fix(re-exports): reexports runtime calculation should not accessing __WEBPACK_IMPORT_KEY__ decl with var (#20249)

JSerFeng · web-flow · commit 2efd21b0b06b · 2025-12-18T15:16:57.000+03:00
diff --git a/.changeset/clean-mugs-rescue.md b/.changeset/clean-mugs-rescue.md
@@ -0,0 +1,5 @@
+---
+"webpack": patch
+---
+
+Reexports runtime calculation should not accessing **WEBPACK_IMPORT_KEY** decl with var.
diff --git a/lib/dependencies/HarmonyExportImportedSpecifierDependency.js b/lib/dependencies/HarmonyExportImportedSpecifierDependency.js
@@ -1251,9 +1251,11 @@ HarmonyExportImportedSpecifierDependency.Template = class HarmonyExportImportedS
 				}
 
 				content += "__WEBPACK_REEXPORT_OBJECT__[__WEBPACK_IMPORT_KEY__] = ";
-				content += runtimeTemplate.supportsArrowFunction()
-					? `() => ${importVar}[__WEBPACK_IMPORT_KEY__]`
-					: `function(key) { return ${importVar}[key]; }.bind(0, __WEBPACK_IMPORT_KEY__)`;
+				content +=
+					runtimeTemplate.supportsArrowFunction() &&
+					runtimeTemplate.supportsConst()
+						? `() => ${importVar}[__WEBPACK_IMPORT_KEY__]`
+						: `function(key) { return ${importVar}[key]; }.bind(0, __WEBPACK_IMPORT_KEY__)`;
 
 				runtimeRequirements.add(RuntimeGlobals.exports);
 				runtimeRequirements.add(RuntimeGlobals.definePropertyGetters);
diff --git a/test/configCases/externals/dynamic-reexports/index.js b/test/configCases/externals/dynamic-reexports/index.js
@@ -0,0 +1,9 @@
+import * as ns from './lib'
+
+it('should have correect reexport', () => {
+  expect(ns).toHaveProperty('readFile');
+  expect(ns).toHaveProperty('resolve');
+
+
+  expect(typeof ns.sep).toBe('string');
+})
diff --git a/test/configCases/externals/dynamic-reexports/lib.js b/test/configCases/externals/dynamic-reexports/lib.js
@@ -0,0 +1,5 @@
+// 2 external modules, the external module exportsType is unkown
+// so the exports of current module can only be known at runtime
+export * from 'path'
+
+export * from 'fs'
diff --git a/test/configCases/externals/dynamic-reexports/webpack.config.js b/test/configCases/externals/dynamic-reexports/webpack.config.js
@@ -0,0 +1,11 @@
+"use strict";
+
+module.exports = {
+	target: ["node"],
+	output: {
+		environment: {
+			arrowFunction: true,
+			const: false
+		}
+	}
+};

-Original file line number
+Diff line change
@@ @@ -0,0 +1,5 @@ @@
 +---
 +"webpack": patch
 +---
++
 +Reexports runtime calculation should not accessing **WEBPACK_IMPORT_KEY** decl with var.