Scope Hoisting: Don't insert unused requires that aren't registered a…

…nywhere (#7764)

packages/core/integration-tests/test/integration/scope-hoisting/es6/unused-require/index.js

@@ -0,0 +1,3 @@
+import {foo} from './library';
+
+output = foo;

packages/core/integration-tests/test/integration/scope-hoisting/es6/unused-require/library/foo/index.js

@@ -0,0 +1,2 @@
+export const unusedFoo = 'unusedFoo';
+export { foo } from './other';

packages/core/integration-tests/test/integration/scope-hoisting/es6/unused-require/library/foo/other.js

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

packages/core/integration-tests/test/integration/scope-hoisting/es6/unused-require/library/foo/package.json

@@ -0,0 +1,3 @@
+{
+  "sideEffects": false
+}

packages/core/integration-tests/test/integration/scope-hoisting/es6/unused-require/library/index.js

@@ -0,0 +1,3 @@
+export { foo, unusedFoo } from './foo';
+
+eval('')

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

@@ -5336,4 +5336,16 @@ describe('scope hoisting', function () {
     let output = await run(b);
     assert.strictEqual(output, 'bar foo bar');
   });
+
+  it("not insert unused requires that aren't registered anywhere", async function () {
+    let b = await bundle(
+      path.join(
+        __dirname,
+        '/integration/scope-hoisting/es6/unused-require/index.js',
+      ),
+    );
+
+    let output = await run(b);
+    assert.strictEqual(output, 'foo');
+  });
 });

packages/packagers/js/src/ScopeHoistingPackager.js

@@ -760,9 +760,18 @@ ${code}
     let staticExports = resolvedAsset.meta.staticExports !== false;
     let publicId = this.bundleGraph.getAssetPublicId(resolvedAsset);
 
-    // If the rsolved asset is wrapped, but imported at the top-level by this asset,
+    // If the resolved asset is wrapped, but imported at the top-level by this asset,
     // then we hoist parcelRequire calls to the top of this asset so side effects run immediately.
-    if (isWrapped && dep && !dep?.meta.shouldWrap && symbol !== false) {
+    if (
+      isWrapped &&
+      dep &&
+      !dep?.meta.shouldWrap &&
+      symbol !== false &&
+      // Only do this if the asset is part of a different bundle (so it was definitely
+      // parcelRequire.register'ed there), or if it is indeed registered in this bundle.
+      (!this.bundle.hasAsset(resolvedAsset) ||
+        !this.shouldSkipAsset(resolvedAsset))
+    ) {
       let hoisted = this.hoistedRequires.get(dep.id);
       if (!hoisted) {
         hoisted = new Map();