Fix Windows terminal clear repaint (#6382)

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

@@ -779,14 +779,37 @@ export default function TerminalPane({
   const clearPaneScrollback = useCallback(
     (pane: ManagedPane): void => {
       clearedScrollbackLeafIdsRef.current.add(pane.leafId)
+      const transport = paneTransportsRef.current.get(pane.id)
+      const ptyId = transport?.getPtyId() ?? null
       pane.terminal.clear()
-      // Why: also clear the host buffer for remote-server panes, or the next
-      // host snapshot replays the scrollback we just cleared locally.
-      const ptyId = paneTransportsRef.current.get(pane.id)?.getPtyId() ?? null
       clearWebRuntimeTerminalBuffer(ptyId)
-      persistLayoutSnapshot()
+      const isRemoteRuntimePty = typeof ptyId === 'string' && isRemoteRuntimePtyId(ptyId)
+      const shouldRepairWindowsClear =
+        isWindowsUserAgent() && getConnectionId(worktreeId) === null && !isRemoteRuntimePty
+      const repairWindowsClear = (): void => {
+        if (!shouldRepairWindowsClear) {
+          return
+        }
+        // Why: local Windows xterm can keep wrapped prompt/cursor paint stale
+        // after clear; keep this frontend-only so ConPTY does not repaint it.
+        safeFit(pane)
+        pane.terminal.refresh(0, Math.max(0, pane.terminal.rows - 1))
+        requestAnimationFrame(() => {
+          if (!managerRef.current?.getPanes().some((livePane) => livePane.id === pane.id)) {
+            return
+          }
+          safeFit(pane)
+          pane.terminal.refresh(0, Math.max(0, pane.terminal.rows - 1))
+        })
+      }
+      // Why: provider/session buffers can outlive the visible xterm. Clear
+      // them through the same contract used by remote/mobile terminal state.
+      void Promise.resolve(transport?.clearBuffer?.()).finally(() => {
+        repairWindowsClear()
+        persistLayoutSnapshot()
+      })
     },
-    [paneTransportsRef, persistLayoutSnapshot]
+    [paneTransportsRef, persistLayoutSnapshot, worktreeId]
   )
 
   useEffect(() => {

src/renderer/src/components/terminal-pane/pty-dispatcher.ts

@@ -363,6 +363,7 @@ export type PtyTransport = {
   getPtyId: () => string | null
   getConnectionId?: () => string | null | undefined
   getLocalSessionMetadata?: () => LocalPtySessionMetadata | null
+  clearBuffer?: () => Promise<void>
   serializeBuffer?: (opts?: { scrollbackRows?: number }) => Promise<PtyBufferSnapshot | null>
   preserve?: () => void
   /** Unregister PTY handlers without killing the process for pane remounts. */

src/renderer/src/components/terminal-pane/pty-transport.test.ts

@@ -42,6 +42,7 @@ describe('createIpcPtyTransport', () => {
           writeAccepted: vi.fn().mockResolvedValue(true),
           resize: vi.fn(),
           kill: vi.fn(),
+          clearBuffer: vi.fn().mockResolvedValue(undefined),
           onData: vi.fn((callback: (payload: { id: string; data: string }) => void) => {
             onData = callback
             return () => {}
@@ -163,6 +164,20 @@ describe('createIpcPtyTransport', () => {
     expect(sshTransport.getLocalSessionMetadata?.()).toBeNull()
   })
 
+  it('clears the connected PTY buffer through the preload API', async () => {
+    const { createIpcPtyTransport } = await import('./pty-transport')
+    const transport = createIpcPtyTransport({})
+
+    await transport.clearBuffer?.()
+    expect(window.api.pty.clearBuffer).not.toHaveBeenCalled()
+
+    await transport.connect({ url: '', callbacks: {} })
+    await transport.clearBuffer?.()
+
+    expect(window.api.pty.clearBuffer).toHaveBeenCalledWith('pty-1')
+    transport.disconnect()
+  })
+
   it('defers title side effects until after terminal data is delivered', async () => {
     const { createIpcPtyTransport } = await import('./pty-transport')
     const onTitleChange = vi.fn()

src/renderer/src/components/terminal-pane/pty-transport.ts

@@ -967,6 +967,13 @@ export function createIpcPtyTransport(opts: IpcPtyTransportOptions = {}): PtyTra
       }
     },
 
+    async clearBuffer() {
+      if (!connected || !ptyId) {
+        return
+      }
+      await window.api.pty.clearBuffer(ptyId)
+    },
+
     destroy() {
       destroyed = true
       this.disconnect()

src/renderer/src/web/web-preload-api.ts

@@ -2445,6 +2445,7 @@ function createPtyApi(): NonNullable<Partial<PreloadApi>['pty']> {
     onSerializeBufferRequest: () => noopUnsubscribe,
     onClearBufferRequest: () => noopUnsubscribe,
     sendSerializedBuffer: () => {},
+    clearBuffer: () => Promise.resolve(),
     declarePendingPaneSerializer: () => Promise.resolve(0),
     settlePaneSerializer: () => Promise.resolve(),
     clearPendingPaneSerializer: () => Promise.resolve(),