From 32665a4af7fe429f58436e010fb4e74b57bcdcc7 Mon Sep 17 00:00:00 2001
From: roboomp <omp@can.ac>
Date: Tue, 14 Jul 2026 19:26:23 +0000
Subject: [PATCH] fix(tui): kept tmux keyboard input in legacy mode

Skipped the xterm modifyOtherKeys fallback inside tmux when Kitty keyboard negotiation is unavailable, preserving legacy key delivery.

Added a regression test for DA1-driven negotiation under tmux.

Fixes #5378
---
 packages/tui/CHANGELOG.md                     |  4 ++++
 packages/tui/src/terminal.ts                  |  1 +
 .../test/kitty-keyboard-da1-ordering.test.ts  | 21 ++++++++++++++++++-
 3 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/packages/tui/CHANGELOG.md b/packages/tui/CHANGELOG.md
index 2a6e16a07..4837ee707 100644
--- a/packages/tui/CHANGELOG.md
+++ b/packages/tui/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- Fixed tmux sessions becoming unresponsive after terminal capability replies by keeping keyboard input in legacy mode when the Kitty protocol is unavailable ([#5378](https://github.com/can1357/oh-my-pi/issues/5378)).
+
 ## [16.5.0] - 2026-07-13
 
 ### Changed
diff --git a/packages/tui/src/terminal.ts b/packages/tui/src/terminal.ts
index b35dfa1f5..eb33c98e2 100644
--- a/packages/tui/src/terminal.ts
+++ b/packages/tui/src/terminal.ts
@@ -36,6 +36,7 @@ export function resolveHangulCompatibilityJamoWidthFromTerminalIdentity(
 }
 
 function shouldEnableModifyOtherKeysFallback(env: NodeJS.ProcessEnv = Bun.env): boolean {
+	if (isInsideTmux(env)) return false;
 	if (!env.SSH_CONNECTION && !env.SSH_TTY && !env.SSH_CLIENT) return true;
 	return TERMINAL.id !== "base" && TERMINAL.id !== "trueColor";
 }
diff --git a/packages/tui/test/kitty-keyboard-da1-ordering.test.ts b/packages/tui/test/kitty-keyboard-da1-ordering.test.ts
index f38a158c5..300e16d1c 100644
--- a/packages/tui/test/kitty-keyboard-da1-ordering.test.ts
+++ b/packages/tui/test/kitty-keyboard-da1-ordering.test.ts
@@ -22,9 +22,10 @@ class ModalProbe implements Component {
 const originalSshConnection = Bun.env.SSH_CONNECTION;
 const originalSshTty = Bun.env.SSH_TTY;
 const originalSshClient = Bun.env.SSH_CLIENT;
+const originalTmux = Bun.env.TMUX;
 const originalTerminalId = TERMINAL.id;
 
-function restoreEnv(name: "SSH_CONNECTION" | "SSH_TTY" | "SSH_CLIENT", value: string | undefined): void {
+function restoreEnv(name: "SSH_CONNECTION" | "SSH_TTY" | "SSH_CLIENT" | "TMUX", value: string | undefined): void {
 	if (value === undefined) {
 		delete Bun.env[name];
 		return;
@@ -41,6 +42,7 @@ describe("ProcessTerminal kitty keyboard progressive-enhancement ordering", () =
 		restoreEnv("SSH_CONNECTION", originalSshConnection);
 		restoreEnv("SSH_TTY", originalSshTty);
 		restoreEnv("SSH_CLIENT", originalSshClient);
+		restoreEnv("TMUX", originalTmux);
 		Object.defineProperty(TERMINAL, "id", { value: originalTerminalId, configurable: true });
 	});
 
@@ -110,6 +112,23 @@ describe("ProcessTerminal kitty keyboard progressive-enhancement ordering", () =
 		expect(harness.terminal.keyboardEnhancementEnterSequence).toBeNull();
 	});
 
+	it("keeps legacy keyboard input under tmux when kitty is unavailable", async () => {
+		Bun.env.TMUX = "/tmp/tmux-501/default,1234,0";
+		delete Bun.env.SSH_CONNECTION;
+		delete Bun.env.SSH_TTY;
+		delete Bun.env.SSH_CLIENT;
+		harness = createProcessTerminalRenderHarness(100, 30);
+		await harness.settle();
+		harness.writes.length = 0;
+
+		await harness.feed("\x1b[?1;2c");
+
+		const out = harness.writes.join("");
+		expect(harness.terminal.kittyProtocolActive).toBe(false);
+		expect(out).not.toContain("\x1b[>4;2m");
+		expect(harness.terminal.keyboardEnhancementEnterSequence).toBeNull();
+	});
+
 	it("reasserts modifyOtherKeys fallback when fullscreen overlays enter the alternate screen", async () => {
 		harness = createProcessTerminalRenderHarness(100, 30);
 		await harness.settle();