Key pending follow-output by terminal leaf

Co-authored-by: Orca <help@stably.ai>

src/renderer/src/components/terminal-pane/focus-terminal-pane-event.test.ts

@@ -92,7 +92,7 @@ describe('handleFocusTerminalPaneDetail', () => {
     )
 
     expect(manager.setActivePane).toHaveBeenCalledWith(7, { focus: true })
-    expect(scrollToBottomIfOutputSinceLastView).toHaveBeenCalledWith(7)
+    expect(scrollToBottomIfOutputSinceLastView).toHaveBeenCalledWith(LEAF_ID)
   })
 
   it('does not focus, flash, or ack when the numeric pane no longer owns the leaf', () => {

src/renderer/src/components/terminal-pane/focus-terminal-pane-event.ts

@@ -14,7 +14,7 @@ type FocusTerminalPaneEventDeps = {
   manager: FocusTerminalPaneManager | null
   acknowledgeAgents: (paneKeys: string[]) => void
   surfaceStaleAgentRow: (tabId: string, leafId: string) => void
-  scrollToBottomIfOutputSinceLastView?: (paneId: number) => void
+  scrollToBottomIfOutputSinceLastView?: (leafId: ManagedPane['leafId']) => void
 }
 
 export function handleFocusTerminalPaneDetail(
@@ -48,7 +48,7 @@ export function handleFocusTerminalPaneDetail(
   }
   manager.setActivePane(resolution.numericPaneId, { focus: true })
   if (detail.scrollToBottomIfOutputSinceLastView) {
-    scrollToBottomIfOutputSinceLastView?.(resolution.numericPaneId)
+    scrollToBottomIfOutputSinceLastView?.(resolution.leafId)
   }
   if (detail.flashFocusedPane) {
     const pane = manager.getPanes().find((candidate) => candidate.id === resolution.numericPaneId)

src/renderer/src/components/terminal-pane/use-terminal-scroll-visibility-memory.test.ts

@@ -115,7 +115,7 @@ describe('useTerminalScrollVisibilityMemory', () => {
       paneCount: 1
     })
 
-    visibilityMemory.scheduleFollowOutputIfNeeded(1)
+    visibilityMemory.scheduleFollowOutputIfNeeded('leaf-1' as never)
     animationFrames.shift()?.(16)
     animationFrames.shift()?.(32)
 
@@ -145,7 +145,7 @@ describe('useTerminalScrollVisibilityMemory', () => {
       paneCount: 1
     })
 
-    visibilityMemory.scheduleFollowOutputIfNeeded(1)
+    visibilityMemory.scheduleFollowOutputIfNeeded('leaf-1' as never)
     runEffectCleanups()
 
     expect(cancelAnimationFrame).toHaveBeenCalledWith(7)
@@ -243,4 +243,84 @@ describe('useTerminalScrollVisibilityMemory', () => {
     )
     expect(mocks.captureScrollState).toHaveBeenCalledTimes(2)
   })
+
+  it('does not apply pending follow-output to a reused pane id with a different leaf', () => {
+    const oldTerminal = {
+      onScroll: vi.fn(() => ({ dispose: vi.fn() })),
+      scrollToBottom: vi.fn()
+    }
+    const newTerminal = {
+      onScroll: vi.fn(() => ({ dispose: vi.fn() })),
+      scrollToBottom: vi.fn()
+    }
+    let panes = [{ id: 1, leafId: 'old-leaf', terminal: oldTerminal }]
+    const manager = {
+      getPanes: vi.fn(() => panes)
+    }
+    const animationFrames: FrameRequestCallback[] = []
+    globalThis.requestAnimationFrame = vi.fn((callback: FrameRequestCallback) => {
+      animationFrames.push(callback)
+      return animationFrames.length
+    })
+
+    beginHookRender()
+    const visibilityMemory = useTerminalScrollVisibilityMemory({
+      managerRef: { current: manager as never },
+      isVisibleRef: { current: true },
+      visibleResumeCompleteRef: { current: true },
+      paneCount: 1
+    })
+
+    visibilityMemory.scheduleFollowOutputIfNeeded('old-leaf' as never)
+    panes = [{ id: 1, leafId: 'new-leaf', terminal: newTerminal }]
+    animationFrames.shift()?.(16)
+    animationFrames.shift()?.(32)
+
+    expect(oldTerminal.scrollToBottom).not.toHaveBeenCalled()
+    expect(newTerminal.scrollToBottom).not.toHaveBeenCalled()
+    expect(mocks.flushTerminalOutput).not.toHaveBeenCalled()
+  })
+
+  it('does not follow output when the remembered visible position was not at bottom', () => {
+    const onScrollListeners: (() => void)[] = []
+    const terminal = {
+      onScroll: vi.fn((listener: () => void) => {
+        onScrollListeners.push(listener)
+        return { dispose: vi.fn() }
+      }),
+      scrollToBottom: vi.fn()
+    }
+    const manager = {
+      getPanes: vi.fn(() => [{ id: 1, leafId: 'leaf-1', terminal }])
+    }
+    const animationFrames: FrameRequestCallback[] = []
+    globalThis.requestAnimationFrame = vi.fn((callback: FrameRequestCallback) => {
+      animationFrames.push(callback)
+      return animationFrames.length
+    })
+    mocks.captureScrollState.mockReturnValue({
+      bufferType: 'normal',
+      wasAtBottom: false,
+      viewportY: 42,
+      baseY: 100
+    })
+
+    beginHookRender()
+    const visibilityMemory = useTerminalScrollVisibilityMemory({
+      managerRef: { current: manager as never },
+      isVisibleRef: { current: true },
+      visibleResumeCompleteRef: { current: true },
+      paneCount: 1
+    })
+    onScrollListeners[0]?.()
+
+    visibilityMemory.scheduleFollowOutputIfNeeded('leaf-1' as never)
+    animationFrames.shift()?.(16)
+    animationFrames.shift()?.(32)
+
+    expect(mocks.flushTerminalOutput).toHaveBeenCalledWith(terminal, {
+      maxChars: 256 * 1024
+    })
+    expect(terminal.scrollToBottom).not.toHaveBeenCalled()
+  })
 })

