fix infinite loop on circular inner graph references

lib/optimize/InnerGraphPlugin.js

@@ -117,6 +117,7 @@ class InnerGraphPlugin {
 											if (itemValue !== undefined) {
 												for (const i of itemValue) {
 													if (i === key) continue;
+													if (value.has(i)) continue;
 													newSet.add(i);
 													if (typeof i !== "string") {
 														isTerminal = false;

test/cases/inner-graph/circular2/index.js

@@ -0,0 +1,14 @@
+import { x, y, z, a, f3 } from "./module";
+
+it("should be able to handle circular referenced", () => {
+	expect(x()).toEqual([y, z]);
+	const [_a, b, c, d] = a();
+	expect(b()).toEqual([a, b, c, d]);
+	expect(c()).toEqual([a, b, c, d]);
+	expect(d()).toEqual([a, b, c, d]);
+	const [f2, f4] = f3();
+	const [f1, _f3] = f2();
+	expect(_f3).toBe(f3);
+	expect(f3()).toEqual(f1());
+	expect(f2()).toEqual(f4());
+});

test/cases/inner-graph/circular2/module.js

@@ -0,0 +1,49 @@
+function x() {
+	return [y, z];
+}
+
+function y() {
+	return [x, z];
+}
+
+function z() {
+	return [x, y];
+}
+
+export { x, y, z };
+
+function a() {
+	return [a, b, c, d];
+}
+
+function b() {
+	return [a, b, c, d];
+}
+
+function c() {
+	return [a, b, c, d];
+}
+
+function d() {
+	return [a, b, c, d];
+}
+
+export { a };
+
+function f1() {
+	return [f2, f4];
+}
+
+function f2() {
+	return [f1, f3];
+}
+
+function f3() {
+	return [f2, f4];
+}
+
+function f4() {
+	return [f1, f3];
+}
+
+export { f3 };

test/fixtures/temp-watch-1569996664301/bundle.js

@@ -0,0 +1,24 @@
+/******/ (() => { // webpackBootstrap
+/******/ 	var __webpack_modules__ = ({
+
+/***/ "./test/fixtures/temp-watch-1569996664301/file.js":
+/*!****************************************************************!*\
+  !*** (webpack)/test/fixtures/temp-watch-1569996664301/file.js ***!
+  \****************************************************************/
+/*! exports [maybe provided (runtime-defined)] [no usage info] */
+/*! runtime requirements:  */
+/***/ (() => {
+
+eval("'bar'\n\n//# sourceURL=webpack:///(webpack)/test/fixtures/temp-watch-1569996664301/file.js?");
+
+/***/ })
+
+/******/ 	});
+/************************************************************************/
+/******/
+/************************************************************************/
+/******/ 	// startup
+/******/ 	// Load entry module
+/******/ 	__webpack_modules__["./test/fixtures/temp-watch-1569996664301/file.js"]();
+/******/ })()
+;