[vite-plugin-cloudflare] make sure that runner initialization is properly validated (#7846)

Author: dario-piotrowicz

.changeset/smart-mice-appear.md

@@ -0,0 +1,5 @@
+---
+"@cloudflare/vite-plugin": patch
+---
+
+fix: make sure that runner initialization is properly validated

packages/vite-plugin-cloudflare/src/cloudflare-environment.ts

@@ -99,7 +99,10 @@ export class CloudflareDevEnvironment extends vite.DevEnvironment {
 			}
 		);
 
-		assert(response.ok, "Failed to initialize module runner");
+		assert(
+			response.ok,
+			`Failed to initialize module runner, error: ${await response.text()}`
+		);
 
 		const webSocket = response.webSocket;
 		assert(webSocket, "Failed to establish WebSocket");

packages/vite-plugin-cloudflare/src/runner-worker/index.ts

@@ -173,7 +173,14 @@ export function createWorkerEntrypointWrapper(
 
 				if (url.pathname === INIT_PATH) {
 					const { 0: client, 1: server } = new WebSocketPair();
-					createModuleRunner(this.env, server);
+					try {
+						await createModuleRunner(this.env, server);
+					} catch (e) {
+						return new Response(
+							e instanceof Error ? e.message : JSON.stringify(e),
+							{ status: 500 }
+						);
+					}
 
 					return new Response(null, { status: 101, webSocket: client });
 				}