From 0cad0de3e3fb29506a3f0d8844546fb0645b527a Mon Sep 17 00:00:00 2001
From: Joel Einbinder <joel.einbinder@gmail.com>
Date: Mon, 8 Nov 2021 16:25:40 -0500
Subject: [PATCH] fix(test runner): better error message when importing
 typescript from esmodule (#10061)

---
 packages/playwright-test/src/loader.ts |  8 ++++++++
 tests/playwright-test/loader.spec.ts   | 24 ++++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/packages/playwright-test/src/loader.ts b/packages/playwright-test/src/loader.ts
index 32ef13d363..e281981bfb 100644
--- a/packages/playwright-test/src/loader.ts
+++ b/packages/playwright-test/src/loader.ts
@@ -208,6 +208,14 @@ export class Loader {
         }
       }
     } catch (error) {
+      if (error.code === 'ERR_MODULE_NOT_FOUND' && error.message.includes('Did you mean to import')) {
+        const didYouMean = /Did you mean to import (.*)\?/.exec(error.message)?.[1];
+        if (didYouMean?.endsWith('.ts'))
+          throw errorWithFile(file, 'Cannot import a typescript file from an esmodule.');
+      }
+      if (error.code === 'ERR_UNKNOWN_FILE_EXTENSION' && error.message.includes('.ts'))
+        throw errorWithFile(file, 'Cannot import a typescript file from an esmodule.');
+
       if (error instanceof SyntaxError && error.message.includes('Cannot use import statement outside a module'))
         throw errorWithFile(file, 'JavaScript files must end with .mjs to use import.');
 
diff --git a/tests/playwright-test/loader.spec.ts b/tests/playwright-test/loader.spec.ts
index 72170f2d0e..4ad1ca69e8 100644
--- a/tests/playwright-test/loader.spec.ts
+++ b/tests/playwright-test/loader.spec.ts
@@ -215,3 +215,27 @@ test('should load esm config files', async ({ runInlineTest }) => {
   expect(result.exitCode).toBe(0);
   expect(result.passed).toBe(1);
 });
+
+test('should fail to load ts from esm when package.json has type module', async ({ runInlineTest }) => {
+  const result = await runInlineTest({
+    'playwright.config.js': `
+      //@no-header
+      import * as fs from 'fs';
+      export default { projects: [{name: 'foo'}] };
+    `,
+    'package.json': JSON.stringify({ type: 'module' }),
+    'a.test.js': `
+      import { foo } from './b.ts';
+      const { test } = pwt;
+      test('check project name', ({}, testInfo) => {
+        expect(testInfo.project.name).toBe('foo');
+      });
+    `,
+    'b.ts': `
+      export const foo: string = 'foo';
+    `
+  });
+
+  expect(result.exitCode).toBe(1);
+  expect(result.output).toContain('Cannot import a typescript file from an esmodule');
+});