From ffff9109c34a1e9575104e879320b24028b816d0 Mon Sep 17 00:00:00 2001
From: Lawrence Chen <54008264+lawrencecchen@users.noreply.github.com>
Date: Tue, 1 Sep 2026 05:14:07 -0700
Subject: [PATCH 1/2] cmux-tui: reap child when reaper thread spawn fails

---
 cmux-tui/crates/cmux-tui-core/src/surface.rs | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/cmux-tui/crates/cmux-tui-core/src/surface.rs b/cmux-tui/crates/cmux-tui-core/src/surface.rs
index 1ac55ea399a1..eb999cb8d0ff 100644
--- a/cmux-tui/crates/cmux-tui-core/src/surface.rs
+++ b/cmux-tui/crates/cmux-tui-core/src/surface.rs
@@ -2563,9 +2563,13 @@ impl Surface {
 
         // Child reaper: retain the native status and rendezvous with PTY EOF
         // so final output is visible before the mux observes completion.
-        std::thread::Builder::new().name(format!("surface-{id}-wait")).spawn({
+        let child_slot = Arc::new(Mutex::new(Some(child)));
+        let child_for_reaper = child_slot.clone();
+        let reaper = std::thread::Builder::new().name(format!("surface-{id}-wait")).spawn({
             let surface = surface.clone();
             move || {
+                let mut child =
+                    child_for_reaper.lock().unwrap().take().expect("child reaper owns child");
                 let exit = wait_for_native_child_status(child.as_mut());
                 if let Some(pty) = surface.as_pty() {
                     *pty.exit.lock().unwrap() = Some(exit);
@@ -2573,7 +2577,14 @@ impl Surface {
                 close_local_terminal_master_after_exit(&surface);
                 publish_local_exit_if_ready(&surface);
             }
-        })?;
+        });
+        if let Err(error) = reaper {
+            if let Some(mut child) = child_slot.lock().unwrap().take() {
+                let _ = child.kill();
+                let _ = child.wait();
+            }
+            return Err(error.into());
+        }
 
         Ok(surface)
     }

From 4b9c086e4c9e869b46eb9cf9454a85149110ca25 Mon Sep 17 00:00:00 2001
From: Lawrence Chen <54008264+lawrencecchen@users.noreply.github.com>
Date: Tue, 1 Sep 2026 05:55:11 -0700
Subject: [PATCH 2/2] cmux-tui: close PTY master on reaper spawn failure

---
 cmux-tui/crates/cmux-tui-core/src/surface.rs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/cmux-tui/crates/cmux-tui-core/src/surface.rs b/cmux-tui/crates/cmux-tui-core/src/surface.rs
index eb999cb8d0ff..dac1b8cc87e3 100644
--- a/cmux-tui/crates/cmux-tui-core/src/surface.rs
+++ b/cmux-tui/crates/cmux-tui-core/src/surface.rs
@@ -2583,6 +2583,7 @@ impl Surface {
                 let _ = child.kill();
                 let _ = child.wait();
             }
+            close_local_terminal_master_after_exit(&surface);
             return Err(error.into());
         }