[miniflare] Fix resource leaks during config updates

- Only close/recreate devRegistryDispatcher when the port changes,
  matching the existing runtimeDispatcher pattern (fixes #13584)
- Dispose old InspectorProxy instances before replacing them in
  updateConnection, preventing leaked WebSockets and keepalive
  timers (fixes #13585)

Author: petebacondarwin

.changeset/miniflare-dispose-cleanup-followup.md

@@ -0,0 +1,10 @@
+---
+"miniflare": patch
+---
+
+Fix resource leaks during config updates
+
+Two follow-up fixes to the dispose cleanup in #13515:
+
+- Only close and recreate the dev-registry dispatcher when its port actually changes, matching the existing `runtimeDispatcher` behavior. Previously, every config update unconditionally tore down and rebuilt the connection pool, which could cause brief request failures if a registry push was in-flight.
+- Dispose old `InspectorProxy` instances before replacing them during `updateConnection()`. Previously, stale proxies were silently discarded, leaking their runtime WebSocket connections and 10-second keepalive interval timers.

packages/miniflare/src/index.ts

@@ -1107,6 +1107,7 @@ export class Miniflare {
 	 * Called when the dev registry detects changes to external services.
 	 */
 	#devRegistryDispatcher?: Dispatcher;
+	#devRegistryPort?: number;
 
 	async #pushRegistryUpdate(retries = 3): Promise<void> {
 		if (this.#disposeController.signal.aborted) return;
@@ -2422,14 +2423,19 @@ export class Miniflare {
 
 		// Set up a direct dispatcher to the dev-registry-proxy socket so we can
 		// push registry updates without routing through the entry worker.
+		// Only close/recreate when the port actually changes, to avoid tearing
+		// down the connection pool while a #pushRegistryUpdate is in-flight.
 		const devRegistryPort = maybeSocketPorts.get(SOCKET_DEV_REGISTRY);
-		void this.#devRegistryDispatcher?.close().catch(() => {});
-		if (devRegistryPort !== undefined) {
-			this.#devRegistryDispatcher = new Pool(
-				new URL(`http://127.0.0.1:${devRegistryPort}`)
-			);
-		} else {
-			this.#devRegistryDispatcher = undefined;
+		if (devRegistryPort !== this.#devRegistryPort) {
+			void this.#devRegistryDispatcher?.close().catch(() => {});
+			this.#devRegistryPort = devRegistryPort;
+			if (devRegistryPort !== undefined) {
+				this.#devRegistryDispatcher = new Pool(
+					new URL(`http://127.0.0.1:${devRegistryPort}`)
+				);
+			} else {
+				this.#devRegistryDispatcher = undefined;
+			}
 		}
 		if (this.#proxyClient === undefined) {
 			this.#proxyClient = new ProxyClient(

packages/miniflare/src/plugins/core/inspector-proxy/inspector-proxy-controller.ts

@@ -289,6 +289,10 @@ export class InspectorProxyController {
 			id: string;
 		}[];
 
+		// Dispose old proxies before replacing them, so their runtime WebSocket
+		// connections and keepalive intervals are properly cleaned up.
+		await Promise.all(this.#proxies.map((proxy) => proxy.dispose()));
+
 		this.#proxies = workerdInspectorJson
 			.map(({ id }) => {
 				if (!id.startsWith("core:user:")) {