From ad87890b2e92f3f4092bbf9a70ab0d439d40ce31 Mon Sep 17 00:00:00 2001
From: Sam Minnee <sam@silverstripe.com>
Date: Tue, 2 Oct 2018 09:54:06 +1300
Subject: [PATCH] =?UTF-8?q?FIX:=20Don=E2=80=99t=20change=20state=20in=20Ar?=
 =?UTF-8?q?rayList::getIterator()?=
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This prevents the map-to-ArrayData conversion from changing object
state and making the result of toArray() non-deterministic.

Fixes #2636. Other solutions were suggested on that ticket, but there is
no way of putting special code in for a SSViewer-specific iterator, and
having object state pre-emptively converted to ArrayData would
be an SS5-level change.
---
 src/ORM/ArrayList.php | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/src/ORM/ArrayList.php b/src/ORM/ArrayList.php
index 70edb5b9e..9ac0558e2 100644
--- a/src/ORM/ArrayList.php
+++ b/src/ORM/ArrayList.php
@@ -84,12 +84,13 @@ class ArrayList extends ViewableData implements SS_List, Filterable, Sortable, L
      */
     public function getIterator()
     {
-        foreach ($this->items as $i => $item) {
-            if (is_array($item)) {
-                $this->items[$i] = new ArrayData($item);
-            }
-        }
-        return new ArrayIterator($this->items);
+        $items = array_map(
+            function ($item) {
+                return is_array($item) ? new ArrayData($item) : $item;
+            },
+            $this->items
+        );
+        return new ArrayIterator($items);
     }
 
     /**