Merge pull request #22 from jeffklassen/fix/email-idle-loop-resource-leak

fix: await IDLE loop in email channel disconnect to prevent resource leak

Author: mcheemaa

src/channels/__tests__/email.test.ts

@@ -5,7 +5,18 @@ import { EmailChannel, type EmailChannelConfig } from "../email.ts";
 const mockConnect = mock(() => Promise.resolve());
 const mockLogout = mock(() => Promise.resolve());
 const mockGetMailboxLock = mock(() => Promise.resolve({ release: () => {} }));
-const mockIdle = mock(() => new Promise(() => {}));
+const mockIdle = mock(
+	(opts?: { abort?: AbortSignal }) =>
+		new Promise<void>((_resolve, reject) => {
+			if (opts?.abort) {
+				if (opts.abort.aborted) {
+					reject(new Error("abort"));
+					return;
+				}
+				opts.abort.addEventListener("abort", () => reject(new Error("abort")), { once: true });
+			}
+		}),
+);
 const mockFetch = mock(function* () {
 	// Empty generator - no unread messages
 });
@@ -141,6 +152,34 @@ describe("EmailChannel", () => {
 		expect(callArgs.text).toBe("Plain text content");
 	});
 
+	test("disconnect awaits IDLE loop before logout", async () => {
+		const channel = new EmailChannel(testConfig);
+		await channel.connect();
+
+		// disconnect should complete without hanging — the IDLE loop
+		// must terminate before logout is called
+		await channel.disconnect();
+
+		// Verify logout was called (meaning IDLE loop finished first)
+		expect(mockLogout).toHaveBeenCalledTimes(1);
+		expect(channel.isConnected()).toBe(false);
+	});
+
+	test("rapid disconnect and reconnect does not leak IDLE loops", async () => {
+		const channel = new EmailChannel(testConfig);
+		await channel.connect();
+
+		await channel.disconnect();
+		mockGetMailboxLock.mockClear();
+
+		// Reconnect should work cleanly without competing for the lock
+		await channel.connect();
+		expect(channel.isConnected()).toBe(true);
+		expect(mockGetMailboxLock).toHaveBeenCalledTimes(1);
+
+		await channel.disconnect();
+	});
+
 	test("send generates unique message ID", async () => {
 		const channel = new EmailChannel(testConfig);
 		await channel.connect();

src/channels/email.ts

@@ -51,6 +51,7 @@ export class EmailChannel implements Channel {
 	private transporter: NodemailerTransport | null = null;
 	private threads = new Map<string, EmailThread>();
 	private idleAbort: AbortController | null = null;
+	private idleLoopPromise: Promise<void> | null = null;
 
 	constructor(config: EmailChannelConfig) {
 		this.config = config;
@@ -86,8 +87,8 @@ export class EmailChannel implements Channel {
 			this.connectionState = "connected";
 			console.log("[email] SMTP configured");
 
-			// Start IDLE listening
-			void this.startIdleLoop();
+			// Start IDLE listening (tracked so disconnect can await it)
+			this.idleLoopPromise = this.startIdleLoop();
 		} catch (err: unknown) {
 			this.connectionState = "error";
 			const msg = err instanceof Error ? err.message : String(err);
@@ -99,16 +100,23 @@ export class EmailChannel implements Channel {
 	async disconnect(): Promise<void> {
 		if (this.connectionState === "disconnected") return;
 
+		this.connectionState = "disconnected";
 		this.idleAbort?.abort();
 
+		// Wait for the IDLE loop to finish and release the mailbox lock
+		// before logging out, so a subsequent connect() won't race.
+		if (this.idleLoopPromise) {
+			await this.idleLoopPromise;
+			this.idleLoopPromise = null;
+		}
+
 		try {
 			await this.imapClient?.logout();
 		} catch (err: unknown) {
 			const msg = err instanceof Error ? err.message : String(err);
 			console.warn(`[email] Error during IMAP disconnect: ${msg}`);
 		}
 
-		this.connectionState = "disconnected";
 		console.log("[email] Disconnected");
 	}