Fix style issues

src/CredentialSource/FileSource.php

@@ -29,7 +29,6 @@ class FileSource implements ExternalAccountCredentialSourceInterface
     private string $file;
     private ?string $format;
     private ?string $subjectTokenFieldName;
-    private string $cacheKey;
 
     /**
      * @param string $file                  The file to read the subject token from.

src/CredentialSource/UrlSource.php

@@ -104,6 +104,6 @@ public function fetchSubjectToken(callable $httpHandler = null): string
      */
     public function getCacheKey(): string
     {
-        return $this->url . ":" . $this->subjectTokenFieldName;
+        return $this->url . ':' . $this->subjectTokenFieldName;
     }
 }

src/Credentials/ExternalAccountCredentials.php

@@ -54,13 +54,6 @@ class ExternalAccountCredentials implements
     private ?string $projectId;
     private string $universeDomain;
 
-    /**
-     * Used to calculate the Cache Key for caching
-     *
-     * @var array<mixed>
-     */
-    private array $jsonKey;
-
     /**
      * @param string|string[] $scope   The scope of the access request, expressed either as an array
      *                                 or as a space-delimited string.
@@ -129,8 +122,6 @@ public function __construct(
                 'workforce_pool_user_project should not be set for non-workforce pool credentials.'
             );
         }
-
-        $this->jsonKey = $jsonKey;
     }
 
     /**
@@ -375,26 +366,4 @@ private function isWorkforcePool(): bool
         $regex = '#//iam\.googleapis\.com/locations/[^/]+/workforcePools/#';
         return preg_match($regex, $this->auth->getAudience()) === 1;
     }
-
-    /**
-     * @param array<mixed> $arr
-     *
-     * @return array<string>
-     */
-    private function flattenJsonKey(array $arr): array
-    {
-        $result = [];
-
-        foreach($arr as $key => $val) {
-            if (is_array($val)) {
-                $result = array_merge($result, $this->flattenJsonKey($val));
-            } elseif ($val === '') {
-                continue;
-            } else {
-                array_push($result, $val);
-            }
-        }
-
-        return $result;
-    }
 }

src/OAuth2.php

@@ -684,7 +684,7 @@ public function fetchAuthToken(callable $httpHandler = null, $headers = [])
 
     /**
      * @deprecated
-     * 
+     *
      * Obtains a key that can used to cache the results of #fetchAuthToken.
      *
      * The key is derived from the scopes.
@@ -707,7 +707,7 @@ public function getCacheKey()
 
     /**
      * Gets this instance's SubjectTokenFetcher
-     * 
+     *
      * @return null|ExternalAccountCredentialSourceInterface
      */
     public function getSubjectTokenFetcher(): null|ExternalAccountCredentialSourceInterface