fix(cjs): patch module.path for accurate cache ID

fixes #651

Author: privatenumber

.github/workflows/test.yml

@@ -10,7 +10,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, windows-latest]
-    timeout-minutes: 5
+    timeout-minutes: 10
 
     steps:
       - name: Checkout

src/@types/module.d.ts

@@ -20,6 +20,7 @@ declare module 'module' {
 	export const _cache: NodeJS.Require['cache'];
 
 	export type Parent = {
+		id: string;
 
 		/**
 		 * Can be null if the parent id is 'internal/preload' (e.g. via --require)

src/cjs/api/module-extensions.ts

@@ -1,4 +1,5 @@
 import fs from 'node:fs';
+import path from 'node:path';
 import Module from 'node:module';
 import type { TransformOptions } from 'esbuild';
 import { transformSync } from '../../utils/transform/index.js';
@@ -96,6 +97,17 @@ export const createExtensions = (
 			return defaultLoader(module, filePath);
 		}
 
+		/**
+		 * In new Module(), m.path = path.dirname(module.id) but module.id coming from
+		 * ESM resolver may be a data: path
+		 *
+		 * In these cases, we fix m.path to be the actual directory of the file
+		 */
+		// https://github.com/nodejs/node/blob/v22.8.0/lib/internal/modules/cjs/loader.js#L298
+		if (module.id.startsWith('data:text/javascript,')) {
+			module.path = path.dirname(cleanFilePath);
+		}
+
 		// For tracking dependencies in watch mode
 		if (parent?.send) {
 			parent.send({

tests/specs/smoke.ts

@@ -13,7 +13,7 @@ const wasmPath = path.resolve('tests/fixtures/test.wasm');
 const wasmPathUrl = pathToFileURL(wasmPath).toString();
 
 export default testSuite(async ({ describe }, { tsx, supports, version }: NodeApis) => {
-	describe('Smoke', ({ describe }) => {
+	describe('Smoke', ({ describe, test }) => {
 		for (const packageType of packageTypes) {
 			const isCommonJs = packageType === 'commonjs';
 
@@ -481,5 +481,44 @@ export default testSuite(async ({ describe }, { tsx, supports, version }: NodeAp
 				}
 			});
 		}
+
+		// https://github.com/privatenumber/tsx/issues/651
+		test('resolves same relative path from CJS loaded by ESM', async ({ onTestFail }) => {
+			await using fixture = await createFixture({
+				'package.json': createPackageJson({ type: 'commonjs' }),
+				a: {
+					'index.ts': `
+					import { value } from './value.js';
+
+					if (value !== 1) {
+						throw new Error('Unexpected value');
+					}
+					`,
+					'value.js': 'export const value = 1;',
+				},
+				b: {
+					'index.ts': `
+					import { value } from './value.js';
+
+					if (value !== 2) {
+						throw new Error('Unexpected value');
+					}
+					`,
+					'value.js': 'export const value = 2;',
+				},
+				'index.mjs': `
+				import './a/index.js';
+				import './b/index.js';
+				`,
+			});
+
+			const p = await tsx(['index.mjs'], {
+				cwd: fixture.path,
+			});
+			onTestFail(() => {
+				console.log(p);
+			});
+			expect(p.failed).toBe(false);
+		});
 	});
 });