fix(commonjs): idempotence issue (#871)

Author: thorn0

packages/commonjs/src/index.js

@@ -72,6 +72,7 @@ export default function commonjs(options = {}) {
 
   const esModulesWithDefaultExport = new Set();
   const esModulesWithNamedExports = new Set();
+  const isCjsPromises = new Map();
 
   const ignoreRequire =
     typeof options.ignore === 'function'
@@ -208,7 +209,8 @@ export default function commonjs(options = {}) {
           actualId,
           getRequireReturnsDefault(actualId),
           esModulesWithDefaultExport,
-          esModulesWithNamedExports
+          esModulesWithNamedExports,
+          isCjsPromises
         );
       }
 
@@ -244,11 +246,11 @@ export default function commonjs(options = {}) {
       if (commonjs) {
         const isCjs = commonjs.isCommonJS;
         if (isCjs != null) {
-          setIsCjsPromise(id, isCjs);
+          setIsCjsPromise(isCjsPromises, id, isCjs);
           return;
         }
       }
-      setIsCjsPromise(id, null);
+      setIsCjsPromise(isCjsPromises, id, null);
     }
   };
 }

packages/commonjs/src/is-cjs.js

@@ -1,6 +1,4 @@
-const isCjsPromises = new Map();
-
-export function getIsCjsPromise(id) {
+export function getIsCjsPromise(isCjsPromises, id) {
   let isCjsPromise = isCjsPromises.get(id);
   if (isCjsPromise) return isCjsPromise.promise;
 
@@ -16,7 +14,7 @@ export function getIsCjsPromise(id) {
   return promise;
 }
 
-export function setIsCjsPromise(id, resolution) {
+export function setIsCjsPromise(isCjsPromises, id, resolution) {
   const isCjsPromise = isCjsPromises.get(id);
   if (isCjsPromise) {
     if (isCjsPromise.resolve) {

packages/commonjs/src/proxies.js

@@ -46,10 +46,11 @@ export async function getStaticRequireProxy(
   id,
   requireReturnsDefault,
   esModulesWithDefaultExport,
-  esModulesWithNamedExports
+  esModulesWithNamedExports,
+  isCjsPromises
 ) {
   const name = getName(id);
-  const isCjs = await getIsCjsPromise(id);
+  const isCjs = await getIsCjsPromise(isCjsPromises, id);
   if (isCjs) {
     return `import { __moduleExports } from ${JSON.stringify(id)}; export default __moduleExports;`;
   } else if (isCjs === null) {

packages/commonjs/test/test.js

@@ -759,3 +759,18 @@ if (Number(/^v(\d+)/.exec(process.version)[1]) >= 12) {
     t.is(code, await new Promise((done) => getRollupUpCodeWithCache.on('message', done)));
   });
 }
+
+test('does not affect subsequently created instances when called with `requireReturnsDefault: "preferred"`', async (t) => {
+  const input = 'fixtures/function/import-esm-require-returns-default-preferred/main.js';
+  const options = { requireReturnsDefault: 'preferred' };
+
+  const instance1 = commonjs(options);
+  const bundle1 = await rollup({ input, plugins: [instance1] });
+  const code1 = (await bundle1.generate({})).output[0].code;
+
+  const instance2 = commonjs(options);
+  const bundle2 = await rollup({ input, plugins: [instance2] });
+  const code2 = (await bundle2.generate({})).output[0].code;
+
+  t.is(code1, code2);
+});