fix(desktop): keep optional action handlers optional through the latest-actions adapters

The adapters wrapped every field in an arrow function, including the
optional ones. That makes an absent handler unconditionally truthy, and
several children gate on a handler's PRESENCE rather than just calling
it:

  - onDismissError    -> assistant-message.tsx renders the dismiss button
                         only when defined
  - onRestoreToMessage -> thread/index.tsx gates the restore-confirm flow
  - onTranscribeAudio  -> use-voice-recorder / use-voice-conversation gate
                         recording on it
  - onLoadMoreMessaging / onLoadMoreProfileSessions -> sidebar paging

So the adapter would paint a dead dismiss button and let voice recording
proceed into a no-op transcription path even when the controller had
deliberately left those handlers off.

Wrap an optional field only when it is currently present, and re-read the
latest value inside the wrapper so the stale-closure fix still applies.
Presence is stable for a given actions object (the controller mutates
fields in place rather than toggling a handler between defined and
undefined), while the closure is what churns — which is exactly what the
indirection re-reads.

Adds two regression tests: absent optional handlers stay undefined, and a
present optional handler still late-binds to the latest closure. The
first was verified to fail against the unconditional-wrapper form.

apps/desktop/src/app/contrib/latest-actions.test.ts

@@ -78,4 +78,48 @@ describe('latestActions adapters', () => {
     expect(staleNavigate).not.toHaveBeenCalled()
     expect(latestNavigate).toHaveBeenCalledWith(item)
   })
+
+  // An absent optional handler must stay absent through the adapter. Children
+  // gate on PRESENCE, not just invocation: onDismissError renders the dismiss
+  // button only when defined, onRestoreToMessage gates the restore-confirm
+  // flow, and onTranscribeAudio gates voice recording. Wrapping an undefined
+  // field in an arrow function makes it unconditionally truthy, which would
+  // paint a dead dismiss button and let voice recording run with no
+  // transcription backend.
+  it('leaves absent optional handlers undefined instead of always-truthy wrappers', () => {
+    const chat = makeChatActions()
+    chat.onDismissError = undefined
+    chat.onRestoreToMessage = undefined
+    chat.onTranscribeAudio = undefined
+
+    const adaptedChat = latestChatActions(chat)
+
+    expect(adaptedChat.onDismissError).toBeUndefined()
+    expect(adaptedChat.onRestoreToMessage).toBeUndefined()
+    expect(adaptedChat.onTranscribeAudio).toBeUndefined()
+
+    const sidebar = makeSidebarActions()
+    sidebar.onLoadMoreMessaging = undefined
+    sidebar.onLoadMoreProfileSessions = undefined
+
+    const adaptedSidebar = latestSidebarActions(sidebar)
+
+    expect(adaptedSidebar.onLoadMoreMessaging).toBeUndefined()
+    expect(adaptedSidebar.onLoadMoreProfileSessions).toBeUndefined()
+  })
+
+  it('still late-binds a PRESENT optional handler to the latest closure', async () => {
+    const staleTranscribe = vi.fn(async () => 'stale')
+    const latestTranscribe = vi.fn(async () => 'latest')
+    const actions = makeChatActions()
+    actions.onTranscribeAudio = staleTranscribe
+
+    const adapted = latestChatActions(actions)
+
+    actions.onTranscribeAudio = latestTranscribe
+
+    expect(adapted.onTranscribeAudio).toBeTypeOf('function')
+    await expect(adapted.onTranscribeAudio!(new Blob())).resolves.toBe('latest')
+    expect(staleTranscribe).not.toHaveBeenCalled()
+  })
 })

