FIX Respect explicit casting before casting arrays

src/Forms/Form.php

@@ -521,13 +521,13 @@ public function setFieldMessage(
         return $this;
     }
 
-    public function castingHelper($field)
+    public function castingHelper($field, bool $useFallback = true)
     {
         // Override casting for field message
         if (strcasecmp($field ?? '', 'Message') === 0 && ($helper = $this->getMessageCastingHelper())) {
             return $helper;
         }
-        return parent::castingHelper($field);
+        return parent::castingHelper($field, $useFallback);
     }
 
     /**

src/Forms/FormField.php

@@ -790,13 +790,13 @@ public function securityTokenEnabled()
         return $form->getSecurityToken()->isEnabled();
     }
 
-    public function castingHelper($field)
+    public function castingHelper($field, bool $useFallback = true)
     {
         // Override casting for field message
         if (strcasecmp($field ?? '', 'Message') === 0 && ($helper = $this->getMessageCastingHelper())) {
             return $helper;
         }
-        return parent::castingHelper($field);
+        return parent::castingHelper($field, $useFallback);
     }
 
     /**

src/Forms/ReadonlyField.php

@@ -56,15 +56,15 @@ public function Type()
         return 'readonly';
     }
 
-    public function castingHelper($field)
+    public function castingHelper($field, bool $useFallback = true)
     {
         // Get dynamic cast for 'Value' field
         if (strcasecmp($field ?? '', 'Value') === 0) {
             return $this->getValueCast();
         }
 
         // Fall back to default casting
-        return parent::castingHelper($field);
+        return parent::castingHelper($field, $useFallback);
     }
 
     public function getSchemaStateDefaults()

src/ORM/DataObject.php

@@ -2947,7 +2947,7 @@ public function setCastedField($fieldName, $value)
     /**
      * {@inheritdoc}
      */
-    public function castingHelper($field)
+    public function castingHelper($field, bool $useFallback = true)
     {
         $fieldSpec = static::getSchema()->fieldSpec(static::class, $field);
         if ($fieldSpec) {
@@ -2965,7 +2965,7 @@ public function castingHelper($field)
             }
         }
 
-        return parent::castingHelper($field);
+        return parent::castingHelper($field, $useFallback);
     }
 
     /**

src/ORM/FieldType/DBComposite.php

@@ -319,14 +319,14 @@ public function dbObject($field)
         return $fieldObject;
     }
 
-    public function castingHelper($field)
+    public function castingHelper($field, bool $useFallback = true)
     {
         $fields = $this->compositeDatabaseFields();
         if (isset($fields[$field])) {
             return $fields[$field];
         }
 
-        return parent::castingHelper($field);
+        return parent::castingHelper($field, $useFallback);
     }
 
     public function getIndexSpecs()

src/View/ViewableData.php

@@ -385,10 +385,11 @@ public function setCustomisedObj(ViewableData $object)
      * for a field on this object. This helper will be a subclass of DBField.
      *
      * @param string $field
-     * @return string Casting helper As a constructor pattern, and may include arguments.
+     * @param bool $useFallback If true, fall back on the default casting helper if there isn't an explicit one.
+     * @return string|null Casting helper As a constructor pattern, and may include arguments.
      * @throws Exception
      */
-    public function castingHelper($field)
+    public function castingHelper($field, bool $useFallback = true)
     {
         // Get casting if it has been configured.
         // DB fields and PHP methods are all case insensitive so we normalise casing before checking.
@@ -399,20 +400,41 @@ public function castingHelper($field)
         }
 
         // If no specific cast is declared, fall back to failover.
-        // Note that if there is a failover, the default_cast will always
+        $failover = $this->getFailover();
+        if ($failover) {
+            $cast = $failover->castingHelper($field, $useFallback);
+            if ($cast) {
+                return $cast;
+            }
+        }
+
+        if ($useFallback) {
+            return $this->defaultCastingHelper($field);
+        }
+
+        return null;
+    }
+
+    /**
+     * Return the default "casting helper" for use when no explicit casting helper is defined.
+     * This helper will be a subclass of DBField. See castingHelper()
+     */
+    protected function defaultCastingHelper(string $field): string
+    {
+        // If there is a failover, the default_cast will always
         // be drawn from this object instead of the top level object.
         $failover = $this->getFailover();
         if ($failover) {
-            $cast = $failover->castingHelper($field);
+            $cast = $failover->defaultCastingHelper($field);
             if ($cast) {
                 return $cast;
             }
         }
 
-        // Fall back to default_cast
+        // Fall back to raw default_cast
         $default = $this->config()->get('default_cast');
         if (empty($default)) {
-            throw new Exception("No default_cast");
+            throw new Exception('No default_cast');
         }
         return $default;
     }
@@ -559,15 +581,25 @@ public function obj($fieldName, $arguments = [], $cache = false, $cacheName = nu
             $value = $this->$fieldName;
         }
 
+        // Try to cast object if we have an explicit cast set
+        if (!is_object($value)) {
+            $castingHelper = $this->castingHelper($fieldName, false);
+            if ($castingHelper !== null) {
+                $valueObject = Injector::inst()->create($castingHelper, $fieldName);
+                $valueObject->setValue($value, $this);
+                $value = $valueObject;
+            }
+        }
+
         // Wrap list arrays in ViewableData so templates can handle them
         if (is_array($value) && array_is_list($value)) {
             $value = ArrayList::create($value);
         }
 
-        // Cast object
+        // Fallback on default casting
         if (!is_object($value)) {
             // Force cast
-            $castingHelper = $this->castingHelper($fieldName);
+            $castingHelper = $this->defaultCastingHelper($fieldName);
             $valueObject = Injector::inst()->create($castingHelper, $fieldName);
             $valueObject->setValue($value, $this);
             $value = $valueObject;

tests/php/View/ViewableDataTest.php

@@ -6,6 +6,7 @@
 use SilverStripe\ORM\FieldType\DBField;
 use SilverStripe\Dev\SapphireTest;
 use SilverStripe\ORM\ArrayList;
+use SilverStripe\ORM\FieldType\DBText;
 use SilverStripe\View\ArrayData;
 use SilverStripe\View\SSViewer;
 use SilverStripe\View\Tests\ViewableDataTest\ViewableDataTestExtension;
@@ -59,6 +60,9 @@ public function testRequiresCasting()
 
         $this->assertInstanceOf(ViewableDataTest\RequiresCasting::class, $caster->obj('alwaysCasted'));
         $this->assertInstanceOf(ViewableDataTest\Caster::class, $caster->obj('noCastingInformation'));
+
+        $this->assertInstanceOf(DBText::class, $caster->obj('arrayOne'));
+        $this->assertInstanceOf(ArrayList::class, $caster->obj('arrayTwo'));
     }
 
     public function testFailoverRequiresCasting()

tests/php/View/ViewableDataTest/Castable.php

@@ -7,13 +7,13 @@
 
 class Castable extends ViewableData implements TestOnly
 {
-
     private static $default_cast = Caster::class;
 
     private static $casting = [
         'alwaysCasted' => RequiresCasting::class,
         'castedUnsafeXML' => UnescapedCaster::class,
         'test' => 'Text',
+        'arrayOne' => 'Text',
     ];
 
     public $test = 'test';
@@ -25,6 +25,16 @@ public function alwaysCasted()
         return 'alwaysCasted';
     }
 
+    public function arrayOne()
+    {
+        return ['value1', 'value2'];
+    }
+
+    public function arrayTwo()
+    {
+        return ['value1', 'value2'];
+    }
+
     public function noCastingInformation()
     {
         return 'noCastingInformation';