FIX: CheckboxSetField can now save into DBMultiEnum

Fixes https://github.com/silverstripe/silverstripe-framework/issues/1489

src/Forms/MultiSelectField.php

@@ -4,6 +4,7 @@ namespace SilverStripe\Forms;
 
 use SilverStripe\ORM\DataObject;
 use SilverStripe\ORM\DataObjectInterface;
+use SilverStripe\ORM\FieldType\DBMultiEnum;
 use SilverStripe\ORM\Relation;
 
 /**
@@ -98,7 +99,15 @@ abstract class MultiSelectField extends SelectField
             $value = array_values($relation->getIDList());
             parent::setValue($value);
         } elseif ($record->hasField($fieldName)) {
-            $value = $this->stringDecode($record->$fieldName);
+            // Load dataValue from field... a CSV for DBMultiEnum
+            if ($record->obj($fieldName) instanceof DBMultiEnum) {
+                $value = $this->csvDecode($record->$fieldName);
+
+            // ... JSON-encoded string for other fields
+            } else {
+                $value = $this->stringDecode($record->$fieldName);
+            }
+
             parent::setValue($value);
         }
     }
@@ -129,8 +138,14 @@ abstract class MultiSelectField extends SelectField
             // Save ids into relation
             $relation->setByIDList($items);
         } elseif ($record->hasField($fieldName)) {
-            // Save dataValue into field
+            // Save dataValue into field... a CSV for DBMultiEnum
-            $record->$fieldName = $this->stringEncode($items);
+            if ($record->obj($fieldName) instanceof DBMultiEnum) {
+                $record->$fieldName = $this->csvEncode($items);
+
+            // ... JSON-encoded string for other fields
+            } else {
+                $record->$fieldName = $this->stringEncode($items);
+            }
         }
     }
 
@@ -169,6 +184,45 @@ abstract class MultiSelectField extends SelectField
         throw new \InvalidArgumentException("Invalid string encoded value for multi select field");
     }
 
+    /**
+     * Encode a list of values into a string as a comma separated list.
+     * Commas will be stripped from the items passed in
+     *
+     * @param array $value
+     * @return string|null
+     */
+    protected function csvEncode($value)
+    {
+        if (!$value) {
+            return null;
+        }
+        return implode(
+            ',',
+            array_map(
+                function ($x) {
+                    return str_replace(',', '', $x);
+                },
+                array_values($value)
+            )
+        );
+    }
+
+    /**
+     * Decode a list of values from a comma separated string.
+     * Spaces are trimmed
+     *
+     * @param string $value
+     * @return array
+     */
+    protected function csvDecode($value)
+    {
+        if (!$value) {
+            return [];
+        }
+
+        return preg_split('/\s*,\s*/', trim($value));
+    }
+
     /**
      * Validate this field
      *

tests/php/Forms/CheckboxFieldtest/MutiEnumArticle.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace SilverStripe\Forms\Tests\CheckboxSetFieldTest;
+
+use SilverStripe\Dev\TestOnly;
+use SilverStripe\ORM\DataObject;
+
+class MultiEnumArticle extends DataObject implements TestOnly
+{
+    private static $table_name = 'CheckboxSetFieldTest_MultiEnumArticle';
+
+    private static $db = array(
+        "Content" => "Text",
+        "Colours" => "MultiEnum('Red,Blue,Green')",
+    );
+}

tests/php/Forms/CheckboxSetFieldMultiEnumTest.php

@@ -0,0 +1,98 @@
+<?php
+
+namespace SilverStripe\Forms\Tests;
+
+use SilverStripe\Forms\Tests\CheckboxSetFieldTest\MultiEnumArticle;
+use SilverStripe\ORM\DB;
+use SilverStripe\Dev\SapphireTest;
+use SilverStripe\Control\Controller;
+use SilverStripe\Forms\CheckboxSetField;
+use SilverStripe\Forms\FieldList;
+use SilverStripe\Forms\Form;
+use SilverStripe\ORM\Connect\MySQLDatabase;
+
+class CheckboxSetFieldMulitEnumTest extends SapphireTest
+{
+
+    protected $usesDatabase = true;
+
+    public static function getExtraDataObjects()
+    {
+        // Don't add this for other database
+        if (DB::get_conn() instanceof MySQLDatabase) {
+            return [
+                MultiEnumArticle::class,
+            ];
+        }
+    }
+
+    public function setUp()
+    {
+        if (!(DB::get_conn() instanceof MySQLDatabase)) {
+            $this->markTestSkipped('DBMultiEnum only supported by MySQL');
+            return;
+        }
+        parent::setUp();
+    }
+
+    public function tearDown()
+    {
+        if (!(DB::get_conn() instanceof MySQLDatabase)) {
+            return;
+        }
+        parent::tearDown();
+    }
+
+    public function testLoadDataFromMultiEnum()
+    {
+        $article = new MultiEnumArticle();
+        $article->Colours = 'Red,Green';
+
+        $field = new CheckboxSetField(
+            'Colours',
+            'Colours',
+            [
+                'Red' => 'Red',
+                'Blue' => 'Blue',
+                'Green' => 'Green',
+            ]
+        );
+
+        $form = new Form(
+            Controller::curr(),
+            'Form',
+            new FieldList($field),
+            new FieldList()
+        );
+        $form->loadDataFrom($article);
+        $value = $field->Value();
+        $this->assertEquals(['Red', 'Green'], $value);
+    }
+
+    public function testSavingIntoMultiEnum()
+    {
+        $field = new CheckboxSetField(
+            'Colours',
+            'Colours',
+            [
+                'Red' => 'Red',
+                'Blue' => 'Blue',
+                'Green' => 'Green',
+            ]
+        );
+        $article = new MultiEnumArticle();
+        $field->setValue(array('Red' => 'Red', 'Blue' => 'Blue'));
+        $field->saveInto($article);
+        $article->write();
+
+        $dbValue = DB::query(
+            sprintf(
+                'SELECT "Colours" FROM "CheckboxSetFieldTest_MultiEnumArticle" WHERE "ID" = %s',
+                $article->ID
+            )
+        )->value();
+
+        // JSON encoded values
+        $this->assertEquals('Red,Blue', $dbValue);
+    }
+}