Fix error_handler return type declaration

src/Composer/Util/ErrorHandler.php

@@ -33,6 +33,7 @@ class ErrorHandler
      *
      * @static
      * @throws \ErrorException
+     * @return bool
      */
     public static function handle($level, $message, $file, $line)
     {
@@ -63,6 +64,8 @@ class ErrorHandler
                 }, array_slice(debug_backtrace(), 2))));
             }
         }
+
+        return true;
     }
 
     /**

src/Composer/Util/RemoteFilesystem.php

@@ -321,6 +321,8 @@ class RemoteFilesystem
                 $errorMessage .= "\n";
             }
             $errorMessage .= preg_replace('{^file_get_contents\(.*?\): }', '', $msg);
+
+            return true;
         });
         try {
             $result = $this->getRemoteContents($originUrl, $fileUrl, $ctx, $http_response_header);
@@ -494,6 +496,8 @@ class RemoteFilesystem
                     $errorMessage .= "\n";
                 }
                 $errorMessage .= preg_replace('{^file_put_contents\(.*?\): }', '', $msg);
+
+                return true;
             });
             $result = (bool) file_put_contents($fileName, $result);
             restore_error_handler();