bugfix: unserliaze accountid

.changes/nextrelease/creds-unserialize.json

@@ -0,0 +1,7 @@
+[
+  {
+    "type": "bugfix",
+    "category": "Credentials",
+    "description": "Fixes issue with unserializing cached credentials without newly added `accountId` property"
+  }
+]

src/Credentials/Credentials.php

@@ -110,7 +110,7 @@ public function __unserialize($data)
         $this->secret = $data['secret'];
         $this->token = $data['token'];
         $this->expires = $data['expires'];
-        $this->accountId = $data['accountId'];
+        $this->accountId = $data['accountId'] ?? null;
     }
 
     /**

tests/Credentials/CredentialsTest.php

@@ -71,4 +71,23 @@ public function testIsInstanceOfIdentity()
         $credentials = new Credentials('key-value', 'secret-value');
         $this->assertInstanceOf(AwsCredentialIdentity::class, $credentials);
     }
+
+    public function testCanUnserializeWithoutAccountId()
+    {
+        $oldSerializedData = json_encode([
+            'key'     => 'test-key',
+            'secret'  => 'test-secret',
+            'token'   => 'test-token',
+            'expires' => time() + 3600
+        ]);
+
+        $credentials = new Credentials('foo', 'bar');
+        $credentials->unserialize($oldSerializedData);
+
+        $this->assertEquals('test-key', $credentials->getAccessKeyId());
+        $this->assertEquals('test-secret', $credentials->getSecretKey());
+        $this->assertEquals('test-token', $credentials->getSecurityToken());
+        $this->assertNotNull($credentials->getExpiration());
+        $this->assertNull($credentials->getAccountId());
+    }
 }