Do not chain the tasks of getting auth and appcheck tokens.

Author: ehsannas

firebase-firestore/src/main/java/com/google/firebase/firestore/remote/FirestoreCallCredentials.java

@@ -14,6 +14,7 @@
 
 package com.google.firebase.firestore.remote;
 
+import com.google.android.gms.tasks.Task;
 import com.google.android.gms.tasks.Tasks;
 import com.google.firebase.FirebaseApiNotAvailableException;
 import com.google.firebase.firestore.auth.CredentialsProvider;
@@ -52,66 +53,75 @@ public void thisUsesUnstableApi() {}
   @Override
   public void applyRequestMetadata(
       RequestInfo requestInfo, Executor executor, final MetadataApplier metadataApplier) {
-    authProvider
-        .getToken()
-        .continueWithTask(
+    Task<Metadata> authTask =
+        authProvider
+            .getToken()
+            .continueWithTask(
+                executor,
+                task -> {
+                  Metadata metadata = new Metadata();
+                  if (task.isSuccessful()) {
+                    String token = task.getResult();
+                    Logger.debug(LOG_TAG, "Successfully fetched auth token.");
+                    if (token != null) {
+                      metadata.put(AUTHORIZATION_HEADER, "Bearer " + token);
+                    }
+                    return Tasks.forResult(metadata);
+                  } else {
+                    Exception exception = task.getException();
+                    if (exception instanceof FirebaseApiNotAvailableException) {
+                      Logger.debug(
+                          LOG_TAG, "Firebase Auth API not available, not using authentication.");
+                      return Tasks.forResult(metadata);
+                    } else if (exception instanceof FirebaseNoSignedInUserException) {
+                      Logger.debug(LOG_TAG, "No user signed in, not using authentication.");
+                      return Tasks.forResult(metadata);
+                    } else {
+                      Logger.warn(LOG_TAG, "Failed to get auth token: %s.", exception);
+                      return Tasks.forException(exception);
+                    }
+                  }
+                });
+
+    Task<Metadata> appCheckTask =
+        appCheckProvider
+            .getToken()
+            .continueWithTask(
+                executor,
+                task -> {
+                  Metadata metadata = new Metadata();
+                  if (task.isSuccessful()) {
+                    String token = task.getResult();
+                    if (token != null && !token.isEmpty()) {
+                      Logger.debug(LOG_TAG, "Successfully fetched AppCheck token.");
+                      metadata.put(X_FIREBASE_APPCHECK, token);
+                    }
+                    return Tasks.forResult(metadata);
+                  } else {
+                    Exception exception = task.getException();
+                    if (exception instanceof FirebaseApiNotAvailableException) {
+                      Logger.debug(LOG_TAG, "Firebase AppCheck API not available.");
+                      return Tasks.forResult(metadata);
+                    } else {
+                      Logger.warn(LOG_TAG, "Failed to get AppCheck token: %s.", exception);
+                      return Tasks.forException(exception);
+                    }
+                  }
+                });
+
+    Tasks.whenAll(authTask, appCheckTask)
+        .addOnSuccessListener(
             executor,
-            task -> {
-              Metadata metadata = new Metadata();
-              if (task.isSuccessful()) {
-                String token = task.getResult();
-                Logger.debug(LOG_TAG, "Successfully fetched auth token.");
-                if (token != null) {
-                  metadata.put(AUTHORIZATION_HEADER, "Bearer " + token);
-                }
-                return Tasks.forResult(metadata);
-              } else {
-                Exception exception = task.getException();
-                if (exception instanceof FirebaseApiNotAvailableException) {
-                  Logger.debug(
-                      LOG_TAG, "Firebase Auth API not available, not using authentication.");
-                  return Tasks.forResult(metadata);
-                } else if (exception instanceof FirebaseNoSignedInUserException) {
-                  Logger.debug(LOG_TAG, "No user signed in, not using authentication.");
-                  return Tasks.forResult(metadata);
-                } else {
-                  Logger.warn(LOG_TAG, "Failed to get auth token: %s.", exception);
-                  return Tasks.forException(exception);
-                }
-              }
+            unused -> {
+              Metadata authMetadata = authTask.getResult();
+              Metadata appCheckMetadata = appCheckTask.getResult();
+              authMetadata.merge(appCheckMetadata);
+              metadataApplier.apply(authMetadata);
             })
         .addOnFailureListener(
             executor,
             exception -> {
-              // If the auth task has failed, there is no point in getting the AppCheck token.
               metadataApplier.fail(Status.UNAUTHENTICATED.withCause(exception));
-            })
-        .addOnSuccessListener(
-            executor,
-            metadata -> {
-              // If the auth task has succeeded, try to get the AppCheck token as well.
-              appCheckProvider
-                  .getToken()
-                  .addOnSuccessListener(
-                      executor,
-                      appCheckToken -> {
-                        if (appCheckToken != null && !appCheckToken.isEmpty()) {
-                          Logger.debug(LOG_TAG, "Successfully fetched AppCheck token.");
-                          metadata.put(X_FIREBASE_APPCHECK, appCheckToken);
-                        }
-                        metadataApplier.apply(metadata);
-                      })
-                  .addOnFailureListener(
-                      executor,
-                      exception -> {
-                        if (exception instanceof FirebaseApiNotAvailableException) {
-                          Logger.debug(LOG_TAG, "Firebase AppCheck API not available.");
-                          metadataApplier.apply(metadata);
-                        } else {
-                          Logger.warn(LOG_TAG, "Failed to get AppCheck token: %s.", exception);
-                          metadataApplier.fail(Status.UNAUTHENTICATED.withCause(exception));
-                        }
-                      });
             });
   }
 }