fix: the return type hint was incorrect here and would cause an error…

… e.g. when mapping records to objects

src/framework/Result.php

@@ -39,9 +39,9 @@ public function __construct(PreparedStatement $statement, int $batch_size, array
     }
 
     /**
-     * @return array<string,mixed>|null first record of the record-set (or NULL, if the record-set is empty)
+     * @return mixed|null first record of the record-set (or NULL, if the record-set is empty)
      */
-    public function firstRow(): array|null
+    public function firstRow(): mixed
     {
         foreach ($this->createIterator(1) as $record) {
             return $record; // break from loop immediately after fetching the first record

test/test-unit.php

@@ -696,14 +696,14 @@ function () {
         $mappers = [new RecordMapper(function (array $record) use (&$calls) {
             $calls[] = $record;
 
-            return $record;
+            return (object) $record;
         })];
 
         $result = new Result($mock_statement, 20, $mappers);
 
         $record = $result->firstRow();
 
-        eq($record, ['id' => 1], 'should return first row');
+        eq($record->id, 1, 'should return first result');
 
         eq($calls, [['id' => 1]], 'should process precisely one record (disregarding batch size)');
     }