[Finder] Fix string key on rows get when preserveKey disabled

Author: samsonasik

src/Finder.php

@@ -11,6 +11,7 @@
 
 use function current;
 use function end;
+use function is_string;
 use function iterator_to_array;
 use function key;
 use function prev;
@@ -137,8 +138,14 @@ public static function rows(iterable $data, callable $filter, bool $preserveKey
                 continue;
             }
 
-            $rows[$preserveKey ? $key : $newKey] = $datum;
-            ++$newKey;
+            if (is_string($key)) {
+                $rowKey = $key;
+            } else {
+                $rowKey = $preserveKey ? $key : $newKey;
+                ++$newKey;
+            }
+
+            $rows[$rowKey] = $datum;
         }
 
         return $rows;

tests/FinderTest.php

@@ -281,6 +281,11 @@ public static function rowsDataProvider(): array
                 static fn($datum): bool => $datum < 5,
                 [],
             ],
+            [
+                [6, 7, 'foo' => 8, 9],
+                static fn($datum): bool => $datum > 7,
+                ['foo' => 8, 9],
+            ],
         ];
     }