src/renderer/src/components/terminal-pane/use-terminal-scroll-visibility-memory.ts

@@ -28,7 +28,7 @@ type TerminalScrollVisibilityMemory = {
   ) => Map<ManagedPane['leafId'], ScrollState>
   withSuppressedScrollTracking: (callback: () => void) => void
   applyPendingFollowOutputRequests: () => boolean
-  scheduleFollowOutputIfNeeded: (paneId: number) => void
+  scheduleFollowOutputIfNeeded: (leafId: ManagedPane['leafId']) => void
 }
 
 const FOLLOW_OUTPUT_FLUSH_CHARS = 256 * 1024
@@ -44,7 +44,7 @@ export function useTerminalScrollVisibilityMemory({
   )
   const scrollDisposablesRef = useRef<Map<ManagedPane['leafId'], IDisposable>>(new Map())
   const suppressScrollTrackingRef = useRef(false)
-  const pendingFollowOutputPaneIdsRef = useRef<Set<number>>(new Set())
+  const pendingFollowOutputLeafIdsRef = useRef<Set<ManagedPane['leafId']>>(new Set())
   const followOutputFrameIdsRef = useRef<number[]>([])
 
   const captureVisibleScrollSnapshot = useCallback(
@@ -98,7 +98,7 @@ export function useTerminalScrollVisibilityMemory({
   }, [])
 
   const applyPendingFollowOutputRequests = useCallback((): boolean => {
-    const pending = pendingFollowOutputPaneIdsRef.current
+    const pending = pendingFollowOutputLeafIdsRef.current
     if (pending.size === 0) {
       return false
     }
@@ -111,7 +111,7 @@ export function useTerminalScrollVisibilityMemory({
     }
     let didScroll = false
     for (const pane of manager.getPanes()) {
-      if (!pending.has(pane.id)) {
+      if (!pending.has(pane.leafId)) {
         continue
       }
       const previous = visibleScrollSnapshotsRef.current.get(pane.leafId)
@@ -121,13 +121,13 @@ export function useTerminalScrollVisibilityMemory({
       flushTerminalOutput(pane.terminal, { maxChars: FOLLOW_OUTPUT_FLUSH_CHARS })
       const currentEpoch = getTerminalOutputEpoch(pane.terminal)
       const hasNewOutput = previous ? currentEpoch > previous.outputEpoch : currentEpoch > 0
-      if (hasNewOutput) {
+      if (hasNewOutput && (previous?.scrollState.wasAtBottom ?? true)) {
         cancelDeferredScrollRestore(pane.terminal)
         pane.terminal.scrollToBottom()
         rememberVisibleScrollSnapshot(pane.leafId, pane.terminal)
         didScroll = true
       }
-      pending.delete(pane.id)
+      pending.delete(pane.leafId)
     }
     return didScroll
   }, [isVisibleRef, managerRef, rememberVisibleScrollSnapshot, visibleResumeCompleteRef])
@@ -140,8 +140,8 @@ export function useTerminalScrollVisibilityMemory({
   }, [])
 
   const scheduleFollowOutputIfNeeded = useCallback(
-    (paneId: number): void => {
-      pendingFollowOutputPaneIdsRef.current.add(paneId)
+    (leafId: ManagedPane['leafId']): void => {
+      pendingFollowOutputLeafIdsRef.current.add(leafId)
       if (followOutputFrameIdsRef.current.length > 0) {
         return
       }