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

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

@@ -5315,4 +5315,16 @@ 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

@@ -732,7 +732,7 @@ ${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) {
       let hoisted = this.hoistedRequires.get(dep.id);
@@ -741,10 +741,28 @@ ${code}
         this.hoistedRequires.set(dep.id, hoisted);
       }
 
-      hoisted.set(
-        resolvedAsset.id,
-        `var $${publicId} = parcelRequire(${JSON.stringify(publicId)});`,
+      let resolvedAssetUsedSymbols = nullthrows(
+        this.bundleGraph.getUsedSymbols(resolvedAsset),
       );
+
+      // Check to see if the exportSymbol is in the resolved asset or the dependency's
+      // set of used symbols. If the exportSymbol is 'default', check that the
+      // default export from the resolved asset is used.
+      // If the exportSymbol is '*', a non-empty set of the resolved asset's used symbols
+      // indicates the export(s) is used.
+      let isExportSymbolUsed =
+        resolvedAssetUsedSymbols.has(exportSymbol) ||
+        nullthrows(this.bundleGraph.getUsedSymbols(dep)).has(exportSymbol) ||
+        (exportSymbol === 'default' &&
+          resolvedAssetUsedSymbols.has(exportSymbol)) ||
+        (exportSymbol === '*' && resolvedAssetUsedSymbols.size > 0);
+
+      if (isExportSymbolUsed) {
+        hoisted.set(
+          resolvedAsset.id,
+          `var $${publicId} = parcelRequire(${JSON.stringify(publicId)});`,
+        );
+      }
     }
 
     if (isWrapped) {