fix(deno): Don't throw in Deno.serve wrapper when no client is bound

packages/deno/src/wrap-deno-request-handler.ts

@@ -11,6 +11,7 @@ import {
   captureBodyFromWinterCGRequest,
   captureException,
   continueTrace,
+  debug,
   getClient,
   getHttpSpanDetailsFromUrlObject,
   hasSpanStreamingEnabled,
@@ -48,7 +49,12 @@ export const wrapDenoRequestHandler = <Addr extends Deno.Addr = Deno.Addr>(
 
     const client = getClient();
     if (!client) {
-      throw new Error('could not get Deno client. Did you run Sentry.init?');
+      // `denoServeIntegration` patches `Deno.serve` from `Client.init()`, which a
+      // directly-constructed client also runs — that path never calls
+      // `setCurrentClient`, so the patch can be live with no client bound. Keep
+      // requests flowing to the user's handler, uninstrumented.
+      debug.warn('Cannot instrument Deno.serve request. No client defined.');
+      return handler();
     }
     isolationScope.setClient(client);
 

packages/deno/test/deno-serve-no-client.test.ts

@@ -0,0 +1,67 @@
+// <reference lib="deno.ns" />
+
+/**
+ * Lives in its own file because it wipes the global carrier; Deno gives each test
+ * file a fresh module graph, so the wipe stays contained here.
+ */
+
+import { getMainCarrier } from '@sentry/core';
+import { assertEquals } from 'https://deno.land/std@0.212.0/assert/assert_equals.ts';
+import { assertNotEquals } from 'https://deno.land/std@0.212.0/assert/assert_not_equals.ts';
+import { init } from '../build/esm/index.js';
+
+function resetGlobals(): void {
+  getMainCarrier().__SENTRY__ = undefined;
+}
+
+// Captured before any init() so the patch assertion below compares against the
+// genuinely unpatched function; the patch installs once per module graph.
+const unpatchedServe = Deno.serve;
+
+function initPatchedServeWithoutClient(): void {
+  // Install the Deno.serve patch, then unbind the client. The patch is installed by
+  // `Client.init()`, which a directly-constructed client also runs without ever
+  // calling `setCurrentClient` — so a live patch with no bound client is a real state.
+  resetGlobals();
+  init({ dsn: 'https://username@domain/123' });
+  assertNotEquals(Deno.serve, unpatchedServe, 'Deno.serve was not patched; test would pass vacuously');
+  resetGlobals();
+}
+
+Deno.test('Deno.serve keeps serving when no client is bound', async () => {
+  initPatchedServeWithoutClient();
+
+  const abortController = new AbortController();
+  let onListen: ((_: unknown) => void) | undefined = undefined;
+  const p = new Promise(resolve => (onListen = resolve));
+  const server = Deno.serve({ port: 0, signal: abortController.signal, onListen }, () => {
+    return new Response('Hello World');
+  });
+  await p;
+
+  const response = await fetch(`http://localhost:${server.addr.port}/test`);
+  assertEquals(response.status, 200);
+  assertEquals(await response.text(), 'Hello World');
+
+  abortController.abort();
+  await server.finished;
+});
+
+Deno.test('Deno.serve propagates handler errors as 500 when no client is bound', async () => {
+  initPatchedServeWithoutClient();
+
+  const abortController = new AbortController();
+  let onListen: ((_: unknown) => void) | undefined = undefined;
+  const p = new Promise(resolve => (onListen = resolve));
+  const server = Deno.serve({ port: 0, signal: abortController.signal, onListen }, () => {
+    throw new Error('handler blew up');
+  });
+  await p;
+
+  const response = await fetch(`http://localhost:${server.addr.port}/boom`);
+  assertEquals(response.status, 500);
+  await response.body?.cancel();
+
+  abortController.abort();
+  await server.finished;
+});