fix exporting globals in scope-hoisted modules

fixes webpack#7905

Author: sokra

lib/optimize/ConcatenatedModule.js

@@ -136,6 +136,9 @@ const getFinalName = (
 				} else if (!info.module.isUsed(exportName)) {
 					return "/* unused export */ undefined";
 				}
+				if (info.globalExports.has(directExport)) {
+					return directExport;
+				}
 				const name = info.internalNames.get(directExport);
 				if (!name) {
 					throw new Error(
@@ -562,6 +565,7 @@ class ConcatenatedModule extends Module {
 						globalScope: undefined,
 						moduleScope: undefined,
 						internalNames: new Map(),
+						globalExports: new Set(),
 						exportMap: exportMap,
 						reexportMap: reexportMap,
 						hasNamespaceObject: false,
@@ -941,6 +945,19 @@ class ConcatenatedModule extends Module {
 					}
 				}
 			}
+
+			// add exported globals
+			if (info.type === "concatenated") {
+				const variables = new Set();
+				for (const variable of info.moduleScope.variables) {
+					variables.add(variable.name);
+				}
+				for (const [, variable] of info.exportMap) {
+					if (!variables.has(variable)) {
+						info.globalExports.add(variable);
+					}
+				}
+			}
 		}
 
 		// generate names for symbols

test/configCases/scope-hoisting/export-global/index.js

@@ -0,0 +1,7 @@
+import { process as p } from "./module";
+import { process as p2 } from "./module2";
+
+it("should export globals correctly", () => {
+	expect(p).toBe(42);
+	expect(p2).toBe(process);
+});

test/configCases/scope-hoisting/export-global/module.js

@@ -0,0 +1,2 @@
+const process = 42;
+export { process };

test/configCases/scope-hoisting/export-global/module2.js

@@ -0,0 +1 @@
+export { process };

test/configCases/scope-hoisting/export-global/webpack.config.js

@@ -0,0 +1,5 @@
+module.exports = {
+	optimization: {
+		concatenateModules: true
+	}
+};