Cherry-pick process lifecycle fixes for multi-day autonomous operation

- shell: add trackDetachedChildPid / untrackDetachedChildPid /
  killTrackedDetachedChildren (#9b7948c)
- bash: track/untrack detached child PIDs so they are killed on shutdown
- interactive-mode: register SIGTERM/SIGHUP handlers for clean shutdown
  (#5d440b0); kill tracked bash children on shutdown
- rpc-mode: register SIGTERM/SIGHUP handlers, refactor to forceShutdown()
  that deduplicates shutdown path (#5d440b0); kill tracked bash children
- print-mode: register SIGTERM/SIGHUP handlers for graceful exit

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/pi-coding-agent/src/core/tools/bash.ts

@@ -6,7 +6,7 @@ import { join } from "node:path";
 import type { AgentTool } from "@singularity-forge/pi-agent-core";
 import { type Static, Type } from "@sinclair/typebox";
 import { spawn } from "child_process";
-import { getShellConfig, getShellEnv, killProcessTree, sanitizeCommand } from "../../utils/shell.js";
+import { getShellConfig, getShellEnv, killProcessTree, sanitizeCommand, trackDetachedChildPid, untrackDetachedChildPid } from "../../utils/shell.js";
 import { type BashInterceptorRule, compileInterceptor, DEFAULT_BASH_INTERCEPTOR_RULES } from "./bash-interceptor.js";
 import { DEFAULT_MAX_BYTES, DEFAULT_MAX_LINES, formatSize, type TruncationResult, truncateTail } from "./truncate.js";
 import type { ArtifactManager } from "../artifact-manager.js";
@@ -168,6 +168,7 @@ const defaultBashOperations: BashOperations = {
 				env: env ?? getShellEnv(),
 				stdio: ["ignore", "pipe", "pipe"],
 			});
+			if (child.pid) trackDetachedChildPid(child.pid);
 
 			let timedOut = false;
 
@@ -192,6 +193,7 @@ const defaultBashOperations: BashOperations = {
 
 			// Handle shell spawn errors
 			child.on("error", (err) => {
+				if (child.pid) untrackDetachedChildPid(child.pid);
 				if (timeoutHandle) clearTimeout(timeoutHandle);
 				if (signal) signal.removeEventListener("abort", onAbort);
 				reject(err);
@@ -214,6 +216,7 @@ const defaultBashOperations: BashOperations = {
 
 			// Handle process exit
 			child.on("close", (code) => {
+				if (child.pid) untrackDetachedChildPid(child.pid);
 				restoreWindowsVTInput();
 				if (timeoutHandle) clearTimeout(timeoutHandle);
 				if (signal) signal.removeEventListener("abort", onAbort);

packages/pi-coding-agent/src/modes/interactive/interactive-mode.ts

@@ -102,6 +102,7 @@ import {
 	handleModelCommand as handleModelCommandController,
 	updateAvailableProviderCount as updateAvailableProviderCountController,
 } from "./controllers/model-controller.js";
+import { killTrackedDetachedChildren } from "../../utils/shell.js";
 import {
 	getAvailableThemes,
 	getAvailableThemesWithPaths,
@@ -211,6 +212,8 @@ export class InteractiveMode {
 	// Agent subscription unsubscribe function
 	private unsubscribe?: () => void;
 
+	private signalCleanupHandlers: Array<() => void> = [];
+
 	// Branch change listener unsubscribe function
 	private _branchChangeUnsub?: () => void;
 
@@ -412,6 +415,8 @@ export class InteractiveMode {
 	async init(): Promise<void> {
 		if (this.isInitialized) return;
 
+		this.registerSignalHandlers();
+
 		// Load changelog (only show new entries, skip for resumed sessions)
 		this.changelogMarkdown = this.getChangelogForDisplay();
 
@@ -2388,6 +2393,22 @@ export class InteractiveMode {
 	 */
 	private isShuttingDown = false;
 
+	private registerSignalHandlers(): void {
+		this.unregisterSignalHandlers();
+		const signals: NodeJS.Signals[] = ["SIGTERM"];
+		if (process.platform !== "win32") signals.push("SIGHUP");
+		for (const signal of signals) {
+			const handler = () => { void this.shutdown(); };
+			process.on(signal, handler);
+			this.signalCleanupHandlers.push(() => process.off(signal, handler));
+		}
+	}
+
+	private unregisterSignalHandlers(): void {
+		for (const cleanup of this.signalCleanupHandlers) cleanup();
+		this.signalCleanupHandlers = [];
+	}
+
 	private async shutdown(): Promise<void> {
 		const shutdownBehavior = this.options.shutdownBehavior ?? "exit_process";
 		if (shutdownBehavior === "ignore") {
@@ -2397,6 +2418,8 @@ export class InteractiveMode {
 
 		if (this.isShuttingDown) return;
 		this.isShuttingDown = true;
+		this.unregisterSignalHandlers();
+		killTrackedDetachedChildren();
 
