Add killTree to recursively kill child processes

src/run.ts

@@ -28,6 +28,32 @@ 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
+  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_"
 
 function buildScript(commands: Command[], sentinel: string): string {
@@ -190,7 +216,7 @@ export async function runFile(
     }
   } finally {
     if (proc.pid) {
-      try { process.kill(-proc.pid, "SIGKILL") } catch {}
+      killTree(proc.pid)
     }
   }
 }