Preserve pending terminal restore on fast hide

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

src/renderer/src/components/terminal-pane/TerminalPane.tsx

@@ -72,7 +72,11 @@ import {
 } from '@/lib/pane-manager/mobile-driver-state'
 import { resolvePaneKeyForManager } from '@/lib/pane-manager/pane-key-resolution'
 import { safeFit } from '@/lib/pane-manager/pane-tree-ops'
-import { captureScrollState, restoreScrollStateAfterLayout } from '@/lib/pane-manager/pane-scroll'
+import {
+  captureScrollState,
+  getPendingScrollRestoreState,
+  restoreScrollStateAfterLayout
+} from '@/lib/pane-manager/pane-scroll'
 import {
   logTerminalScrollRestore,
   terminalScrollStateForDebug,
@@ -730,7 +734,8 @@ export default function TerminalPane({
     const scrollStatesByLeafId = isVisibleRef.current
       ? Object.fromEntries(
           currentPanes.map((pane) => {
-            const { bufferType, wasAtBottom, viewportY, baseY } = captureScrollState(pane.terminal)
+            const { bufferType, wasAtBottom, viewportY, baseY } =
+              getPendingScrollRestoreState(pane.terminal) ?? captureScrollState(pane.terminal)
             const current = { bufferType, wasAtBottom, viewportY, baseY }
             const previous = lastVisibleScrollStatesByLeafIdRef.current?.[pane.leafId]
             const stable =
@@ -861,7 +866,8 @@ export default function TerminalPane({
     }
     return Object.fromEntries(
       manager.getPanes().map((pane) => {
-        const { bufferType, wasAtBottom, viewportY, baseY } = captureScrollState(pane.terminal)
+        const { bufferType, wasAtBottom, viewportY, baseY } =
+          getPendingScrollRestoreState(pane.terminal) ?? captureScrollState(pane.terminal)
         const current = { bufferType, wasAtBottom, viewportY, baseY }
         const previous = lastVisibleScrollStatesByLeafIdRef.current?.[pane.leafId]
         const stable =

src/renderer/src/components/terminal-pane/use-terminal-pane-global-effects.test.ts

@@ -15,6 +15,7 @@ const mocks = vi.hoisted(() => ({
   fitPanes: vi.fn(),
   focusActivePane: vi.fn(),
   flushTerminalOutput: vi.fn(),
+  getPendingScrollRestoreState: vi.fn(() => null),
   getTerminalOutputEpoch: vi.fn(() => 0),
   handleTerminalFileDrop: vi.fn(),
   pasteTerminalText: vi.fn(),
@@ -70,6 +71,7 @@ vi.mock('@/lib/pane-manager/pane-terminal-output-scheduler', () => ({
 
 vi.mock('@/lib/pane-manager/pane-scroll', () => ({
   captureScrollState: mocks.captureScrollState,
+  getPendingScrollRestoreState: mocks.getPendingScrollRestoreState,
   getTerminalOutputEpoch: mocks.getTerminalOutputEpoch,
   restoreScrollState: mocks.restoreScrollState,
   restoreScrollStateAfterLayout: mocks.restoreScrollStateAfterLayout

