fix: keep codex redraws off pty batch path (#3992)

src/main/ipc/pty.test.ts

@@ -3266,6 +3266,40 @@ describe('registerPtyHandlers', () => {
     }
   })
 
+  it('sends larger ANSI redraws immediately after terminal input', async () => {
+    vi.useFakeTimers()
+    const mockProc = createMockProc()
+    spawnMock.mockReturnValue(mockProc.proc)
+
+    try {
+      registerPtyHandlers(mainWindow as never)
+      const spawnResult = (await handlers.get('pty:spawn')!(null, {
+        cols: 80,
+        rows: 24,
+        cwd: '/tmp'
+      })) as { id: string }
+      const writeListener = getPtyWriteListener()
+
+      writeListener(null, {
+        id: spawnResult.id,
+        data: 'a'
+      })
+      mainWindow.webContents.send.mockClear()
+
+      const redraw = `\x1b[2J\x1b[H${'codex composer redraw '.repeat(80)}`
+      mockProc.emitData(redraw)
+
+      expect(mainWindow.webContents.send).toHaveBeenCalledWith('pty:data', {
+        id: spawnResult.id,
+        data: redraw
+      })
+      vi.advanceTimersByTime(8)
+      expect(mainWindow.webContents.send).toHaveBeenCalledTimes(1)
+    } finally {
+      vi.useRealTimers()
+    }
+  })
+
   it('batches combined pending output that exceeds the interactive size limit', async () => {
     vi.useFakeTimers()
     const mockProc = createMockProc()

src/main/ipc/pty.ts

@@ -946,12 +946,23 @@ export function registerPtyHandlers(
   // large output and non-interactive output must still use the batcher.
   const INTERACTIVE_OUTPUT_WINDOW_MS = 100
   const INTERACTIVE_OUTPUT_MAX_CHARS = 1024
+  const INTERACTIVE_REDRAW_MAX_CHARS = PTY_BATCH_FLUSH_CHUNK_CHARS
   const BACKGROUND_OUTPUT_INPUT_QUIET_MS = 50
   const BACKGROUND_OUTPUT_MAX_INPUT_HOLD_MS = 250
   let lastRendererInputAt = Number.NEGATIVE_INFINITY
   let lastRendererInputPtyId: string | null = null
   let backgroundFlushHeldSince: number | null = null
 
+  function isLikelyInteractiveRedraw(data: string): boolean {
+    if (data.length <= INTERACTIVE_OUTPUT_MAX_CHARS) {
+      return true
+    }
+    // Why: Codex-style TUIs can repaint more than 1 KB per keypress. ANSI
+    // control redraws are still latency-sensitive, while plain command output
+    // should stay on the throughput batch path.
+    return data.length <= INTERACTIVE_REDRAW_MAX_CHARS && data.includes('\x1b[')
+  }
+
   function getChunkStartSeq(endSeq: number | undefined, data: string): number | undefined {
     return typeof endSeq === 'number' ? Math.max(0, endSeq - data.length) : undefined
   }
@@ -1176,7 +1187,7 @@ export function registerPtyHandlers(
       const nextData = pending.data
       const lastInputAt = lastInputAtByPty.get(payload.id)
       const isInteractiveOutput =
-        nextData.length <= INTERACTIVE_OUTPUT_MAX_CHARS &&
+        isLikelyInteractiveRedraw(nextData) &&
         lastInputAt !== undefined &&
         performance.now() - lastInputAt <= INTERACTIVE_OUTPUT_WINDOW_MS
       if (isInteractiveOutput) {