 		// Flush any queued settings writes before shutdown
 		await this.settingsManager.flush();
@@ -3988,6 +4011,7 @@ export class InteractiveMode {
 	}
 
 	stop(): void {
+		this.unregisterSignalHandlers();
 		if (this.loadingAnimation) {
 			this.loadingAnimation.stop();
 			this.loadingAnimation = undefined;

packages/pi-coding-agent/src/modes/print-mode.ts

@@ -53,6 +53,29 @@ export async function runPrintMode(session: AgentSession, options: PrintModeOpti
 	});
 
 	let exitCode = 0;
+	let disposed = false;
+	const signalCleanupHandlers: Array<() => void> = [];
+
+	const disposeSession = (): void => {
+		if (disposed) return;
+		disposed = true;
+		unsubscribe();
+	};
+
+	const registerSignalHandlers = (): void => {
+		const signals: NodeJS.Signals[] = ["SIGTERM"];
+		if (process.platform !== "win32") signals.push("SIGHUP");
+		for (const signal of signals) {
+			const handler = () => {
+				disposeSession();
+				process.exit(signal === "SIGHUP" ? 129 : 143);
+			};
+			process.on(signal, handler);
+			signalCleanupHandlers.push(() => process.off(signal, handler));
+		}
+	};
+
+	registerSignalHandlers();
 
 	try {
 		// Send initial message with attachments
@@ -97,7 +120,8 @@ export async function runPrintMode(session: AgentSession, options: PrintModeOpti
 			});
 		});
 	} finally {
-		unsubscribe();
+		for (const cleanup of signalCleanupHandlers) cleanup();
+		disposeSession();
 	}
 
 	if (exitCode !== 0) {

packages/pi-coding-agent/src/modes/rpc/rpc-mode.ts

@@ -13,6 +13,7 @@
 
 import * as crypto from "node:crypto";
 import type { AgentSession } from "../../core/agent-session.js";
+import { killTrackedDetachedChildren } from "../../utils/shell.js";
 import type {
 	ExtensionUIContext,
 	ExtensionUIDialogOptions,
@@ -84,6 +85,8 @@ export async function runRpcMode(session: AgentSession): Promise<never> {
 
 	// Shutdown request flag
 	let shutdownRequested = false;
+	let shuttingDown = false;
+	const signalCleanupHandlers: Array<() => void> = [];
 
 	// v2 protocol version detection state
 	let protocolVersion: 1 | 2 = 1;
@@ -822,19 +825,35 @@ export async function runRpcMode(session: AgentSession): Promise<never> {
 	 */
 	let detachInput = () => {};
 
-	async function checkShutdownRequested(): Promise<void> {
-		if (!shutdownRequested) return;
-
+	async function forceShutdown(exitCode = 0): Promise<never> {
+		if (shuttingDown) process.exit(exitCode);
+		shuttingDown = true;
+		killTrackedDetachedChildren();
+		for (const cleanup of signalCleanupHandlers) cleanup();
 		const currentRunner = session.extensionRunner;
 		if (currentRunner?.hasHandlers("session_shutdown")) {
 			await currentRunner.emit({ type: "session_shutdown" });
 		}
-
 		unsubscribe();
 		embeddedInteractiveMode?.stop();
 		detachInput();
 		process.stdin.pause();
-		process.exit(0);
+		process.exit(exitCode);
+	}
+
+	const registerSignalHandlers = (): void => {
+		const signals: NodeJS.Signals[] = ["SIGTERM"];
+		if (process.platform !== "win32") signals.push("SIGHUP");
+		for (const signal of signals) {
+			const handler = () => { void forceShutdown(signal === "SIGHUP" ? 129 : 143); };
+			process.on(signal, handler);
+			signalCleanupHandlers.push(() => process.off(signal, handler));
+		}
+	};
+
+	async function checkShutdownRequested(): Promise<void> {
+		if (!shutdownRequested) return;
+		await forceShutdown(0);
 	}
 
 	const handleInputLine = async (line: string) => {
@@ -889,6 +908,8 @@ export async function runRpcMode(session: AgentSession): Promise<never> {
 		}
 	};
 
+	registerSignalHandlers();
+
 	detachInput = attachJsonlLineReader(process.stdin, (line) => {
 		void handleInputLine(line);
 	});

packages/pi-coding-agent/src/utils/shell.ts

@@ -183,6 +183,23 @@ export function sanitizeBinaryOutput(str: string): string {
 		.join("");
 }
 
+const trackedDetachedChildPids = new Set<number>();
+
+export function trackDetachedChildPid(pid: number): void {
+	trackedDetachedChildPids.add(pid);
+}
+
+export function untrackDetachedChildPid(pid: number): void {
+	trackedDetachedChildPids.delete(pid);
+}
+
+export function killTrackedDetachedChildren(): void {
+	for (const pid of trackedDetachedChildPids) {
+		killProcessTree(pid);
+	}
+	trackedDetachedChildPids.clear();
+}
+
 /**
  * Kill a process and all its children (cross-platform)
  */