packages/acceptance-tests/pkg-tests-specs/sources/pnp-esm.test.ts

@@ -1028,4 +1028,32 @@ describe(`Plug'n'Play - ESM`, () => {
       ),
     );
   });
+
+  it(
+    `should use the commonjs resolver in commonjs files imported from ESM`,
+    makeTemporaryEnv(
+      {
+        type: `module`,
+      },
+      async ({path, run, source}) => {
+        await xfs.writeFilePromise(ppath.join(path, `foo.js` as Filename), `import './bar.cjs';`);
+        await xfs.writeFilePromise(
+          ppath.join(path, `bar.cjs` as Filename),
+          `
+          require('module')._extensions['.custom'] = require('module')._extensions['.js'];
+          require('./baz');
+          `,
+        );
+        await xfs.writeFilePromise(ppath.join(path, `baz.custom` as Filename), `console.log(42);`);
+
+        await expect(run(`install`)).resolves.toMatchObject({code: 0});
+
+        await expect(run(`node`, `./foo.js`)).resolves.toMatchObject({
+          code: 0,
+          stdout: `42\n`,
+          stderr: ``,
+        });
+      },
+    ),
+  );
 });

packages/plugin-pnp/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@yarnpkg/plugin-pnp",
-  "version": "3.2.12",
+  "version": "3.2.13",
   "license": "BSD-2-Clause",
   "main": "./sources/index.ts",
   "dependencies": {

packages/yarnpkg-cli/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@yarnpkg/cli",
-  "version": "3.6.2",
+  "version": "3.6.3",
   "license": "BSD-2-Clause",
   "main": "./sources/index.ts",
   "dependencies": {

packages/yarnpkg-pnp/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@yarnpkg/pnp",
-  "version": "3.3.4",
+  "version": "3.3.5",
   "license": "BSD-2-Clause",
   "main": "./sources/index.ts",
   "dependencies": {

packages/yarnpkg-pnp/sources/esm-loader/hooks/load.ts

@@ -15,7 +15,7 @@ export async function load(
     };
   },
   nextLoad: typeof load,
-): Promise<{ format: string, source: string, shortCircuit: boolean }> {
+): Promise<{ format: string, source?: string, shortCircuit: boolean }> {
   const url = loaderUtils.tryParseURL(urlString);
   if (url?.protocol !== `file:`)
     return nextLoad(urlString, context, nextLoad);
@@ -49,7 +49,7 @@ export async function load(
 
   return {
     format,
-    source: await fs.promises.readFile(filePath, `utf8`),
+    source: format === `commonjs` ? undefined : await fs.promises.readFile(filePath, `utf8`),
     shortCircuit: true,
   };
 }