apps/desktop/src/app/contrib/latest-actions.ts

@@ -6,7 +6,28 @@ import type { ChatActions, SidebarActions } from './types'
  * directly, the child keeps the function from the surface's last render and can
  * submit/click against a stale session closure. These adapters keep a stable
  * wrapper but dereference the latest field at call time.
+ *
+ * OPTIONAL handlers must stay optional. Several children gate on a handler's
+ * *presence*, not just call it — `onDismissError` renders the dismiss button
+ * only when it exists (assistant-message.tsx), `onRestoreToMessage` gates the
+ * restore-confirm flow (thread/index.tsx), and `onTranscribeAudio` gates voice
+ * recording/conversation (use-voice-recorder, use-voice-conversation). An
+ * unconditional arrow wrapper is always truthy, which would render a dead
+ * dismiss button and let voice recording proceed with no transcription backend.
+ * So wrap an optional field only when it is currently present, and re-read the
+ * latest value inside the wrapper for the stale-closure fix.
  */
+function latestOptional<A extends unknown[], R>(
+  read: () => ((...args: A) => R) | undefined
+): ((...args: A) => R) | undefined {
+  // Presence is sampled from the object identity the surface currently holds.
+  // The controller mutates fields in place rather than swapping a handler
+  // between defined and undefined, so presence is stable for a given actions
+  // object while the *closure* is what churns — which is exactly what the
+  // indirection below re-reads.
+  return read() ? (...args: A) => read()!(...args) : undefined
+}
+
 export function latestChatActions(actions: ChatActions): ChatActions {
   return {
     onAddContextRef: (...args) => actions.onAddContextRef(...args),
@@ -16,7 +37,7 @@ export function latestChatActions(actions: ChatActions): ChatActions {
     onBranchInNewChat: (...args) => actions.onBranchInNewChat(...args),
     onCancel: (...args) => actions.onCancel(...args),
     onDeleteSelectedSession: (...args) => actions.onDeleteSelectedSession(...args),
-    onDismissError: (...args) => actions.onDismissError?.(...args),
+    onDismissError: latestOptional(() => actions.onDismissError),
     onEdit: (...args) => actions.onEdit(...args),
     onPasteClipboardImage: (...args) => actions.onPasteClipboardImage(...args),
     onPickFiles: (...args) => actions.onPickFiles(...args),
@@ -24,13 +45,13 @@ export function latestChatActions(actions: ChatActions): ChatActions {
     onPickImages: (...args) => actions.onPickImages(...args),
     onReload: (...args) => actions.onReload(...args),
     onRemoveAttachment: (...args) => actions.onRemoveAttachment(...args),
-    onRestoreToMessage: (...args) => actions.onRestoreToMessage?.(...args) ?? Promise.resolve(),
+    onRestoreToMessage: latestOptional(() => actions.onRestoreToMessage),
     onRetryResume: (...args) => actions.onRetryResume(...args),
     onSteer: (...args) => actions.onSteer(...args),
     onSubmit: (...args) => actions.onSubmit(...args),
     onThreadMessagesChange: (...args) => actions.onThreadMessagesChange(...args),
     onToggleSelectedPin: (...args) => actions.onToggleSelectedPin(...args),
-    onTranscribeAudio: (...args) => actions.onTranscribeAudio?.(...args) ?? Promise.resolve('')
+    onTranscribeAudio: latestOptional(() => actions.onTranscribeAudio)
   }
 }
 
@@ -39,8 +60,8 @@ export function latestSidebarActions(actions: SidebarActions): SidebarActions {
     onArchiveSession: (...args) => actions.onArchiveSession(...args),
     onBranchSession: (...args) => actions.onBranchSession(...args),
     onDeleteSession: (...args) => actions.onDeleteSession(...args),
-    onLoadMoreMessaging: (...args) => actions.onLoadMoreMessaging?.(...args),
-    onLoadMoreProfileSessions: (...args) => actions.onLoadMoreProfileSessions?.(...args),
+    onLoadMoreMessaging: latestOptional(() => actions.onLoadMoreMessaging),
+    onLoadMoreProfileSessions: latestOptional(() => actions.onLoadMoreProfileSessions),
     onLoadMoreSessions: (...args) => actions.onLoadMoreSessions(...args),
     onManageCronJob: (...args) => actions.onManageCronJob(...args),
     onNavigate: (...args) => actions.onNavigate(...args),

apps/desktop/src/app/contrib/surfaces.tsx

@@ -141,6 +141,7 @@ export const ChatRoutesSurface = memo(function ChatRoutesSurface({
   )
 
   const chatActions = useMemo(() => latestChatActions(actions), [actions])
+
   const chatView = (
     <ChatView
       gateway={gateway}

contributors/emails/eagleyouxiang@gmail.com

@@ -0,0 +1 @@
+eagle-nyp

contributors/emails/nypyouxiang@163.com

@@ -0,0 +1 @@
+eagle-nyp