Add AsListIterator to remove gaps in arrays

Author: alcaeus

psalm-baseline.xml

@@ -68,6 +68,11 @@
       <code><![CDATA[$context[$this->protocol]['options']]]></code>
     </MixedArrayAccess>
   </file>
+  <file src="src/Model/AsListIterator.php">
+    <InvalidTemplateParam occurrences="1">
+      <code>AsListIterator</code>
+    </InvalidTemplateParam>
+  </file>
   <file src="src/Model/BSONArray.php">
     <MixedAssignment>
       <code>$this[$key]</code>

src/Model/AsListIterator.php

@@ -0,0 +1,51 @@
+<?php
+/*
+ * Copyright 2023-present MongoDB, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace MongoDB\Model;
+
+use IteratorIterator;
+use Traversable;
+
+/**
+ * @internal
+ *
+ * @template TValue
+ * @template-extends IteratorIterator<int, TValue, Traversable<mixed, TValue>>
+ */
+final class AsListIterator extends IteratorIterator
+{
+    private int $index = 0;
+
+    public function key(): int
+    {
+        return $this->index;
+    }
+
+    public function next(): void
+    {
+        $this->index++;
+
+        parent::next();
+    }
+
+    public function rewind(): void
+    {
+        $this->index = 0;
+
+        parent::rewind();
+    }
+}