fix(track): don't throw on revoked proxies @W-17739481

packages/@lwc/engine-core/src/framework/mutation-logger.ts

@@ -60,6 +60,18 @@ function safelyCallGetter(target: any, key: PropertyKey) {
     }
 }
 
+function isRevokedProxy(target: object) {
+    try {
+        // `str in obj` will never throw for normal objects or active proxies,
+        // but the operation is not allowed for revoked proxies
+        // eslint-disable-next-line @typescript-eslint/no-unused-expressions
+        '' in target;
+        return false;
+    } catch (_) {
+        return true;
+    }
+}
+
 /**
  * Flush all the logs we've written so far and return the current logs.
  */
@@ -126,7 +138,9 @@ export function trackTargetForMutationLogging(key: PropertyKey, target: any) {
         // Guard against recursive objects - don't traverse forever
         return;
     }
-    if (isObject(target) && !isNull(target)) {
+
+    // Revoked proxies (e.g. window props in LWS sandboxes) throw an error if we try to track them
+    if (isObject(target) && !isNull(target) && !isRevokedProxy(target)) {
         // only track non-primitives; others are invalid as WeakMap keys
         targetsToPropertyKeys.set(target, key);
 

packages/@lwc/engine-server/src/__tests__/fixtures/track-revoked-proxy-fails/expected.html

@@ -0,0 +1,5 @@
+<x-component>
+  <template shadowrootmode="open">
+    I should render!
+  </template>
+</x-component>

packages/@lwc/engine-server/src/__tests__/fixtures/track-revoked-proxy-fails/index.js

@@ -0,0 +1,3 @@
+export const tagName = 'x-component';
+export { default } from 'x/component';
+export * from 'x/component';

packages/@lwc/engine-server/src/__tests__/fixtures/track-revoked-proxy-fails/modules/x/component/component.html

@@ -0,0 +1,3 @@
+<template>
+    I should render!
+</template>

packages/@lwc/engine-server/src/__tests__/fixtures/track-revoked-proxy-fails/modules/x/component/component.js

@@ -0,0 +1,26 @@
+import { LightningElement, track } from 'lwc';
+import tmpl from './component.html';
+
+const { revoke, proxy } = Proxy.revocable({}, {});
+revoke();
+
+export default class Rehydration extends LightningElement {
+    // Doesn't need to be used, just needs to be tracked; see W-17739481
+    @track reactive = proxy;
+
+    connectedCallback() {
+        Promise.resolve().then(() => {
+            this.reactive = 1;
+        });
+    }
+
+    render() {
+        if (!this.rendered) {
+            this.rendered = true;
+        } else {
+            throw new Error('Reactivity should be disabled on SSR.');
+        }
+
+        return tmpl;
+    }
+}