From 2f7fe087a2a0f474ba68267ef2b07ea88010fd04 Mon Sep 17 00:00:00 2001
From: Jinwoo Hong <73622457+Jinwoo-H@users.noreply.github.com>
Date: Sat, 6 Jun 2026 00:16:40 -0400
Subject: [PATCH] Fix Codex held-key input batching (#4732)

---
 .../pane-terminal-output-scheduler.test.ts    | 49 ++++++++++++++++++-
 .../pane-terminal-output-scheduler.ts         |  4 +-
 2 files changed, 50 insertions(+), 3 deletions(-)

diff --git a/src/renderer/src/lib/pane-manager/pane-terminal-output-scheduler.test.ts b/src/renderer/src/lib/pane-manager/pane-terminal-output-scheduler.test.ts
index 07acbb59541..63c205ff3e4 100644
--- a/src/renderer/src/lib/pane-manager/pane-terminal-output-scheduler.test.ts
+++ b/src/renderer/src/lib/pane-manager/pane-terminal-output-scheduler.test.ts
@@ -298,7 +298,7 @@ describe('pane terminal output scheduler', () => {
       stripTransientCursorShows: true
     })
 
-    vi.advanceTimersByTime(31)
+    vi.advanceTimersByTime(15)
     expect(terminal.write).not.toHaveBeenCalled()
 
     vi.advanceTimersByTime(1)
@@ -328,7 +328,7 @@ describe('pane terminal output scheduler', () => {
       coalesceForeground: true
     })
 
-    vi.advanceTimersByTime(31)
+    vi.advanceTimersByTime(15)
     expect(terminal.write).not.toHaveBeenCalled()
 
     vi.advanceTimersByTime(1)
@@ -340,6 +340,51 @@ describe('pane terminal output scheduler', () => {
     )
   })
 
+  it('does not batch repeated latency-sensitive synchronized frames across key-repeat ticks', async () => {
+    vi.useFakeTimers()
+    const { writeTerminalOutput } = await loadScheduler()
+    const terminal = createTerminal()
+
+    writeTerminalOutput(terminal, '\x1b[?2026h\x1b[0 q\x1b[?25l\x1b[19;3Hx\x1b[?25h', {
+      foreground: true,
+      latencySensitive: true,
+      stripTransientCursorShows: true,
+      holdForeground: true
+    })
+    writeTerminalOutput(terminal, '\x1b[?2026l', {
+      foreground: true,
+      latencySensitive: true,
+      stripTransientCursorShows: true,
+      coalesceForeground: true
+    })
+
+    vi.advanceTimersByTime(16)
+    vi.runOnlyPendingTimers()
+    expect(terminal.write).toHaveBeenCalledTimes(1)
+
+    writeTerminalOutput(terminal, '\x1b[?2026h\x1b[0 q\x1b[?25l\x1b[19;4Hx\x1b[?25h', {
+      foreground: true,
+      latencySensitive: true,
+      stripTransientCursorShows: true,
+      holdForeground: true
+    })
+    writeTerminalOutput(terminal, '\x1b[?2026l', {
+      foreground: true,
+      latencySensitive: true,
+      stripTransientCursorShows: true,
+      coalesceForeground: true
+    })
+
+    vi.advanceTimersByTime(16)
+    vi.runOnlyPendingTimers()
+
+    expect(terminal.write).toHaveBeenCalledTimes(2)
+    expect(terminal.write.mock.calls.map(([data]) => data)).toEqual([
+      '\x1b[?2026h\x1b[0 q\x1b[?25l\x1b[19;3Hx\x1b[?25h\x1b[?2026l',
+      '\x1b[?2026h\x1b[0 q\x1b[?25l\x1b[19;4Hx\x1b[?25h\x1b[?2026l'
+    ])
+  })
+
   it('keeps transient cursor shows unless the caller opts into stripping', async () => {
     vi.useFakeTimers()
     const { writeTerminalOutput } = await loadScheduler()
diff --git a/src/renderer/src/lib/pane-manager/pane-terminal-output-scheduler.ts b/src/renderer/src/lib/pane-manager/pane-terminal-output-scheduler.ts
index 3778c6dd440..40d6e45e358 100644
--- a/src/renderer/src/lib/pane-manager/pane-terminal-output-scheduler.ts
+++ b/src/renderer/src/lib/pane-manager/pane-terminal-output-scheduler.ts
@@ -71,7 +71,9 @@ const MAX_BACKGROUND_QUEUE_CHUNKS = 4096
 const PARSE_SETTLE_TIMEOUT_MS = 250
 const FOREGROUND_COALESCE_DELAY_MS = 1000
 const FOREGROUND_HOLD_SAFETY_DELAY_MS = 250
-const LATENCY_SENSITIVE_FOREGROUND_COALESCE_DELAY_MS = 32
+// Why: key repeat can tick every 30-50ms; one frame catches split restores
+// without batching multiple typed-character redraws behind the fallback.
+const LATENCY_SENSITIVE_FOREGROUND_COALESCE_DELAY_MS = 16
 const LATENCY_SENSITIVE_FOREGROUND_HOLD_SAFETY_DELAY_MS = 32
 const CURSOR_SHOW_SEQUENCE = '\x1b[?25h'
 const CURSOR_HIDE_SEQUENCE = '\x1b[?25l'