Ensure named exports are prioritized over wildcard re-exports (#7016)

Author: devongovett

packages/core/integration-tests/test/integration/scope-hoisting/es6/re-export-priority/a.mjs

@@ -0,0 +1,2 @@
+export const foo = 2;
+export * from './foo.mjs'

packages/core/integration-tests/test/integration/scope-hoisting/es6/re-export-priority/b.mjs

@@ -0,0 +1,2 @@
+export * from './foo.mjs'
+export const foo = 2;

packages/core/integration-tests/test/integration/scope-hoisting/es6/re-export-priority/entry-a.mjs

@@ -0,0 +1,2 @@
+import {foo} from './a.mjs';
+output = foo;

packages/core/integration-tests/test/integration/scope-hoisting/es6/re-export-priority/entry-b.mjs

@@ -0,0 +1,2 @@
+import {foo} from './b.mjs';
+output = foo;

packages/core/integration-tests/test/integration/scope-hoisting/es6/re-export-priority/foo.mjs

@@ -0,0 +1 @@
+export const foo = 3;

packages/core/integration-tests/test/integration/scope-hoisting/es6/re-export-priority/namespace-a.mjs

@@ -0,0 +1,2 @@
+import * as a from './a.mjs';
+output = a;

packages/core/integration-tests/test/integration/scope-hoisting/es6/re-export-priority/namespace-b.mjs

@@ -0,0 +1,2 @@
+import * as b from './b.mjs';
+output = b;

packages/core/integration-tests/test/javascript.js

@@ -4843,6 +4843,30 @@ describe('javascript', function() {
     assert.equal(typeof res.c, 'function');
   });
 
+  it('should prioritize named exports before re-exports withput scope hoisting (before)', async () => {
+    let b = await bundle(
+      path.join(
+        __dirname,
+        'integration/scope-hoisting/es6/re-export-priority/entry-a.mjs',
+      ),
+    );
+
+    let res = await run(b, null, {require: false});
+    assert.equal(res.output, 2);
+  });
+
+  it('should prioritize named exports before re-exports without scope hoisting (after)', async () => {
+    let b = await bundle(
+      path.join(
+        __dirname,
+        'integration/scope-hoisting/es6/re-export-priority/entry-b.mjs',
+      ),
+    );
+
+    let res = await run(b, null, {require: false});
+    assert.equal(res.output, 2);
+  });
+
   it('should exclude default from export all declaration', async function() {
     let b = await bundle(
       path.join(__dirname, 'integration/js-export-all/index.js'),

packages/core/integration-tests/test/scope-hoisting.js

@@ -3774,6 +3774,54 @@ describe('scope hoisting', function() {
         test: 'foo',
       });
     });
+
+    it('should prioritize named exports before re-exports (before)', async () => {
+      let b = await bundle(
+        path.join(
+          __dirname,
+          'integration/scope-hoisting/es6/re-export-priority/entry-a.mjs',
+        ),
+      );
+
+      let res = await run(b);
+      assert.equal(res, 2);
+    });
+
+    it('should prioritize named exports before re-exports (after)', async () => {
+      let b = await bundle(
+        path.join(
+          __dirname,
+          'integration/scope-hoisting/es6/re-export-priority/entry-b.mjs',
+        ),
+      );
+
+      let res = await run(b);
+      assert.equal(res, 2);
+    });
+
+    it('should prioritize named exports before re-exports in namespace (before)', async () => {
+      let b = await bundle(
+        path.join(
+          __dirname,
+          'integration/scope-hoisting/es6/re-export-priority/namespace-a.mjs',
+        ),
+      );
+
+      let res = await run(b);
+      assert.deepEqual(res, {foo: 2});
+    });
+
+    it('should prioritize named exports before re-exports in namespace (after)', async () => {
+      let b = await bundle(
+        path.join(
+          __dirname,
+          'integration/scope-hoisting/es6/re-export-priority/namespace-b.mjs',
+        ),
+      );
+
+      let res = await run(b);
+      assert.deepEqual(res, {foo: 2});
+    });
   });
 
   describe('commonjs', function() {

packages/packagers/js/src/helpers.js

@@ -38,7 +38,7 @@ export const helpers = {
 `,
   $parcel$exportWildcard: `function $parcel$exportWildcard(dest, source) {
   Object.keys(source).forEach(function(key) {
-    if (key === 'default' || key === '__esModule') {
+    if (key === 'default' || key === '__esModule' || dest.hasOwnProperty(key)) {
       return;
     }
 

packages/transformers/js/src/esmodule-helpers.js

@@ -8,12 +8,7 @@ exports.defineInteropFlag = function(a) {
 
 exports.exportAll = function(source, dest) {
   Object.keys(source).forEach(function(key) {
-    if (key === 'default' || key === '__esModule') {
-      return;
-    }
-
-    // Skip duplicate re-exports when they have the same value.
-    if (key in dest && dest[key] === source[key]) {
+    if (key === 'default' || key === '__esModule' || dest.hasOwnProperty(key)) {
       return;
     }