fix(hono): Return the existing client on repeated init in Bun and Deno (#24520)

On Bun and Deno, `init()` warned when Sentry was already initialized but
then initialized again, replacing the client. Anything buffered on the
first client was dropped and its integrations stayed installed against
it.

Both now keep the warning and return the existing client, as the Node
entry already does. Node's behavior is unchanged (it only logs in debug
mode, since it is initialized from an instrument file); Cloudflare
initializes per request through `withSentry` and is not affected.

Closes #24049

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

Author: Shubham-Padkonde

packages/hono/src/bun/sdk.ts

@@ -13,13 +13,16 @@ import { LOW_QUALITY_TRANSACTION_PATTERNS } from '../shared/lowQualityTransactio
  * When manually calling `init`, add the `honoIntegration` to the `integrations` array to set up the Hono integration.
  */
 export function init(options: HonoBunOptions): Client | undefined {
-  if (getClient()) {
+  const existingClient = getClient();
+  if (existingClient) {
     consoleSandbox(() => {
       // eslint-disable-next-line no-console
       console.warn(
         '[Sentry] Sentry is already initialized. Sentry should only be initialized once, through the `sentry()` middleware. Remove the `Sentry.init()` call, if one exists.',
       );
     });
+    // Re-initializing would replace the client and drop anything buffered on it
+    return existingClient;
   }
 
   applySdkMetadata(options, 'hono', ['hono', 'bun']);

packages/hono/src/deno/sdk.ts

@@ -13,13 +13,16 @@ import { LOW_QUALITY_TRANSACTION_PATTERNS } from '../shared/lowQualityTransactio
  * When manually calling `init`, add the `honoIntegration` to the `integrations` array to set up the Hono integration.
  */
 export function init(options: HonoDenoOptions): Client | undefined {
-  if (getClient()) {
+  const existingClient = getClient();
+  if (existingClient) {
     consoleSandbox(() => {
       // eslint-disable-next-line no-console
       console.warn(
         '[Sentry] Sentry is already initialized. Sentry should only be initialized once, through the `sentry()` middleware. Remove the `Sentry.init()` call, if one exists.',
       );
     });
+    // Re-initializing would replace the client and drop anything buffered on it
+    return existingClient;
   }
 
   applySdkMetadata(options, 'hono', ['hono', 'deno']);

packages/hono/test/bun/middleware.test.ts

@@ -171,14 +171,22 @@ describe('Hono Bun Middleware', () => {
   });
 
   describe('double-init guard', () => {
-    it('still calls init even when Sentry is already initialized', () => {
+    it('does not re-initialize when Sentry is already initialized', () => {
       const fakeClient = { getOptions: () => ({}) };
       getClientMock.mockReturnValue(fakeClient as unknown as SentryCore.Client);
 
       const app = new Hono();
       sentry(app, { dsn: 'https://public@dsn.ingest.sentry.io/1337' });
 
-      expect(initBunMock).toHaveBeenCalledTimes(1);
+      expect(initBunMock).not.toHaveBeenCalled();
+    });
+
+    it('returns the existing client when Sentry is already initialized', () => {
+      const fakeClient = { getOptions: () => ({}) };
+      getClientMock.mockReturnValue(fakeClient as unknown as SentryCore.Client);
+
+      expect(init({ dsn: 'https://public@dsn.ingest.sentry.io/1337' })).toBe(fakeClient);
+      expect(initBunMock).not.toHaveBeenCalled();
     });
 
     it('emits a console.warn directing to remove the duplicate init call when Sentry is already initialized', () => {

packages/hono/test/deno/middleware.test.ts

@@ -171,14 +171,22 @@ describe('Hono Deno Middleware', () => {
   });
 
   describe('double-init guard', () => {
-    it('still calls init even when Sentry is already initialized', () => {
+    it('does not re-initialize when Sentry is already initialized', () => {
       const fakeClient = { getOptions: () => ({}) };
       getClientMock.mockReturnValue(fakeClient as unknown as SentryCore.Client);
 
       const app = new Hono();
       sentry(app, { dsn: 'https://public@dsn.ingest.sentry.io/1337' });
 
-      expect(initDenoMock).toHaveBeenCalledTimes(1);
+      expect(initDenoMock).not.toHaveBeenCalled();
+    });
+
+    it('returns the existing client when Sentry is already initialized', () => {
+      const fakeClient = { getOptions: () => ({}) };
+      getClientMock.mockReturnValue(fakeClient as unknown as SentryCore.Client);
+
+      expect(init({ dsn: 'https://public@dsn.ingest.sentry.io/1337' })).toBe(fakeClient);
+      expect(initDenoMock).not.toHaveBeenCalled();
     });
 
     it('emits a console.warn directing to remove the duplicate init call when Sentry is already initialized', () => {