Don't terminate extension host on a timeout

We will clean it up on our end if necessary. This allows reconnections
after any length of time.

src/connection.ts

@@ -17,10 +17,7 @@ export abstract class Connection {
 	private disposed = false;
 	private _offline: number | undefined;
 
-	public constructor(protected protocol: Protocol) {
-		protocol.onClose(() => this.dispose()); // Explicit close.
-		protocol.onSocketClose(() => this._offline = Date.now()); // Might reconnect.
-	}
+	public constructor(protected protocol: Protocol, public readonly token: string) {}
 
 	public get offline(): number | undefined {
 		return this._offline;
@@ -39,6 +36,12 @@ export abstract class Connection {
 		}
 	}
 
+	protected setOffline(): void {
+		if (!this._offline) {
+			this._offline = Date.now();
+		}
+	}
+
 	/**
 	 * Set up the connection on a new socket.
 	 */
@@ -50,6 +53,12 @@ export abstract class Connection {
  * Used for all the IPC channels.
  */
 export class ManagementConnection extends Connection {
+	public constructor(protected protocol: Protocol, token: string) {
+		super(protocol, token);
+		protocol.onClose(() => this.dispose()); // Explicit close.
+		protocol.onSocketClose(() => this.setOffline()); // Might reconnect.
+	}
+
 	protected doDispose(): void {
 		this.protocol.sendDisconnect();
 		this.protocol.dispose();
@@ -66,11 +75,11 @@ export class ExtensionHostConnection extends Connection {
 	private process?: cp.ChildProcess;
 
 	public constructor(
-		locale:string, protocol: Protocol, buffer: VSBuffer,
+		locale:string, protocol: Protocol, buffer: VSBuffer, token: string,
 		private readonly log: ILogService,
 		private readonly environment: IEnvironmentService,
 	) {
-		super(protocol);
+		super(protocol, token);
 		this.protocol.dispose();
 		this.spawn(locale, buffer).then((p) => this.process = p);
 		this.protocol.getUnderlyingSocket().pause();
@@ -129,6 +138,9 @@ export class ExtensionHostConnection extends Connection {
 				const severity = (<any>this.log)[event.severity] ? event.severity : "info";
 				(<any>this.log)[severity]("Extension host", event.arguments);
 			}
+			if (event && event.type === "VSCODE_EXTHOST_DISCONNECTED") {
+				this.setOffline();
+			}
 		});
 
 		const listen = (message: IExtHostReadyMessage) => {

src/server.ts

@@ -449,7 +449,7 @@ export class MainServer extends Server {
 	public readonly onDidClientConnect = this._onDidClientConnect.event;
 	private readonly ipc = new IPCServer(this.onDidClientConnect);
 
-	private readonly maxOfflineConnections = 5;
+	private readonly maxExtraOfflineConnections = 0;
 	private readonly connections = new Map<ConnectionType, Map<string, Connection>>();
 
 	private readonly services = new ServiceCollection();
@@ -601,7 +601,7 @@ export class MainServer extends Server {
 
 				let connection: Connection;
 				if (message.desiredConnectionType === ConnectionType.Management) {
-					connection = new ManagementConnection(protocol);
+					connection = new ManagementConnection(protocol, token);
 					this._onDidClientConnect.fire({
 						protocol, onDidClientDisconnect: connection.onClose,
 					});
@@ -609,28 +609,26 @@ export class MainServer extends Server {
 					const buffer = protocol.readEntireBuffer();
 					connection = new ExtensionHostConnection(
 						message.args ? message.args.language : "en",
-						protocol, buffer,
+						protocol, buffer, token,
 						this.services.get(ILogService) as ILogService,
 						this.services.get(IEnvironmentService) as IEnvironmentService,
 					);
 				}
 				connections.set(token, connection);
-				this.disposeOldOfflineConnections();
 				connection.onClose(() => connections.delete(token));
+				this.disposeOldOfflineConnections(connections);
 				break;
 			case ConnectionType.Tunnel: return protocol.tunnel();
 			default: throw new Error("Unrecognized connection type");
 		}
 	}
 
-	private disposeOldOfflineConnections(): void {
-		this.connections.forEach((connections) => {
-			const offline = Array.from(connections.values())
-				.filter((connection) => typeof connection.offline !== "undefined");
-			for (let i = 0, max = offline.length - this.maxOfflineConnections; i < max; ++i) {
-				offline[i].dispose();
-			}
-		});
+	private disposeOldOfflineConnections(connections: Map<string, Connection>): void {
+		const offline = Array.from(connections.values())
+			.filter((connection) => typeof connection.offline !== "undefined");
+		for (let i = 0, max = offline.length - this.maxExtraOfflineConnections; i < max; ++i) {
+			offline[i].dispose();
+		}
 	}
 
 	private async initializeServices(args: ParsedArgs): Promise<void> {