Don't switch network status to UNKNOWN during user change (#3700)

.changeset/cold-impalas-drop.md

@@ -0,0 +1,5 @@
+---
+"@firebase/firestore": patch
+---
+
+Fixes a bug that caused the client to not raise snapshots from cache if a user change happened while the network connection was disabled.

packages/firestore/exp/src/api/components.ts

@@ -98,6 +98,7 @@ export async function setOnlineComponentProvider(
   // The CredentialChangeListener of the online component provider takes
   // precedence over the offline component provider.
   firestore._setCredentialChangeListener(user =>
+    // TODO(firestoreexp): This should be enqueueRetryable.
     firestore._queue.enqueueAndForget(() =>
       onlineComponentProvider.remoteStore.handleCredentialChange(user)
     )

packages/firestore/src/remote/remote_store.ts

@@ -791,21 +791,24 @@ export class RemoteStore implements TargetMetadataProvider {
 
   async handleCredentialChange(user: User): Promise<void> {
     this.asyncQueue.verifyOperationInProgress();
+    debugAssert(
+      !!this.remoteSyncer.handleCredentialChange,
+      'handleCredentialChange() not set'
+    );
+
+    logDebug(LOG_TAG, 'RemoteStore received new credentials');
+    const canUseNetwork = this.canUseNetwork();
 
     // Tear down and re-create our network streams. This will ensure we get a
     // fresh auth token for the new user and re-fill the write pipeline with
     // new mutations from the LocalStore (since mutations are per-user).
-    logDebug(LOG_TAG, 'RemoteStore received new credentials');
     this.offlineCauses.add(OfflineCause.CredentialChange);
-
     await this.disableNetworkInternal();
-    this.onlineStateTracker.set(OnlineState.Unknown);
-    debugAssert(
-      !!this.remoteSyncer.handleCredentialChange,
-      'handleCredentialChange() not set'
-    );
+    if (canUseNetwork) {
+      // Don't set the network status to Unknown if we are offline.
+      this.onlineStateTracker.set(OnlineState.Unknown);
+    }
     await this.remoteSyncer.handleCredentialChange(user);
-
     this.offlineCauses.delete(OfflineCause.CredentialChange);
     await this.enableNetworkInternal();
   }

packages/firestore/test/unit/specs/offline_spec.test.ts

@@ -239,4 +239,21 @@ describeSpec('Offline:', [], () => {
       );
     }
   );
+
+  specTest('Client stays offline during credential change', [], () => {
+    // Reproduces a bug that caused the client to switch to OnlineState
+    // `Unknown` during a credential change.
+
+    const query1 = query('collection');
+    return (
+      spec()
+        .disableNetwork()
+        .changeUser('user1')
+        .userListens(query1)
+        // Client is still offline and we raise a `fromCache` event immediately
+        .expectEvents(query1, {
+          fromCache: true
+        })
+    );
+  });
 });