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

@@ -11,6 +11,7 @@ const mocks = vi.hoisted(() => ({
     baseY: 0
   })),
   flushTerminalOutput: vi.fn(),
+  getPendingScrollRestoreState: vi.fn((): unknown => null),
   getTerminalOutputEpoch: vi.fn(() => 1),
   isTerminalScrollRestoreInProgress: vi.fn(() => false)
 }))
@@ -66,6 +67,7 @@ vi.mock('@/lib/pane-manager/pane-terminal-output-scheduler', () => ({
 vi.mock('@/lib/pane-manager/pane-scroll', () => ({
   cancelDeferredScrollRestore: mocks.cancelDeferredScrollRestore,
   captureScrollState: mocks.captureScrollState,
+  getPendingScrollRestoreState: mocks.getPendingScrollRestoreState,
   getTerminalOutputEpoch: mocks.getTerminalOutputEpoch,
   isTerminalScrollRestoreInProgress: mocks.isTerminalScrollRestoreInProgress
 }))
@@ -78,6 +80,7 @@ describe('useTerminalScrollVisibilityMemory', () => {
     resetHookRefs()
     vi.clearAllMocks()
     mocks.captureScrollState.mockReset()
+    mocks.getPendingScrollRestoreState.mockReset()
     mocks.getTerminalOutputEpoch.mockReset()
     mocks.isTerminalScrollRestoreInProgress.mockReset()
     mocks.captureScrollState.mockImplementation(() => ({
@@ -86,6 +89,7 @@ describe('useTerminalScrollVisibilityMemory', () => {
       viewportY: 0,
       baseY: 0
     }))
+    mocks.getPendingScrollRestoreState.mockImplementation(() => null)
     mocks.getTerminalOutputEpoch.mockImplementation(() => 1)
     mocks.isTerminalScrollRestoreInProgress.mockImplementation(() => false)
   })
@@ -256,6 +260,40 @@ describe('useTerminalScrollVisibilityMemory', () => {
     )
   })
 
+  it('captures the pending restore target while a visibility restore is settling', () => {
+    const terminal = {
+      onScroll: vi.fn(() => ({ dispose: vi.fn() }))
+    }
+    const manager = {
+      getPanes: vi.fn(() => [{ id: 1, leafId: 'leaf-1', terminal }])
+    }
+    const pendingRestoreState = {
+      bufferType: 'normal',
+      wasAtBottom: false,
+      viewportY: 150,
+      baseY: 154
+    }
+    mocks.getPendingScrollRestoreState.mockReturnValue(pendingRestoreState)
+    mocks.captureScrollState.mockReturnValue({
+      bufferType: 'normal',
+      wasAtBottom: false,
+      viewportY: 56,
+      baseY: 154
+    })
+
+    beginHookRender()
+    const visibilityMemory = useTerminalScrollVisibilityMemory({
+      managerRef: { current: manager as never },
+      isVisibleRef: { current: true },
+      visibleResumeCompleteRef: { current: true },
+      paneCount: 1
+    })
+
+    expect(visibilityMemory.captureViewportPositions(false).get('leaf-1' as never)).toBe(
+      pendingRestoreState
+    )
+  })
+
   it('does not reuse a remembered snapshot when a pane id gets a new leaf', () => {
     const terminal = {
       onScroll: vi.fn(() => ({ dispose: vi.fn() }))

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

@@ -4,6 +4,7 @@ import { flushTerminalOutput } from '@/lib/pane-manager/pane-terminal-output-sch
 import {
   cancelDeferredScrollRestore,
   captureScrollState,
+  getPendingScrollRestoreState,
   getTerminalOutputEpoch,
   isTerminalScrollRestoreInProgress
 } from '@/lib/pane-manager/pane-scroll'
@@ -84,7 +85,8 @@ export function useTerminalScrollVisibilityMemory({
           if (useRememberedSnapshots && remembered) {
             return [pane.leafId, remembered.scrollState] as const
           }
-          const state = captureScrollState(pane.terminal)
+          const state =
+            getPendingScrollRestoreState(pane.terminal) ?? captureScrollState(pane.terminal)
           const stableState =
             remembered && isTransientTerminalEdgeSnap(state, remembered.scrollState)
               ? remembered.scrollState

src/renderer/src/lib/pane-manager/pane-scroll.ts

@@ -37,6 +37,10 @@ export function isTerminalScrollRestoreInProgress(terminal: Terminal): boolean {
   return (terminalScrollRestoreDepths.get(terminal) ?? 0) > 0
 }
 
+export function getPendingScrollRestoreState(terminal: Terminal): ScrollState | null {
+  return deferredScrollRestores.get(terminal)?.state ?? null
+}
+
 export function cancelDeferredScrollRestore(terminal: Terminal): void {
   const pending = deferredScrollRestores.get(terminal)
   if (!pending) {