From dfb6a403357d5ac2c0ea87aa6e5a4f947de342f8 Mon Sep 17 00:00:00 2001
From: Kai Riemann <53490304+kri@users.noreply.github.com>
Date: Sat, 17 Oct 2020 18:47:52 +0200
Subject: [PATCH] [Fast Refresh] Fix crashes caused by rogue Proxies (#20030)
 (#20039)

---
 .../react-refresh/src/ReactFreshRuntime.js    | 14 +++++++++++--
 .../src/__tests__/ReactFresh-test.js          | 21 +++++++++++++++++++
 2 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/packages/react-refresh/src/ReactFreshRuntime.js b/packages/react-refresh/src/ReactFreshRuntime.js
index e6f0fb70ae5c6..cd5d5a6716bf8 100644
--- a/packages/react-refresh/src/ReactFreshRuntime.js
+++ b/packages/react-refresh/src/ReactFreshRuntime.js
@@ -178,6 +178,16 @@ function cloneSet<T>(set: Set<T>): Set<T> {
   return clone;
 }
 
+// This is a safety mechanism to protect against rogue getters and Proxies.
+function getProperty(object, property) {
+  try {
+    return object[property];
+  } catch (err) {
+    // Intentionally ignore.
+    return undefined;
+  }
+}
+
 export function performReactRefresh(): RefreshUpdate | null {
   if (!__DEV__) {
     throw new Error(
@@ -322,7 +332,7 @@ export function register(type: any, id: string): void {
 
     // Visit inner types because we might not have registered them.
     if (typeof type === 'object' && type !== null) {
-      switch (type.$$typeof) {
+      switch (getProperty(type, '$$typeof')) {
         case REACT_FORWARD_REF_TYPE:
           register(type.render, id + '$render');
           break;
@@ -676,7 +686,7 @@ export function isLikelyComponentType(type: any): boolean {
       }
       case 'object': {
         if (type != null) {
-          switch (type.$$typeof) {
+          switch (getProperty(type, '$$typeof')) {
             case REACT_FORWARD_REF_TYPE:
             case REACT_MEMO_TYPE:
               // Definitely React components.
diff --git a/packages/react-refresh/src/__tests__/ReactFresh-test.js b/packages/react-refresh/src/__tests__/ReactFresh-test.js
index 3b6f69b13e318..da73032520c64 100644
--- a/packages/react-refresh/src/__tests__/ReactFresh-test.js
+++ b/packages/react-refresh/src/__tests__/ReactFresh-test.js
@@ -3612,11 +3612,26 @@ describe('ReactFresh', () => {
       const useStore = () => {};
       expect(ReactFreshRuntime.isLikelyComponentType(useStore)).toBe(false);
       expect(ReactFreshRuntime.isLikelyComponentType(useTheme)).toBe(false);
+      const rogueProxy = new Proxy(
+        {},
+        {
+          get(target, property) {
+            throw new Error();
+          },
+        },
+      );
+      expect(ReactFreshRuntime.isLikelyComponentType(rogueProxy)).toBe(false);
 
       // These seem like function components.
       const Button = () => {};
       expect(ReactFreshRuntime.isLikelyComponentType(Button)).toBe(true);
       expect(ReactFreshRuntime.isLikelyComponentType(Widget)).toBe(true);
+      const ProxyButton = new Proxy(Button, {
+        get(target, property) {
+          return target[property];
+        },
+      });
+      expect(ReactFreshRuntime.isLikelyComponentType(ProxyButton)).toBe(true);
       const anon = (() => () => {})();
       anon.displayName = 'Foo';
       expect(ReactFreshRuntime.isLikelyComponentType(anon)).toBe(true);
@@ -3624,8 +3639,14 @@ describe('ReactFresh', () => {
       // These seem like class components.
       class Btn extends React.Component {}
       class PureBtn extends React.PureComponent {}
+      const ProxyBtn = new Proxy(Btn, {
+        get(target, property) {
+          return target[property];
+        },
+      });
       expect(ReactFreshRuntime.isLikelyComponentType(Btn)).toBe(true);
       expect(ReactFreshRuntime.isLikelyComponentType(PureBtn)).toBe(true);
+      expect(ReactFreshRuntime.isLikelyComponentType(ProxyBtn)).toBe(true);
       expect(
         ReactFreshRuntime.isLikelyComponentType(
           createReactClass({render() {}}),