Extract new function into a separate interface for BC

Author: Marijus Kilmanas

src/Firebase/Auth.php

@@ -59,7 +59,7 @@
 /**
  * @internal
  */
-final class Auth implements Contract\Auth
+final class Auth implements Contract\Auth, Contract\Transitional\FederatedUserFetcher
 {
     private readonly Parser $jwtParser;
 

src/Firebase/Contract/Auth.php

@@ -125,15 +125,6 @@ public function getUserByEmail(Stringable|string $email): UserRecord;
      */
     public function getUserByPhoneNumber(Stringable|string $phoneNumber): UserRecord;
 
-    /**
-     * @param Stringable|non-empty-string $providerId
-     * @param Stringable|non-empty-string $providerUid
-     *
-     * @throws Exception\AuthException
-     * @throws Exception\FirebaseException
-     */
-    public function getUserByProviderUid(Stringable|string $providerId, Stringable|string $providerUid): UserRecord;
-
     /**
      * @throws Exception\AuthException
      * @throws Exception\FirebaseException

src/Firebase/Contract/Transitional/FederatedUserFetcher.php

@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Kreait\Firebase\Contract\Transitional;
+
+use Kreait\Firebase\Auth\UserRecord;
+use Kreait\Firebase\Exception;
+use Stringable;
+
+/**
+ * @TODO: This interface is intended to be integrated into the Auth interface on the next major release.
+ */
+interface FederatedUserFetcher
+{
+    /**
+     * @param Stringable|non-empty-string $providerId
+     * @param Stringable|non-empty-string $providerUid
+     *
+     * @throws Exception\AuthException
+     * @throws Exception\FirebaseException
+     */
+    public function getUserByProviderUid(Stringable|string $providerId, Stringable|string $providerUid): UserRecord;
+}