Refactor ReconnectingWebSocket with state machine and fix config change reconnection (#744)

Introduce a formal state machine pattern for WebSocket connection management:
- Add ConnectionState enum (IDLE, CONNECTING, CONNECTED, AWAITING_RETRY,
DISCONNECTED, DISPOSED) to explicitly model the connection lifecycle
- Implement pure reducer function (reduceState) with action-based transitions
- Replace ad-hoc boolean flags (#isDisconnected, #isDisposed, #isConnecting,
#pendingReconnect) with single #state property                                                                     

Fix excessive reconnection on configuration changes:
- Previously, config changes triggered reconnect() on all active sockets
- Now only sockets in DISCONNECTED state are reconnected, since connected
sockets will pick up settings naturally on their next reconnection cycle
- Prevents unnecessary connection churn when users modify settings

Closes #754

Author: EhabY

CHANGELOG.md

@@ -2,6 +2,11 @@
 
 ## Unreleased
 
+### Changed
+
+- WebSocket connections are now more robust and reconnect less frequently, only when truly
+  necessary, reducing unnecessary disconnections and improving stability.
+
 ## [v1.12.1](https://github.com/coder/vscode-coder/releases/tag/v1.12.1) 2026-01-23
 
 ### Fixed

src/api/coderApi.ts

@@ -46,6 +46,7 @@ import {
 	type OneWayWebSocketInit,
 } from "../websocket/oneWayWebSocket";
 import {
+	ConnectionState,
 	ReconnectingWebSocket,
 	type SocketFactory,
 } from "../websocket/reconnectingWebSocket";
@@ -164,19 +165,24 @@ export class CoderApi extends Api implements vscode.Disposable {
 
 	/**
 	 * Watch for configuration changes that affect WebSocket connections.
-	 * When any watched setting changes, all active WebSockets are reconnected.
+	 * Only reconnects DISCONNECTED sockets since they require an explicit reconnect() call.
+	 * Other states will pick up settings naturally.
 	 */
 	private watchConfigChanges(): vscode.Disposable {
 		const settings = webSocketConfigSettings.map((setting) => ({
 			setting,
 			getValue: () => vscode.workspace.getConfiguration().get(setting),
 		}));
 		return watchConfigurationChanges(settings, () => {
-			if (this.reconnectingSockets.size > 0) {
-				this.output.info(
-					`Configuration changed, reconnecting ${this.reconnectingSockets.size} WebSocket(s)`,
+			const socketsToReconnect = [...this.reconnectingSockets].filter(
+				(socket) => socket.state === ConnectionState.DISCONNECTED,
+			);
+			if (socketsToReconnect.length) {
+				this.output.debug(
+					`Configuration changed, ${socketsToReconnect.length}/${this.reconnectingSockets.size} socket(s) in DISCONNECTED state`,
 				);
-				for (const socket of this.reconnectingSockets) {
+				for (const socket of socketsToReconnect) {
+					this.output.debug(`Reconnecting WebSocket: ${socket.url}`);
 					socket.reconnect();
 				}
 			}

src/inbox.ts

@@ -50,11 +50,6 @@ export class Inbox implements vscode.Disposable {
 			logger.info("Listening to Coder Inbox");
 		});
 
-		socket.addEventListener("error", () => {
-			// Errors are already logged internally
-			inbox.dispose();
-		});
-
 		socket.addEventListener("message", (data) => {
 			if (data.parseError) {
 				logger.error("Failed to parse inbox message", data.parseError);