fix(extension): do not provide fork to closed tabs (#838)

Relates to #820

Handler to update the redirect rules might not have been called because
the listener chain crapped out on this bug.

deployables/extension/src/background/companionEnablement.spec.ts

@@ -19,7 +19,7 @@ import {
   type CompanionResponseMessage,
   type Message,
 } from '@zodiac/messages'
-import { mockActiveTab, mockTab } from '@zodiac/test-utils/chrome'
+import { mockActiveTab, mockTab, mockTabClose } from '@zodiac/test-utils/chrome'
 import { beforeEach, describe, expect, it, vi } from 'vitest'
 import { companionEnablement } from './companionEnablement'
 import { trackRequests } from './rpcTracking'
@@ -68,6 +68,22 @@ describe('Companion Enablement', () => {
         forkUrl: 'http://test-rpc.com',
       })
     })
+
+    it('does not notify the companion app when the tab has been closed', async () => {
+      await startPilotSession({ windowId: 1, tabId: 2 })
+
+      const tab = await connectCompanionApp({ id: 2, windowId: 1 })
+
+      await mockTabClose(tab.id)
+
+      await startSimulation({
+        windowId: 1,
+        chainId: Chain.ETH,
+        rpcUrl: 'http://test-rpc.com',
+      })
+
+      expect(chromeMock.tabs.sendMessage).toHaveBeenCalledTimes(1)
+    })
   })
 
   describe('Connection status', () => {

deployables/extension/src/background/companionEnablement.ts

@@ -39,7 +39,7 @@ export const companionEnablement = (
 
           console.debug('Companion App connected!')
 
-          onSimulationUpdate.addListener(async (fork) => {
+          const dispose = onSimulationUpdate.addListener(async (fork) => {
             invariant(tab.id != null, 'Tab needs an ID')
 
             console.debug('Sending updated fork to companion app', { fork })
@@ -52,6 +52,18 @@ export const companionEnablement = (
             captureLastError()
           })
 
+          const handleTabClose = (tabId: number) => {
+            if (tabId !== tab.id) {
+              return
+            }
+
+            chrome.tabs.onRemoved.removeListener(handleTabClose)
+
+            dispose()
+          }
+
+          chrome.tabs.onRemoved.addListener(handleTabClose)
+
           break
         }
 

deployables/extension/src/background/createEventListener.ts

@@ -17,6 +17,10 @@ export const createEventListener = <
       return {
         addListener(listener) {
           listeners.add(listener)
+
+          return () => {
+            listeners.delete(listener)
+          }
         },
         removeAllListeners() {
           listeners.clear()

deployables/extension/src/background/types.ts

@@ -7,8 +7,10 @@ export interface Fork {
 
 export type EventFn = (...args: any) => void
 
+type DisposeFn = () => void
+
 export type Event<T extends EventFn = () => void> = {
-  addListener: (listener: T) => void
+  addListener: (listener: T) => DisposeFn
   removeListener: (listener: T) => void
   removeAllListeners: () => void
 }

deployables/extension/test-utils/connectCompanionApp.ts

@@ -8,12 +8,16 @@ import { callListeners, chromeMock, createMockTab } from './chrome'
 export const connectCompanionApp = async (
   tab: Partial<chrome.tabs.Tab> = {},
 ) => {
+  const connectedTab = createMockTab(tab)
+
   await callListeners(
     chromeMock.runtime.onMessage,
     {
       type: CompanionAppMessageType.REQUEST_FORK_INFO,
     } satisfies CompanionAppMessage,
-    { id: chrome.runtime.id, tab: createMockTab(tab) },
+    { id: chrome.runtime.id, tab: connectedTab },
     vi.fn(),
   )
+
+  return connectedTab
 }

packages/test-utils/src/chrome/index.ts

@@ -4,6 +4,7 @@ export * from './creators'
 export { mockActiveTab } from './mockActiveTab'
 export { mockRuntimeConnect } from './mockRuntimeConnect'
 export { mockTab } from './mockTab'
+export { mockTabClose } from './mockTabClose'
 export { mockTabConnect } from './mockTabConnect'
 export { mockTabSwitch } from './mockTabSwitch'
 export { createStorageMock } from './storageMock'

packages/test-utils/src/chrome/mockTabClose.ts

@@ -0,0 +1,8 @@
+import { callListeners } from './callListeners'
+import { chromeMock } from './chromeMock'
+
+export const mockTabClose = (tabId: number) =>
+  callListeners(chromeMock.tabs.onRemoved, tabId, {
+    isWindowClosing: false,
+    windowId: 1,
+  })