fix: read ambigous TS files with type-stripping enabled with require first

.eslintignore

@@ -6,4 +6,5 @@ bundle.compat.js
 bundle.native.js
 wt
 test/e2e/report
+test/module-loading/test-projects
 tmp

.github/workflows/module-loading.yml

@@ -0,0 +1,29 @@
+name: Module Loading Tests
+
+on:
+    push:
+        branches: [master]
+    pull_request:
+        branches: [master]
+
+jobs:
+    module-loading:
+        runs-on: ubuntu-latest
+
+        steps:
+            - uses: actions/checkout@v4
+
+            - name: Use Node.js 24.x
+              uses: actions/setup-node@v4
+              with:
+                  node-version: 24.x
+                  cache: "npm"
+
+            - name: Install dependencies
+              run: npm ci
+
+            - name: Build project
+              run: npm run build
+
+            - name: Run module loading tests
+              run: npm run test-module-loading

package.json

@@ -30,7 +30,8 @@
     "lint": "eslint --cache . && prettier --check .",
     "reformat": "eslint --fix . && prettier --write .",
     "prettier-watch": "onchange '**' --exclude-path .prettierignore -- prettier --write {{changed}}",
-    "test-unit": "_mocha \"test/!(integration)/**/*.js\"",
+    "test-unit": "_mocha \"test/!(integration|module-loading)/**/*.js\"",
+    "test-module-loading": "mocha test/module-loading/index.js",
     "test": "npm run test-unit && npm run check-types && npm run lint",
     "test-integration": "mocha -r ts-node/register -r test/integration/*/**",
     "toc": "doctoc docs --title '### Contents'",

src/test-reader/mocha-reader/index.js

@@ -1,7 +1,9 @@
 "use strict";
 
+const fs = require("fs");
 const _ = require("lodash");
 const Mocha = require("mocha");
+const path = require("path");
 
 const { MochaEventBus } = require("./mocha-event-bus");
 const { TreeBuilderDecorator } = require("./tree-builder-decorator");
@@ -11,6 +13,8 @@ const { getMethodsByInterface } = require("./utils");
 const logger = require("../../utils/logger");
 const { enableSourceMaps } = require("../../utils/typescript");
 
+const AMBIGUOUS_TYPESCRIPT_EXTENSIONS = new Set([".ts", ".tsx"]);
+
 function getTagParser(original) {
     return function (title, paramsOrFn, fn) {
         if (typeof paramsOrFn === "function") {
@@ -59,7 +63,7 @@ async function readFiles(files, { esmDecorator, config, eventBus, runnableOpts,
     files.forEach(f => mocha.addFile(f));
 
     try {
-        await mocha.loadFilesAsync({ esmDecorator });
+        await loadMochaFiles(mocha, files, { esmDecorator });
     } catch (err) {
         const errorMessage = (err.message || "").split("\n")[0].trim();
 
@@ -77,6 +81,66 @@ async function readFiles(files, { esmDecorator, config, eventBus, runnableOpts,
     applyOnly(mocha.suite, eventBus);
 }
 
+async function loadMochaFiles(mocha, files, { esmDecorator }) {
+    if (["true", "1"].includes(process.env.TESTPLANE_LOAD_FILES_ASYNC) || !files.some(shouldLoadWithRequire)) {
+        await mocha.loadFilesAsync({ esmDecorator });
+        return;
+    }
+
+    const originalFiles = mocha.files;
+    mocha.lazyLoadFiles(true);
+
+    try {
+        for (const file of files) {
+            mocha.files = [file];
+
+            if (!shouldLoadWithRequire(file)) {
+                await mocha.loadFilesAsync({ esmDecorator });
+                continue;
+            }
+
+            try {
+                mocha.loadFiles();
+            } catch (err) {
+                if (err.code !== "ERR_REQUIRE_ESM" && err.code !== "ERR_REQUIRE_ASYNC_MODULE") {
+                    throw err;
+                }
+
+                await mocha.loadFilesAsync({ esmDecorator });
+            }
+        }
+    } finally {
+        mocha.files = originalFiles;
+    }
+}
+
+function shouldLoadWithRequire(file) {
+    if (!process.features?.typescript || !AMBIGUOUS_TYPESCRIPT_EXTENSIONS.has(path.extname(file))) {
+        return false;
+    }
+
+    // Node.js 24 can import .ts files directly and warn before our require hook transpiles them.
+    return !isInsideEsmPackage(file);
+}
+
+function isInsideEsmPackage(file) {
+    let currentDir = path.dirname(path.resolve(file));
+    let parentDir;
+
+    while (currentDir !== parentDir) {
+        const packageJsonPath = path.join(currentDir, "package.json");
+
+        if (fs.existsSync(packageJsonPath)) {
+            return JSON.parse(fs.readFileSync(packageJsonPath, "utf8")).type === "module";
+        }
+
+        parentDir = currentDir;
+        currentDir = path.dirname(currentDir);
+    }
+
+    return false;
+}
+
 function initBuildContext(outBus) {
     outBus.emit(TestReaderEvents.NEW_BUILD_INSTRUCTION, ctx => {
         ctx.treeBuilder = TreeBuilderDecorator.create(ctx.treeBuilder);

