Make sure circular export * from X does not stack overflow

src/Module.ts

@@ -308,7 +308,13 @@ export default class Module {
 		);
 	}
 
-	getReexports() {
+	getReexports(walkedModuleIds = new Set<string>()) {
+		// avoid infinite recursion when using circular `export * from X`
+		if (walkedModuleIds.has(this.id)) {
+			return [];
+		}
+		walkedModuleIds.add(this.id);
+
 		const reexports = Object.create(null);
 
 		for (const name in this.reexports) {
@@ -321,7 +327,9 @@ export default class Module {
 				return;
 			}
 
-			for (const name of (<Module>module).getExports().concat((<Module>module).getReexports())) {
+			for (const name of (<Module>module)
+				.getExports()
+				.concat((<Module>module).getReexports(walkedModuleIds))) {
 				if (name !== 'default') reexports[name] = true;
 			}
 		});

test/function/samples/cycles-export-star/_config.js

@@ -0,0 +1,18 @@
+const assert = require('assert');
+
+module.exports = {
+	description: 'does not stack overflow on `export * from X` cycles',
+	code(code) {
+		assert.equal(
+			code,
+			`'use strict';\n\nfunction b() {\n\treturn 'b';\n}\n\nassert.equal(b(), 'b');\n`
+		);
+	},
+	warnings: [
+		{
+			code: 'CIRCULAR_DEPENDENCY',
+			importer: 'a.js',
+			message: 'Circular dependency: a.js -> b.js -> a.js'
+		}
+	]
+};

test/function/samples/cycles-export-star/a.js

@@ -0,0 +1,5 @@
+export * from './b.js';
+
+export function a() {
+	return 'a';
+}

test/function/samples/cycles-export-star/b.js

@@ -0,0 +1,5 @@
+export * from './a.js';
+
+export function b() {
+	return 'b';
+}

test/function/samples/cycles-export-star/main.js

@@ -0,0 +1,3 @@
+import { b } from './a.js';
+
+assert.equal(b(), 'b');