From e5a4d5c0749a8e43a082b5fd251cfa76ae11c3cf Mon Sep 17 00:00:00 2001
From: Brennan Benson <79079362+brennanb2025@users.noreply.github.com>
Date: Tue, 14 Jul 2026 02:21:15 -0700
Subject: [PATCH] fix(terminal): skip output for certified-dead renderers

---
 .../pane-manager/pane-terminal-output-scheduler.test.ts    | 3 +++
 .../src/lib/pane-manager/pane-terminal-output-scheduler.ts | 7 +++++++
 2 files changed, 10 insertions(+)

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 d14defde9d9..92a5a2b5828 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
@@ -1534,6 +1534,9 @@ describe('pane terminal output scheduler', () => {
       expect(hasTerminalParseProgressSince(terminal, generation)).toBe(false)
       expect(recoveryReasons).toEqual(['write-stalled'])
       expect(isTerminalWritePipelineCertifiedDead(terminal)).toBe(true)
+      // Only the first rejection touches xterm; later PTY deliveries credit
+      // directly while recovery owns the certified-dead instance.
+      expect(terminal.write).toHaveBeenCalledTimes(1)
       expect(onParsed).not.toHaveBeenCalled()
       for (const ackCredit of ackCredits) {
         expect(ackCredit).toHaveBeenCalledTimes(1)
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 4e1e08284cd..a641f0b0f81 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
@@ -21,6 +21,7 @@ import {
   armTerminalWriteStallWatch,
   cancelTerminalWriteStallWatch,
   failTerminalWriteStallWatch,
+  isTerminalWritePipelineCertifiedDead,
   settleTerminalWriteStallWatch
 } from './terminal-write-pipeline-health'
 import {
@@ -1123,6 +1124,12 @@ export function writeTerminalOutput(
   options: WriteTerminalOutputOptions
 ): void {
   exposeDebugApi()
+  // Why: recovery may be budget-delayed while PTY output keeps flowing. Main
+  // owns the authoritative buffer; credit delivery without waking dead xterm.
+  if (isTerminalWritePipelineCertifiedDead(terminal)) {
+    options.ackCredit?.()
+    return
+  }
   if (!data) {
     // Why: an empty write still consumed its delivery — credit or main's
     // in-flight window leaks.