Fixed issue where requestSts wasn't including the Studio cookie in it

.changeset/wicked-scissors-yell.md

@@ -0,0 +1,5 @@
+---
+"@firebase/auth": patch
+---
+
+Fixed issue where requestSts wasn't including the Firebase Studio cookie in it

packages/auth/src/api/authentication/token.test.ts

@@ -95,6 +95,26 @@ describe('requestStsToken', () => {
     );
   });
 
+  it('should use credentials: include when using Firebase Studio', async () => {
+    const mock = fetch.mock(endpoint, {
+      'access_token': 'new-access-token',
+      'expires_in': '3600',
+      'refresh_token': 'new-refresh-token'
+    });
+
+    auth._logFramework('Mythical');
+    auth.emulatorConfig = {
+      host: 'something.cloudworkstations.dev',
+      port: 443,
+      options: { disableWarnings: false },
+      protocol: 'https'
+    };
+    await requestStsToken(auth, 'some-refresh-token');
+    expect(mock.calls[0].fullRequest?.credentials).to.eq('include');
+
+    auth.emulatorConfig = null;
+  });
+
   it('should include whatever headers come from auth impl', async () => {
     sinon.stub(auth, '_getAdditionalHeaders').returns(
       Promise.resolve({

packages/auth/src/api/authentication/token.ts

@@ -17,7 +17,7 @@
 
 /* eslint-disable camelcase */
 
-import { querystring } from '@firebase/util';
+import { isCloudWorkstation, querystring } from '@firebase/util';
 
 import {
   _getFinalTarget,
@@ -84,11 +84,18 @@ export async function requestStsToken(
         const headers = await (auth as AuthInternal)._getAdditionalHeaders();
         headers[HttpHeader.CONTENT_TYPE] = 'application/x-www-form-urlencoded';
 
-        return FetchProvider.fetch()(url, {
+        const options: RequestInit = {
           method: HttpMethod.POST,
           headers,
           body
-        });
+        };
+        if (
+          auth.emulatorConfig &&
+          isCloudWorkstation(auth.emulatorConfig.host)
+        ) {
+          options.credentials = 'include';
+        }
+        return FetchProvider.fetch()(url, options);
       }
     );