bug #63144 [Form] Fix OrderedHashMap auto-increment logic with mixed keys (yoeunes)

nicolas-grekas · nicolas-grekas · commit 0e7c9fb10bb6 · 2026-01-22T21:17:27.000+01:00
This PR was merged into the 6.4 branch. Discussion ---------- [Form] Fix `OrderedHashMap` auto-increment logic with mixed keys | Q | A | ------------- | --- | Branch? | 6.4 | Bug fix? | yes | New feature? | no | Deprecations? | no | Issues | - | License | MIT When `OrderedHashMap` has mixed integer and string keys, appending a new element overwrites existing integer keys instead of generating a new key: ```php $map = new OrderedHashMap(); $map[0] = 'zero'; $map[1] = 'one'; $map['foo'] = 'bar'; $map[] = 'new'; // overwrites key 1 instead of creating key 2 ``` Commits ------- 10f9f01 [Form] Fix OrderedHashMap auto-increment logic with mixed keys
diff --git a/src/Symfony/Component/Form/Tests/Util/OrderedHashMapTest.php b/src/Symfony/Component/Form/Tests/Util/OrderedHashMapTest.php
@@ -524,4 +524,36 @@ public function testCount()
 
         $this->assertCount(2, $map);
     }
+
+    public function testAppendDoesNotOverwriteExistingNumericKeysWhenStringKeysExist()
+    {
+        $map = new OrderedHashMap();
+        $map[0] = 'zero';
+        $map[1] = 'one';
+        $map['foo'] = 'bar';
+        $map[] = 'new';
+
+        $this->assertSame('one', $map[1]);
+        $this->assertSame('new', $map[2]);
+    }
+
+    public function testUpdateNullValueDoesNotChangeElementPosition()
+    {
+        $map = new OrderedHashMap();
+        $map['first'] = null;
+        $map['second'] = 2;
+        $map['first'] = null;
+
+        $this->assertSame(['first' => null, 'second' => 2], iterator_to_array($map));
+    }
+
+    public function testUpdateFromNullValueDoesNotChangeElementPosition()
+    {
+        $map = new OrderedHashMap();
+        $map['first'] = null;
+        $map['second'] = 2;
+        $map['first'] = 1;
+
+        $this->assertSame(['first' => 1, 'second' => 2], iterator_to_array($map));
+    }
 }
diff --git a/src/Symfony/Component/Form/Util/OrderedHashMap.php b/src/Symfony/Component/Form/Util/OrderedHashMap.php
@@ -120,16 +120,11 @@ public function offsetGet(mixed $key): mixed
 
     public function offsetSet(mixed $key, mixed $value): void
     {
-        if (null === $key || !isset($this->elements[$key])) {
-            if (null === $key) {
-                $key = [] === $this->orderedKeys
-                    // If the array is empty, use 0 as key
-                    ? 0
-                    // Imitate PHP behavior of generating a key that equals
-                    // the highest existing integer key + 1
-                    : 1 + (int) max($this->orderedKeys);
-            }
-
+        if (null === $key) {
+            $this->elements[] = $value;
+            $key = array_key_last($this->elements);
+            $this->orderedKeys[] = (string) $key;
+        } elseif (!\array_key_exists($key, $this->elements)) {
             $this->orderedKeys[] = (string) $key;
         }
 
