fix: non-reference clone of transferred listeners (#1080)

* fix: structured clone of transferred listeners

* test: map reference breaking

src/lifecycleEvents.ts

@@ -15,7 +15,9 @@ import { Logger } from './logger/logger';
 
 // Data of any type can be passed to the callback. Can be cast to any type that is given in emit().
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
-type callback = (data: any) => Promise<void>;
+export type callback = (data: any) => Promise<void>;
+type ListenerMap = Map<string, callback>;
+export type UniqueListenerMap = Map<string, ListenerMap>;
 
 declare const global: {
   salesforceCoreLifecycle?: Lifecycle;
@@ -49,7 +51,7 @@ export class Lifecycle {
 
   private constructor(
     private readonly listeners: Dictionary<callback[]> = {},
-    private readonly uniqueListeners: Map<string, Map<string, callback>> = new Map<string, Map<string, callback>>()
+    private readonly uniqueListeners: UniqueListenerMap = new Map<string, Map<string, callback>>()
   ) {}
 
   /**
@@ -89,8 +91,11 @@ export class Lifecycle {
     ) {
       const oldInstance = global.salesforceCoreLifecycle;
       // use the newer version and transfer any listeners from the old version
-      // object spread keeps them from being references
-      global.salesforceCoreLifecycle = new Lifecycle({ ...oldInstance.listeners }, oldInstance.uniqueListeners);
+      // object spread and the clone fn keep them from being references
+      global.salesforceCoreLifecycle = new Lifecycle(
+        { ...oldInstance.listeners },
+        cloneUniqueListeners(oldInstance.uniqueListeners)
+      );
       // clean up any listeners on the old version
       Object.keys(oldInstance.listeners).map((eventName) => {
         oldInstance.removeAllListeners(eventName);
@@ -176,7 +181,7 @@ export class Lifecycle {
     if (uniqueListenerIdentifier) {
       if (!this.uniqueListeners.has(eventName)) {
         // nobody is listening to the event yet
-        this.uniqueListeners.set(eventName, new Map<string, callback>([[uniqueListenerIdentifier, cb]]));
+        this.uniqueListeners.set(eventName, new Map([[uniqueListenerIdentifier, cb]]));
       } else if (!this.uniqueListeners.get(eventName)?.has(uniqueListenerIdentifier)) {
         // the unique listener identifier is not already registered
         this.uniqueListeners.get(eventName)?.set(uniqueListenerIdentifier, cb);
@@ -231,3 +236,7 @@ export class Lifecycle {
     }
   }
 }
+
+const cloneListeners: (listeners: ListenerMap) => ListenerMap = (listeners) => new Map(Array.from(listeners.entries()));
+export const cloneUniqueListeners = (uniqueListeners: UniqueListenerMap): UniqueListenerMap =>
+  new Map(Array.from(uniqueListeners.entries()).map(([key, value]) => [key, cloneListeners(value)]));

test/unit/lifecycleEventsTest.ts

@@ -9,7 +9,7 @@
 import { Duration, sleep } from '@salesforce/kit/lib/duration';
 import { spyMethod } from '@salesforce/ts-sinon';
 import * as chai from 'chai';
-import { Lifecycle } from '../../src/lifecycleEvents';
+import { Lifecycle, callback, cloneUniqueListeners } from '../../src/lifecycleEvents';
 import { TestContext } from '../../src/testSetup';
 import { Logger } from '../../src/logger/logger';
 
@@ -257,3 +257,29 @@ describe('lifecycleEvents', () => {
     lifecycle2.removeAllListeners('test7');
   });
 });
+
+describe('listener map cloning', () => {
+  const cb = (): Promise<void> => Promise.resolve();
+  it('clones map, breaking event name reference', () => {
+    const map1 = new Map<string, Map<string, callback>>();
+    map1.set('evt', new Map([['uniqueId', cb]]));
+
+    const map2 = cloneUniqueListeners(map1);
+    chai.expect(map2).to.deep.equal(map1);
+    map1.delete('evt');
+    chai.expect(map1.has('evt')).to.be.false;
+    chai.expect(map2.has('evt')).to.be.true;
+  });
+  it('clones map, breaking uniqueId reference', () => {
+    const map1 = new Map<string, Map<string, callback>>();
+    map1.set('evt', new Map([['uniqueId', cb]]));
+
+    const map2 = cloneUniqueListeners(map1);
+    chai.expect(map2).to.deep.equal(map1);
+    map2.get('evt')?.set('uniqueId2', cb);
+    chai.expect(map1.has('evt')).to.be.true;
+    chai.expect(map2.has('evt')).to.be.true;
+    chai.expect(map1.get('evt')?.has('uniqueId2')).to.be.false;
+    chai.expect(map2.get('evt')?.has('uniqueId2')).to.be.true;
+  });
+});