From 9ce6d91b76e525a6fc81e02023e9e53cdf82e047 Mon Sep 17 00:00:00 2001
From: Serge Latyntcev <dnsl48@gmail.com>
Date: Thu, 22 Nov 2018 12:11:18 +1300
Subject: [PATCH] FIX / TreeMultiselectField::objectForKey handles list of IDs
 correctly

---
 src/Forms/TreeMultiselectField.php           | 6 +++++-
 tests/php/Forms/TreeMultiselectFieldTest.php | 6 ++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/Forms/TreeMultiselectField.php b/src/Forms/TreeMultiselectField.php
index 422b5739a..372890f6b 100644
--- a/src/Forms/TreeMultiselectField.php
+++ b/src/Forms/TreeMultiselectField.php
@@ -279,10 +279,14 @@ class TreeMultiselectField extends TreeDropdownField
          * of numeric types with string values, issuing a database error.
          *
          * This fix is not ideal, but supposed to keep backward compatibility for SS4.
-         * Since SS5 this method should be removed and NULL should be used instead of 'unchanged'.
+         *
+         * In 5.0 this method to be removed and NULL should be used instead of 'unchanged' (or an empty array. to be decided).
+         * In 5.0 this class to be refactored so that $this->value is always an array of values (or null)
          */
         if ($this->getKeyField() === 'ID' && $key === 'unchanged') {
             $key = null;
+        } elseif (is_string($key)) {
+            $key = preg_split('/\s*,\s*/', trim($key));
         }
 
         return parent::objectForKey($key);
diff --git a/tests/php/Forms/TreeMultiselectFieldTest.php b/tests/php/Forms/TreeMultiselectFieldTest.php
index ffff5491f..2686b71a2 100644
--- a/tests/php/Forms/TreeMultiselectFieldTest.php
+++ b/tests/php/Forms/TreeMultiselectFieldTest.php
@@ -20,6 +20,9 @@ class TreeMultiselectFieldTest extends SapphireTest
         $schemaStateDefaults = $field->getSchemaStateDefaults();
         $this->assertArraySubset(['id' => 'TestTree', 'name' => 'TestTree', 'value' => 'unchanged'], $schemaStateDefaults, $strict = true);
 
+        $items = $field->getItems();
+        $this->assertCount(0, $items, $message = 'there must be no items selected');
+
         $html = $field->performReadonlyTransformation()->Field();
 
         $this->assertEquals(
@@ -45,6 +48,9 @@ HTML
         $schemaStateDefaults = $field->getSchemaStateDefaults();
         $this->assertArraySubset(['id' => 'TestTree', 'name' => 'TestTree', 'value' => [$asdf->ID, $subfolderfile1->ID]], $schemaStateDefaults, $strict = true);
 
+        $items = $field->getItems();
+        $this->assertCount(2, $items, $message = 'there must be exactly 2 items selected');
+
         $html = (string)$field->performReadonlyTransformation()->Field();
 
         $this->assertEquals(