test/module-loading/index.js

@@ -0,0 +1,44 @@
+"use strict";
+
+const path = require("path");
+const execa = require("execa");
+
+const TESTPLANE_BIN = path.resolve(__dirname, "../../bin/testplane");
+const PROJECTS_DIR = path.resolve(__dirname, "test-projects");
+const MODULE_TYPE_WARNING = "MODULE_TYPELESS_PACKAGE_JSON";
+
+const projects = [
+    ["js-cjs", "js-cjs test"],
+    ["js-esm", "js-esm test"],
+    ["ts-cjs", "ts-cjs test"],
+    ["ts-esm", "ts-esm test"],
+];
+
+describe("module loading", () => {
+    projects.forEach(([projectName, testTitle]) => {
+        it(`reads ${projectName}`, async () => {
+            const { stdout, stderr } = await readTests(projectName);
+            const tests = JSON.parse(stdout);
+
+            assert.lengthOf(tests, 1);
+            assert.deepEqual(tests[0].titlePath, [projectName, testTitle]);
+            assert.deepEqual(tests[0].browserIds, ["chrome"]);
+            assert.isFalse(tests[0].pending);
+            assert.notInclude(stderr, MODULE_TYPE_WARNING);
+        });
+    });
+});
+
+function readTests(projectName) {
+    return execa(
+        process.execPath,
+        [TESTPLANE_BIN, "list-tests", "-c", "testplane.config.cjs", "tests", "--formatter", "list"],
+        {
+            cwd: path.join(PROJECTS_DIR, projectName),
+            env: {
+                ...process.env,
+                NODE_OPTIONS: [process.env.NODE_OPTIONS, "--trace-warnings"].filter(Boolean).join(" "),
+            },
+        },
+    );
+}

test/module-loading/test-projects/js-cjs/package.json

@@ -0,0 +1,4 @@
+{
+  "name": "module-loading-js-cjs",
+  "private": true
+}

test/module-loading/test-projects/js-cjs/testplane.config.cjs

@@ -0,0 +1,11 @@
+"use strict";
+
+module.exports = {
+    browsers: {
+        chrome: {
+            desiredCapabilities: {
+                browserName: "chrome",
+            },
+        },
+    },
+};

test/module-loading/test-projects/js-cjs/tests/basic.test.js

@@ -0,0 +1,8 @@
+"use strict";
+
+const assert = require("node:assert");
+const { value } = require("./helpers/value");
+
+describe("js-cjs", () => {
+    it("js-cjs test", () => assert.equal(value, "js-cjs-value"));
+});

test/module-loading/test-projects/js-cjs/tests/helpers/value.js

@@ -0,0 +1,5 @@
+"use strict";
+
+module.exports = {
+    value: "js-cjs-value",
+};

test/module-loading/test-projects/js-esm/package.json

@@ -0,0 +1,5 @@
+{
+  "name": "module-loading-js-esm",
+  "private": true,
+  "type": "module"
+}

test/module-loading/test-projects/js-esm/testplane.config.cjs

@@ -0,0 +1,11 @@
+"use strict";
+
+module.exports = {
+    browsers: {
+        chrome: {
+            desiredCapabilities: {
+                browserName: "chrome",
+            },
+        },
+    },
+};

test/module-loading/test-projects/js-esm/tests/basic.test.js

@@ -0,0 +1,6 @@
+import assert from "node:assert";
+import { value } from "./helpers/value.js";
+
+describe("js-esm", () => {
+    it("js-esm test", () => assert.equal(value, "js-esm-value"));
+});

test/module-loading/test-projects/js-esm/tests/helpers/value.js

@@ -0,0 +1 @@
+export const value = "js-esm-value";

test/module-loading/test-projects/ts-cjs/package.json

@@ -0,0 +1,5 @@
+{
+  "name": "module-loading-ts-cjs",
+  "private": true,
+  "type": "commonjs"
+}

test/module-loading/test-projects/ts-cjs/testplane.config.cjs

@@ -0,0 +1,11 @@
+"use strict";
+
+module.exports = {
+    browsers: {
+        chrome: {
+            desiredCapabilities: {
+                browserName: "chrome",
+            },
+        },
+    },
+};

test/module-loading/test-projects/ts-cjs/tests/basic.test.ts

@@ -0,0 +1,7 @@
+import assert from "node:assert";
+
+const { value } = require("./helpers/value");
+
+describe("ts-cjs", () => {
+    it("ts-cjs test", () => assert.equal(value, "ts-cjs-value"));
+});

test/module-loading/test-projects/ts-cjs/tests/helpers/value.js

@@ -0,0 +1,5 @@
+"use strict";
+
+module.exports = {
+    value: "ts-cjs-value",
+};

test/module-loading/test-projects/ts-esm/package.json

@@ -0,0 +1,5 @@
+{
+  "name": "module-loading-ts-esm",
+  "private": true,
+  "type": "module"
+}

test/module-loading/test-projects/ts-esm/testplane.config.cjs

@@ -0,0 +1,11 @@
+"use strict";
+
+module.exports = {
+    browsers: {
+        chrome: {
+            desiredCapabilities: {
+                browserName: "chrome",
+            },
+        },
+    },
+};

test/module-loading/test-projects/ts-esm/tests/basic.test.ts

@@ -0,0 +1,6 @@
+import assert from "node:assert";
+import { value } from "./helpers/value.ts";
+
+describe("ts-esm", () => {
+    it("ts-esm test", () => assert.equal(value, "ts-esm-value"));
+});

test/module-loading/test-projects/ts-esm/tests/helpers/value.ts

@@ -0,0 +1 @@
+export const value = "ts-esm-value";