Fix hoist of modules with multiple aliases

src/packagers/JSConcatPackager.js

@@ -219,8 +219,10 @@ class JSConcatPackager extends Packager {
 
     let depAsts = new Map();
     for (let depAsset of asset.depAssets.values()) {
-      let depAst = this.addDeps(depAsset, included);
-      depAsts.set(depAsset, depAst);
+      if (!depAsts.has(depAsset)) {
+        let depAst = this.addDeps(depAsset, included);
+        depAsts.set(depAsset, depAst);
+      }
     }
 
     let statements;

test/integration/scope-hoisting/commonjs/wrap-aliases/a.js

@@ -0,0 +1,6 @@
+try {
+    output = require('foo')
+}
+catch(_) {
+    output = require('foo-bar')
+}

test/integration/scope-hoisting/commonjs/wrap-aliases/package.json

@@ -0,0 +1,6 @@
+{
+    "name": "a",
+    "browser": {
+        "foo": "foo-bar"
+    }
+}

test/scope-hoisting.js

@@ -1054,6 +1054,18 @@ describe('scope hoisting', function() {
       assert.deepEqual(output, 9);
     });
 
+    it('should support two aliases to the same module', async function() {
+      let b = await bundle(
+        path.join(
+          __dirname,
+          '/integration/scope-hoisting/commonjs/wrap-aliases/a.js'
+        )
+      );
+
+      let output = await run(b);
+      assert.deepEqual(output, 42);
+    });
+
     it('should support optional requires', async function() {
       let b = await bundle(
         path.join(