From eddd3206dc6cb6f3666b1824760c4f61ebc497bf Mon Sep 17 00:00:00 2001
From: Tobias Koppers <tobias.koppers@googlemail.com>
Date: Tue, 15 Sep 2020 12:21:37 +0200
Subject: [PATCH] add raw export for named reexport from non-harmony

---
 lib/ConcatenationScope.js                      | 18 ++++++++++++++++++
 ...HarmonyExportImportedSpecifierDependency.js | 14 ++++++++++++--
 lib/optimize/ConcatenatedModule.js             | 15 +++++++++++++--
 types.d.ts                                     |  6 ++++++
 4 files changed, 49 insertions(+), 4 deletions(-)

diff --git a/lib/ConcatenationScope.js b/lib/ConcatenationScope.js
index 30a55e94c..3eec5ef5f 100644
--- a/lib/ConcatenationScope.js
+++ b/lib/ConcatenationScope.js
@@ -23,6 +23,7 @@ const NAMESPACE_OBJECT_EXPORT = "__WEBPACK_NAMESPACE_OBJECT__";
  * @property {number} index
  * @property {Module} module
  * @property {Map<string, string>} exportMap mapping from export name to symbol
+ * @property {Map<string, string>} rawExportMap mapping from export name to symbol
  * @property {string=} namespaceExportSymbol
  */
 
@@ -64,11 +65,28 @@ class ConcatenationScope {
 	 * @param {string} symbol identifier of the export in source code
 	 */
 	registerExport(exportName, symbol) {
+		if (!this._currentModule.exportMap) {
+			this._currentModule.exportMap = new Map();
+		}
 		if (!this._currentModule.exportMap.has(exportName)) {
 			this._currentModule.exportMap.set(exportName, symbol);
 		}
 	}
 
+	/**
+	 *
+	 * @param {string} exportName name of the export
+	 * @param {string} expression expression to be used
+	 */
+	registerRawExport(exportName, expression) {
+		if (!this._currentModule.rawExportMap) {
+			this._currentModule.rawExportMap = new Map();
+		}
+		if (!this._currentModule.rawExportMap.has(exportName)) {
+			this._currentModule.rawExportMap.set(exportName, expression);
+		}
+	}
+
 	/**
 	 * @param {string} symbol identifier of the export in source code
 	 */
diff --git a/lib/dependencies/HarmonyExportImportedSpecifierDependency.js b/lib/dependencies/HarmonyExportImportedSpecifierDependency.js
index bdabe9111..a7272405b 100644
--- a/lib/dependencies/HarmonyExportImportedSpecifierDependency.js
+++ b/lib/dependencies/HarmonyExportImportedSpecifierDependency.js
@@ -746,13 +746,23 @@ HarmonyExportImportedSpecifierDependency.Template = class HarmonyExportImportedS
 	 * @returns {void}
 	 */
 	apply(dependency, source, templateContext) {
-		if (templateContext.concatenationScope) return;
-		const { moduleGraph, runtime } = templateContext;
+		const { moduleGraph, runtime, concatenationScope } = templateContext;
 
 		const dep = /** @type {HarmonyExportImportedSpecifierDependency} */ (dependency);
 
 		const mode = dep.getMode(moduleGraph, runtime);
 
+		if (concatenationScope) {
+			switch (mode.type) {
+				case "reexport-undefined":
+					concatenationScope.registerRawExport(
+						mode.name,
+						"/* reexport non-default export from non-harmony */ undefined"
+					);
+			}
+			return;
+		}
+
 		if (mode.type !== "unused" && mode.type !== "empty-star") {
 			super.apply(dependency, source, templateContext);
 
diff --git a/lib/optimize/ConcatenatedModule.js b/lib/optimize/ConcatenatedModule.js
index 40d375427..a7bed6db3 100644
--- a/lib/optimize/ConcatenatedModule.js
+++ b/lib/optimize/ConcatenatedModule.js
@@ -90,6 +90,7 @@ const propertyAccess = require("../util/propertyAccess");
  * @property {Scope} moduleScope
  * @property {Map<string, string>} internalNames
  * @property {Map<string, string>} exportMap
+ * @property {Map<string, string>} rawExportMap
  * @property {string=} namespaceExportSymbol
  * @property {string} namespaceObjectName
  * @property {boolean} interopNamespaceObjectUsed
@@ -326,7 +327,7 @@ const getFinalBinding = (
 	switch (info.type) {
 		case "concatenated": {
 			const exportId = exportName[0];
-			const directExport = info.exportMap.get(exportId);
+			const directExport = info.exportMap && info.exportMap.get(exportId);
 			if (directExport) {
 				const usedName = /** @type {string[]} */ (exportsInfo.getUsedName(
 					exportName,
@@ -339,6 +340,15 @@ const getFinalBinding = (
 					exportName
 				};
 			}
+			const rawExport = info.rawExportMap && info.rawExportMap.get(exportId);
+			if (rawExport) {
+				return {
+					info,
+					rawName: rawExport,
+					ids: exportName.slice(1),
+					exportName
+				};
+			}
 			const reexport = exportInfo.findTarget(moduleGraph, module =>
 				moduleToInfoMap.has(module)
 			);
@@ -1495,7 +1505,8 @@ class ConcatenatedModule extends Module {
 						globalScope: undefined,
 						moduleScope: undefined,
 						internalNames: new Map(),
-						exportMap: new Map(),
+						exportMap: undefined,
+						rawExportMap: undefined,
 						namespaceExportSymbol: undefined,
 						namespaceObjectName: undefined,
 						interopNamespaceObjectUsed: false,
diff --git a/types.d.ts b/types.d.ts
index 2b506f8e8..4685c897b 100644
--- a/types.d.ts
+++ b/types.d.ts
@@ -1674,6 +1674,11 @@ declare interface ConcatenatedModuleInfo {
 	 * mapping from export name to symbol
 	 */
 	exportMap: Map<string, string>;
+
+	/**
+	 * mapping from export name to symbol
+	 */
+	rawExportMap: Map<string, string>;
 	namespaceExportSymbol?: string;
 }
 declare interface ConcatenationBailoutReasonContext {
@@ -1694,6 +1699,7 @@ declare class ConcatenationScope {
 	);
 	isModuleInScope(module: Module): boolean;
 	registerExport(exportName: string, symbol: string): void;
+	registerRawExport(exportName: string, expression: string): void;
 	registerNamespaceExport(symbol: string): void;
 	createModuleReference(
 		module: Module,