fix: better shutdown logic (#543)

Make cancellation a no-op for unknown sessions, close each
session query during disposal, and run the same cleanup path on
SIGINT and SIGTERM in CLI mode.

Follow up to #530

src/acp-agent.ts

@@ -968,7 +968,7 @@ export class ClaudeAcpAgent implements Agent {
   async cancel(params: CancelNotification): Promise<void> {
     const session = this.sessions[params.sessionId];
     if (!session) {
-      throw new Error("Session not found");
+      return;
     }
     session.cancelled = true;
     for (const [, pending] of session.pendingMessages) {
@@ -988,6 +988,7 @@ export class ClaudeAcpAgent implements Agent {
     await this.cancel({ sessionId });
     session.settingsManager.dispose();
     session.abortController.abort();
+    session.query.close();
     delete this.sessions[sessionId];
   }
 

src/index.ts

@@ -26,15 +26,20 @@ if (process.argv.includes("--cli")) {
 
   const { connection, agent } = runAcp();
 
-  // Exit cleanly when the ACP connection closes (e.g. stdin EOF, transport
-  // error). Without this, `process.stdin.resume()` keeps the event loop
-  // alive indefinitely, causing orphan process accumulation in oneshot mode.
-  connection.closed.then(async () => {
+  async function shutdown() {
     await agent.dispose().catch((err) => {
       console.error("Error during cleanup:", err);
     });
     process.exit(0);
-  });
+  }
+
+  // Exit cleanly when the ACP connection closes (e.g. stdin EOF, transport
+  // error). Without this, `process.stdin.resume()` keeps the event loop
+  // alive indefinitely, causing orphan process accumulation in oneshot mode.
+  connection.closed.then(shutdown);
+
+  process.on("SIGTERM", shutdown);
+  process.on("SIGINT", shutdown);
 
   // Keep process alive while connection is open
   process.stdin.resume();

src/tests/acp-agent.test.ts

@@ -1538,7 +1538,7 @@ describe("session/close", () => {
 
   function injectSession(agent: ClaudeAcpAgent, sessionId: string) {
     function* empty() {}
-    const gen = Object.assign(empty(), { interrupt: vi.fn() });
+    const gen = Object.assign(empty(), { interrupt: vi.fn(), close: vi.fn() });
     agent.sessions[sessionId] = {
       query: gen as any,
       input: new Pushable(),
@@ -1633,6 +1633,7 @@ describe("getOrCreateSession param change detection", () => {
     function* empty() {}
     const gen = Object.assign(empty(), {
       interrupt: vi.fn(),
+      close: vi.fn(),
       supportedCommands: vi.fn().mockResolvedValue([]),
     });
     agent.sessions[sessionId] = {