From 9b739fd8e4d0f61ed2675f51f10398b7c534c648 Mon Sep 17 00:00:00 2001
From: Chris Wanstrath <chris@ozmm.org>
Date: Thu, 12 Mar 2026 14:47:13 -0700
Subject: [PATCH] Simplify killTree with single ps call

---
 src/run.ts | 41 +++++++++++++++++++----------------------
 1 file changed, 19 insertions(+), 22 deletions(-)

diff --git a/src/run.ts b/src/run.ts
index d0f9beb..b5fbcc6 100644
--- a/src/run.ts
+++ b/src/run.ts
@@ -28,30 +28,27 @@ type RunOptions = {
   onCommand?: (cmd: Command) => void
 }
 
-function getDescendants(pid: number): number[] {
-  try {
-    const result = Bun.spawnSync(["ps", "-o", "pid=", "--ppid", String(pid)])
-    const output = new TextDecoder().decode(result.stdout)
-    const children = output.trim().split("\n").filter(Boolean).map(s => parseInt(s.trim(), 10)).filter(n => !isNaN(n))
-    const all: number[] = []
-    for (const child of children) {
-      all.push(...getDescendants(child))
-      all.push(child)
-    }
-    return all
-  } catch {
-    return []
-  }
-}
-
 function killTree(pid: number): void {
-  const descendants = getDescendants(pid)
-  // Kill process group first
+  // Find any processes that escaped the process group (e.g. via setsid)
+  // using a single cross-platform ps call, then kill them before the group.
+  try {
+    const result = Bun.spawnSync(["ps", "-eo", "pid,pgid"])
+    const output = result.stdout.toString()
+    const pgid = String(pid)
+    const escapees: number[] = []
+    for (const line of output.split("\n")) {
+      const parts = line.trim().split(/\s+/)
+      if (parts[1] === pgid) {
+        const p = parseInt(parts[0]!, 10)
+        if (!isNaN(p) && p !== pid) escapees.push(p)
+      }
+    }
+    for (const p of escapees) {
+      try { process.kill(p, "SIGKILL") } catch {}
+    }
+  } catch {}
+  // Kill the process group
   try { process.kill(-pid, "SIGKILL") } catch {}
-  // Then kill any descendants that escaped the process group
-  for (const d of descendants) {
-    try { process.kill(d, "SIGKILL") } catch {}
-  }
 }
 
 const SENTINEL_PREFIX = "__SHOUT_SENTINEL_"