to setup"
+    required: false
 
 # outputs: - no outputs
 
@@ -17,6 +20,13 @@ runs:
       shell: bash
       run: echo ${{ github.ref }}
 
+    - if: ${{ inputs.typescript-version != null }}
+      run: |
+        cat package.json | awk '{sub(/typescript\":\ \"[0-9.]+/,"typescript\": \"${{ inputs.typescript-version }}")}1' > package.tmp.json
+        cp package.tmp.json package.json
+      shell: bash
+      name: Set TypeScript resolution to ${{ inputs.typescript-version }}
+
     - name: Use Node.js ${{ inputs.node-version }}
       uses: actions/setup-node@v3
       with:
@@ -34,13 +44,21 @@ runs:
         path: |
           ${{ steps.yarn-cache-dir-path.outputs.dir }}
           ~/.cache/Cypress
-        key: ${{ runner.os }}-yarn-${{ hashFiles('**/yarn.lock') }}
+        key: ${{ runner.os }}-yarn-${{ hashFiles('**/yarn.lock') }}-${{ hashFiles('package.json') }}
         restore-keys: |
           ${{ runner.os }}-yarn-
 
-    # if the cache was hit - this will run in <1s
-    - name: Install dependencies
+    # if the cache was hit - these will run in <1s
+
+    - if: ${{ inputs.typescript-version == null }}
+      name: Install dependencies (frozen)
       shell: bash
       run: |
         yarn --ignore-engines --frozen-lockfile --ignore-scripts
         yarn check-clean-workspace-after-install
+
+    - if: ${{ inputs.typescript-version != null }}
+      name: Install dependencies
+      shell: bash
+      run: |
+        yarn --ignore-engines --ignore-scripts

.github/workflows/ci.yml

@@ -122,6 +122,7 @@ jobs:
       matrix:
         # just run on the oldest and latest supported versions and assume the intermediate versions are good
         node-version: [12, 18]
+        typescript-version: [4.0.0, null]
         package: [
           "ast-spec",
           "eslint-plugin",
@@ -136,7 +137,7 @@ jobs:
         ]
     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 }} -'
+      NX_CLOUD_ENV_NAME: 'Node ${{ matrix.node-version }} TS ${{ matrix.typescript-version }}-'
       COLLECT_COVERAGE: false
     steps:
       - name: Checkout
@@ -147,6 +148,7 @@ jobs:
         uses: ./.github/actions/prepare-install
         with:
           node-version: ${{ env.PRIMARY_NODE_VERSION }}
+          typescript-version: ${{ matrix.typescript-version }}
       - name: Build
         uses: ./.github/actions/prepare-build
 

packages/utils/package.json

@@ -44,12 +44,14 @@
     "@typescript-eslint/types": "5.30.7",
     "@typescript-eslint/typescript-estree": "5.30.7",
     "eslint-scope": "^5.1.1",
-    "eslint-utils": "^3.0.0"
+    "eslint-utils": "^3.0.0",
+    "semver": "^7.3.7"
   },
   "peerDependencies": {
     "eslint": "^6.0.0 || ^7.0.0 || ^8.0.0"
   },
   "devDependencies": {
+    "@types/semver": "^7.3.10",
     "typescript": "*"
   },
   "funding": {

packages/utils/src/eslint-utils/RuleTester.ts

@@ -1,5 +1,8 @@
 import * as path from 'path';
+import * as semver from 'semver';
+import * as ts from 'typescript';
 import * as TSESLint from '../ts-eslint';
+import { ValidTestCase } from '../ts-eslint';
 
 const parser = '@typescript-eslint/parser';
 
@@ -73,31 +76,32 @@ class RuleTester extends TSESLint.RuleTester {
 
     const tests = { ...testsReadonly };
 
-    // standardize the valid tests as objects
-    tests.valid = tests.valid.map(test => {
-      if (typeof test === 'string') {
-        return {
-          code: test,
-        };
-      }
-      return test;
-    });
-
-    tests.valid = tests.valid.map(test => {
-      if (typeof test !== 'string') {
-        if (test.parser === parser) {
-          throw new Error(errorMessage);
-        }
-        if (!test.filename) {
+    tests.valid = tests.valid
+      // standardize the valid tests as objects
+      .map(test => {
+        if (typeof test === 'string') {
           return {
-            ...test,
-            filename: this.getFilename(test.parserOptions),
+            code: test,
           };
         }
-      }
-      return test;
-    });
-    tests.invalid = tests.invalid.map(test => {
+        return test;
+      })
+      .filter(isValidTsVersion)
+      .map(test => {
+        if (typeof test !== 'string') {
+          if (test.parser === parser) {
+            throw new Error(errorMessage);
+          }
+          if (!test.filename) {
+            return {
+              ...test,
+              filename: this.getFilename(test.parserOptions),
+            };
+          }
+        }
+        return test;
+      });
+    tests.invalid = tests.invalid.filter(isValidTsVersion).map(test => {
       if (test.parser === parser) {
         throw new Error(errorMessage);
       }
@@ -114,6 +118,15 @@ class RuleTester extends TSESLint.RuleTester {
   }
 }
 
+function isValidTsVersion(testCase: ValidTestCase): boolean {
+  return (
+    !testCase.tsVersion ||
+    semver.satisfies(ts.version, `>= ${testCase.tsVersion}`, {
+      includePrerelease: true,
+    })
+  );
+}
+
 /**
  * Simple no-op tag to mark code samples as "should not format with prettier"
  *   for the internal/plugin-test-formatting lint rule

packages/utils/src/ts-eslint/RuleTester.ts

@@ -8,7 +8,9 @@ import {
   SharedConfigurationSettings,
 } from './Rule';
 
-interface ValidTestCase<TOptions extends Readonly<unknown[]>> {
+interface ValidTestCase<
+  TOptions extends Readonly<unknown[]> = Readonly<unknown[]>,
+> {
   /**
    * Name for the test case.
    * @since 8.1.0
@@ -46,6 +48,10 @@ interface ValidTestCase<TOptions extends Readonly<unknown[]>> {
    * Settings for the test case.
    */
   readonly settings?: Readonly<SharedConfigurationSettings>;
+  /**
+   * Semver of TypeScript version(s) to run against (by default, all versions).
+   */
+  readonly tsVersion?: string;
   /**
    * Run this case exclusively for debugging in supported test frameworks.
    * @since 7.29.0
@@ -73,8 +79,8 @@ interface SuggestionOutput<TMessageIds extends string> {
 }
 
 interface InvalidTestCase<
-  TMessageIds extends string,
-  TOptions extends Readonly<unknown[]>,
+  TMessageIds extends string = string,
+  TOptions extends Readonly<unknown[]> = Readonly<unknown[]>,
 > extends ValidTestCase<TOptions> {
   /**
    * Expected errors.