fix(terminal): reject stale pane transport callbacks

src/renderer/src/components/terminal-pane/pty-connection-pty-exit-teardown.test.ts

@@ -735,7 +735,11 @@ describe('connectPanePty', () => {
     // The fixture dependency is intentionally lightweight, so mirror the live
     // tab/layout commit that the real store performs atomically on replacement.
     mockStoreState.tabsByWorktree['wt-1'][0]!.ptyId = 'terminal-reconnected'
-    mockStoreState.terminalLayoutsByTabId['tab-1']!.ptyIdsByLeafId![LEAF_1] = 'terminal-reconnected'
+    const replacementLayout = mockStoreState.terminalLayoutsByTabId?.['tab-1']
+    if (!replacementLayout) {
+      throw new Error('test fixture missing terminal layout')
+    }
+    replacementLayout.ptyIdsByLeafId![LEAF_1] = 'terminal-reconnected'
 
     onPtySpawn?.('terminal-old')
 
@@ -743,6 +747,87 @@ describe('connectPanePty', () => {
     expect(deps.syncPanePtyLayoutBinding).not.toHaveBeenLastCalledWith(1, 'terminal-old')
   })
 
+  it('ignores a late split-pane spawn callback when the tab identity belongs to pane one', async () => {
+    const { connectPanePty } = await import('./pty-connection')
+    let transportPtyId = 'terminal-old'
+    const transport = createMockTransport(transportPtyId)
+    transport.getPtyId = vi.fn(() => transportPtyId)
+    transportFactoryQueue.push(transport)
+    const manager = createManager(2, 2)
+    const deps = createDeps()
+    const pane = createPane(2)
+    mockStoreState.terminalLayoutsByTabId = {
+      'tab-1': {
+        root: {
+          type: 'split',
+          direction: 'horizontal',
+          first: { type: 'leaf', leafId: LEAF_1 },
+          second: { type: 'leaf', leafId: LEAF_2 },
+          ratio: 0.5
+        },
+        activeLeafId: LEAF_2,
+        expandedLeafId: null,
+        ptyIdsByLeafId: { [LEAF_1]: 'tab-pty', [LEAF_2]: 'terminal-old' }
+      }
+    }
+
+    connectPanePty(pane as never, manager as never, deps as never)
+    const onPtySpawn = createdTransportOptions[0]?.onPtySpawn as
+      | ((ptyId: string) => void)
+      | undefined
+    const onPtyRebind = createdTransportOptions[0]?.onPtyRebind as
+      | ((ptyId: string, replacedPtyId: string) => void)
+      | undefined
+    expect(onPtySpawn).toBeTypeOf('function')
+    expect(onPtyRebind).toBeTypeOf('function')
+
+    onPtySpawn?.('terminal-old')
+    transportPtyId = 'terminal-reconnected'
+    onPtyRebind?.('terminal-reconnected', 'terminal-old')
+
+    // The tab-level PTY is pane one's fallback; pane two is represented by its leaf binding.
+    expect(mockStoreState.tabsByWorktree['wt-1'][0]?.ptyId).toBe('tab-pty')
+    expect(mockStoreState.terminalLayoutsByTabId?.['tab-1']?.ptyIdsByLeafId?.[LEAF_2]).toBe(
+      'terminal-reconnected'
+    )
+
+    onPtySpawn?.('terminal-old')
+
+    expect(pane.container.dataset.ptyId).toBe('terminal-reconnected')
+    expect(deps.syncPanePtyLayoutBinding).not.toHaveBeenLastCalledWith(2, 'terminal-old')
+  })
+
+  it('accepts a fresh spawn when the persisted pane still names the retired PTY', async () => {
+    const { connectPanePty } = await import('./pty-connection')
+    let transportPtyId = 'terminal-new'
+    const transport = createMockTransport(transportPtyId)
+    transport.getPtyId = vi.fn(() => transportPtyId)
+    transportFactoryQueue.push(transport)
+    const manager = createManager(1)
+    const deps = createDeps()
+    const pane = createPane(1)
+    mockStoreState.tabsByWorktree['wt-1'] = [{ id: 'tab-1', ptyId: 'terminal-old' }]
+    const terminalLayoutsByTabId =
+      mockStoreState.terminalLayoutsByTabId ?? (mockStoreState.terminalLayoutsByTabId = {})
+    terminalLayoutsByTabId['tab-1'] = {
+      root: { type: 'leaf', leafId: LEAF_1 },
+      activeLeafId: LEAF_1,
+      expandedLeafId: null,
+      ptyIdsByLeafId: { [LEAF_1]: 'terminal-old' }
+    }
+
+    connectPanePty(pane as never, manager as never, deps as never)
+    const onPtySpawn = createdTransportOptions[0]?.onPtySpawn as
+      | ((ptyId: string) => void)
+      | undefined
+    expect(onPtySpawn).toBeTypeOf('function')
+
+    onPtySpawn?.('terminal-new')
+
+    expect(pane.container.dataset.ptyId).toBe('terminal-new')
+    expect(deps.syncPanePtyLayoutBinding).toHaveBeenLastCalledWith(1, 'terminal-new')
+  })
+
   it('closes a split pane when an established PTY exits after output', async () => {
     const { connectPanePty } = await import('./pty-connection')
     const capturedDataCallback: { current: ((data: string) => void) | null } = { current: null }

src/renderer/src/components/terminal-pane/pty-connection/pane-pty-visibility-bind.ts

@@ -49,12 +49,20 @@ export function installPanePtyVisibilityBind(session: ConnectPanePtySession): vo
       const tabPtyId = Object.values(state.tabsByWorktree)
         .flat()
         .find((tab) => tab.id === session.deps.tabId)?.ptyId
+      const activePtyId = session.activePanePtyBinding
+      const isCurrentPaneTransport =
+        session.deps.paneTransportsRef.current.get(session.pane.id) === session.transport
+      const isStaleTransportBinding =
+        !isCurrentPaneTransport || (activePtyId !== null && session.transport.getPtyId() !== ptyId)
+      const isInitialCurrentTransportBinding = isCurrentPaneTransport && activePtyId === null
       if (
-        shouldIgnoreStalePanePtyLayoutBinding({
+        isStaleTransportBinding ||
+        (shouldIgnoreStalePanePtyLayoutBinding({
           existingPtyId,
           nextPtyId: ptyId,
           tabPtyId
-        })
+        }) &&
+          !isInitialCurrentTransportBinding)
       ) {
         return
       }

src/renderer/src/components/terminal-pane/pty-connection/reattach-result-handler.ts

@@ -23,6 +23,8 @@ type ReattachResultSession = ReattachPayloadSession &
   Pick<
     ConnectPanePtySession,
     | 'agentCompletionCoordinator'
+    | 'activePanePtyBinding'
+    | 'activePanePtyBindingBoundAt'
     | 'authoritativeReattachGeneration'
     | 'capturedDirectSshRetryPtyAccepted'
     | 'cacheKey'
@@ -168,6 +170,10 @@ export function bindHandleReattachResult(sessionBag: ConnectPanePtySession): voi
       return false
     }
     session.setPanePtyFitBinding(ptyId)
+    // Keep the session-local identity in step with the transport before any
+    // queued spawn callback can arrive during replay.
+    session.activePanePtyBinding = ptyId
+    session.activePanePtyBindingBoundAt = performance.now()
     session.reportPanePtyVisibility(ptyId, session.deps.isVisibleRef.current)
     session.registerSideEffectFactConsumerForPty(ptyId)
     session.syncHiddenRendererPtyDelivery()