From bd150648a853e4177ca528f56bc39df1e3e7ee99 Mon Sep 17 00:00:00 2001
From: Lukas Taegert-Atkinson <lukas.taegert-atkinson@tngtech.com>
Date: Sat, 23 Apr 2022 14:27:49 +0200
Subject: [PATCH] Throw proper error when indirectly reexporting a recursive
 binding

---
 src/Module.ts                                 | 40 +++++++++++++++----
 .../samples/circular-reexport/_config.js      | 12 ++++++
 .../samples/circular-reexport/main.js         |  3 ++
 3 files changed, 48 insertions(+), 7 deletions(-)
 create mode 100644 test/function/samples/circular-reexport/_config.js
 create mode 100644 test/function/samples/circular-reexport/main.js

diff --git a/src/Module.ts b/src/Module.ts
index e65975a4325..1e7c4ada2ba 100644
--- a/src/Module.ts
+++ b/src/Module.ts
@@ -134,7 +134,7 @@ function getVariableForExportNameRecursive(
 	target: Module | ExternalModule,
 	name: string,
 	importerForSideEffects: Module | undefined,
-	isExportAllSearch: boolean,
+	isExportAllSearch: boolean | undefined,
 	searchedNamesAndModules = new Map<string, Set<Module | ExternalModule>>()
 ): [variable: Variable | null, indirectExternal?: boolean] {
 	const searchedModules = searchedNamesAndModules.get(name);
@@ -561,7 +561,10 @@ export default class Module {
 				return [this.exportShimVariable];
 			}
 			const name = exportDeclaration.localName;
-			const variable = this.traceVariable(name, importerForSideEffects)!;
+			const variable = this.traceVariable(name, {
+				importerForSideEffects,
+				searchedNamesAndModules
+			})!;
 			if (importerForSideEffects) {
 				getOrCreate(
 					importerForSideEffects.sideEffectDependenciesByVariable,
@@ -793,7 +796,18 @@ export default class Module {
 		};
 	}
 
-	traceVariable(name: string, importerForSideEffects?: Module): Variable | null {
+	traceVariable(
+		name: string,
+		{
+			importerForSideEffects,
+			isExportAllSearch,
+			searchedNamesAndModules
+		}: {
+			importerForSideEffects?: Module;
+			isExportAllSearch?: boolean;
+			searchedNamesAndModules?: Map<string, Set<Module | ExternalModule>>;
+		} = EMPTY_OBJECT
+	): Variable | null {
 		const localVariable = this.scope.variables.get(name);
 		if (localVariable) {
 			return localVariable;
@@ -807,9 +821,13 @@ export default class Module {
 				return otherModule.namespace;
 			}
 
-			const [declaration] = otherModule.getVariableForExportName(importDeclaration.name, {
-				importerForSideEffects: importerForSideEffects || this
-			});
+			const [declaration] = getVariableForExportNameRecursive(
+				otherModule,
+				importDeclaration.name,
+				importerForSideEffects || this,
+				isExportAllSearch,
+				searchedNamesAndModules
+			);
 
 			if (!declaration) {
 				return this.error(
@@ -1057,7 +1075,9 @@ export default class Module {
 				name,
 				importerForSideEffects,
 				true,
-				searchedNamesAndModules
+				// We are creating a copy to handle the case where the same binding is
+				// imported through different namespace reexports gracefully
+				copyNameToModulesMap(searchedNamesAndModules)
 			);
 
 			if (module instanceof ExternalModule || indirectExternal) {
@@ -1199,3 +1219,9 @@ function setAlternativeExporterIfCyclic(
 		}
 	}
 }
+
+const copyNameToModulesMap = (
+	searchedNamesAndModules?: Map<string, Set<Module | ExternalModule>>
+): Map<string, Set<Module | ExternalModule>> | undefined =>
+	searchedNamesAndModules &&
+	new Map(Array.from(searchedNamesAndModules, ([name, modules]) => [name, new Set(modules)]));
diff --git a/test/function/samples/circular-reexport/_config.js b/test/function/samples/circular-reexport/_config.js
new file mode 100644
index 00000000000..6379705fca7
--- /dev/null
+++ b/test/function/samples/circular-reexport/_config.js
@@ -0,0 +1,12 @@
+const path = require('path');
+const ID_MAIN = path.join(__dirname, 'main.js');
+
+module.exports = {
+	description: 'throws proper error for circular reexports',
+	error: {
+		code: 'CIRCULAR_REEXPORT',
+		id: ID_MAIN,
+		message: '"foo" cannot be exported from main.js as it is a reexport that references itself.',
+		watchFiles: [ID_MAIN]
+	}
+};
diff --git a/test/function/samples/circular-reexport/main.js b/test/function/samples/circular-reexport/main.js
new file mode 100644
index 00000000000..6572efc076a
--- /dev/null
+++ b/test/function/samples/circular-reexport/main.js
@@ -0,0 +1,3 @@
+import { foo } from './main.js';
+
+export { foo };