diff --git a/src/Forms/Form.php b/src/Forms/Form.php
index 7f9b2251f..db7044ac9 100644
--- a/src/Forms/Form.php
+++ b/src/Forms/Form.php
@@ -12,7 +12,6 @@ use SilverStripe\Control\RequestHandler;
 use SilverStripe\Control\Session;
 use SilverStripe\Core\ClassInfo;
 use SilverStripe\Core\Injector\Injector;
-use SilverStripe\ORM\DataObject;
 use SilverStripe\ORM\DataObjectInterface;
 use SilverStripe\ORM\FieldType\DBHTMLText;
 use SilverStripe\ORM\ValidationResult;
@@ -136,7 +135,7 @@ class Form extends ViewableData implements HasRequestHandler
     /**
      * Populated by {@link loadDataFrom()}.
      *
-     * @var DataObject|null
+     * @var ViewableData|null
      */
     protected $record;
 
@@ -1223,10 +1222,10 @@ class Form extends ViewableData implements HasRequestHandler
     }
 
     /**
-     * Returns the DataObject that has given this form its data
+     * Returns the record that has given this form its data
      * through {@link loadDataFrom()}.
      *
-     * @return DataObject
+     * @return ViewableData
      */
     public function getRecord()
     {
@@ -1285,7 +1284,7 @@ class Form extends ViewableData implements HasRequestHandler
     const MERGE_AS_SUBMITTED_VALUE  = 0b1000;
 
     /**
-     * Load data from the given DataObject or array.
+     * Load data from the given record or array.
      *
      * It will call $object->MyField to get the value of MyField.
      * If you passed an array, it will call $object[MyField].
@@ -1306,7 +1305,7 @@ class Form extends ViewableData implements HasRequestHandler
      * @uses FormField::setSubmittedValue()
      * @uses FormField::setValue()
      *
-     * @param array|DataObject $data
+     * @param array|ViewableData $data
      * @param int $mergeStrategy
      *  For every field, {@link $data} is interrogated whether it contains a relevant property/key, and
      *  what that property/key's value is.
@@ -1351,7 +1350,7 @@ class Form extends ViewableData implements HasRequestHandler
 
         // If an object is passed, save it for historical reference through {@link getRecord()}
         // Also use this to determine if we are loading a submitted form, or loading
-        // from a dataobject
+        // from a record
         $submitted = true;
         if (is_object($data)) {
             $this->record = $data;
@@ -1480,7 +1479,7 @@ class Form extends ViewableData implements HasRequestHandler
      * Save the contents of this form into the given data object.
      * It will make use of setCastedField() to do this.
      *
-     * @param DataObjectInterface $dataObject The object to save data into
+     * @param ViewableData&DataObjectInterface $dataObject The object to save data into
      * @param FieldList $fieldList An optional list of fields to process.  This can be useful when you have a
      * form that has some fields that save to one object, and some that save to another.
      */
@@ -1523,7 +1522,7 @@ class Form extends ViewableData implements HasRequestHandler
      * {@link FieldList->dataFields()}, which filters out
      * any form-specific data like form-actions.
      * Calls {@link FormField->dataValue()} on each field,
-     * which returns a value suitable for insertion into a DataObject
+     * which returns a value suitable for insertion into a record
      * property.
      *
      * @return array
diff --git a/src/Forms/FormField.php b/src/Forms/FormField.php
index dc14e477b..e8c821f65 100644
--- a/src/Forms/FormField.php
+++ b/src/Forms/FormField.php
@@ -8,13 +8,13 @@ use SilverStripe\Control\Controller;
 use SilverStripe\Control\RequestHandler;
 use SilverStripe\Core\ClassInfo;
 use SilverStripe\Core\Convert;
-use SilverStripe\ORM\DataObject;
 use SilverStripe\ORM\DataObjectInterface;
 use SilverStripe\ORM\FieldType\DBField;
 use SilverStripe\ORM\FieldType\DBHTMLText;
 use SilverStripe\ORM\ValidationResult;
 use SilverStripe\View\AttributesHTML;
 use SilverStripe\View\SSViewer;
+use SilverStripe\View\ViewableData;
 
 /**
  * Represents a field in a form.
@@ -454,11 +454,11 @@ class FormField extends RequestHandler
     }
 
     /**
-     * Method to save this form field into the given {@link DataObject}.
+     * Method to save this form field into the given record.
      *
      * By default, makes use of $this->dataValue()
      *
-     * @param DataObject|DataObjectInterface $record DataObject to save data into
+     * @param ViewableData|DataObjectInterface $record Record to save data into
      */
     public function saveInto(DataObjectInterface $record)
     {
@@ -697,7 +697,7 @@ class FormField extends RequestHandler
      * or a submitted form value they should override setSubmittedValue() instead.
      *
      * @param mixed $value Either the parent object, or array of source data being loaded
-     * @param array|DataObject $data {@see Form::loadDataFrom}
+     * @param array|ViewableData $data {@see Form::loadDataFrom}
      * @return $this
      */
     public function setValue($value, $data = null)
@@ -712,7 +712,7 @@ class FormField extends RequestHandler
      * data formats.
      *
      * @param mixed $value
-     * @param array|DataObject $data
+     * @param array|ViewableData $data
      * @return $this
      */
     public function setSubmittedValue($value, $data = null)
diff --git a/src/Forms/GridField/GridField.php b/src/Forms/GridField/GridField.php
index 19210651c..2590aa758 100644
--- a/src/Forms/GridField/GridField.php
+++ b/src/Forms/GridField/GridField.php
@@ -20,11 +20,14 @@ use SilverStripe\Forms\GridField\FormAction\SessionStore;
 use SilverStripe\Forms\GridField\FormAction\StateStore;
 use SilverStripe\ORM\ArrayList;
 use SilverStripe\ORM\DataList;
-use SilverStripe\ORM\DataObject;
 use SilverStripe\ORM\DataObjectInterface;
 use SilverStripe\ORM\FieldType\DBField;
+use SilverStripe\ORM\Filterable;
+use SilverStripe\ORM\Limitable;
+use SilverStripe\ORM\Sortable;
 use SilverStripe\ORM\SS_List;
 use SilverStripe\View\HTML;
+use SilverStripe\View\ViewableData;
 
 /**
  * Displays a {@link SS_List} in a grid format.
@@ -83,12 +86,12 @@ class GridField extends FormField
     /**
      * Data source.
      *
-     * @var SS_List
+     * @var SS_List&Filterable&Sortable&Limitable
      */
     protected $list = null;
 
     /**
-     * Class name of the DataObject that the GridField will display.
+     * Class name of the records that the GridField will display.
      *
      * Defaults to the value of $this->list->dataClass.
      *
@@ -205,7 +208,7 @@ class GridField extends FormField
     }
 
     /**
-     * Returns a data class that is a DataObject type that this GridField should look like.
+     * Returns the class name of the record type that this GridField should contain.
      *
      * @return string
      *
@@ -374,7 +377,7 @@ class GridField extends FormField
     /**
      * Set the data source.
      *
-     * @param SS_List $list
+     * @param SS_List&Filterable&Sortable&Limitable $list
      *
      * @return $this
      */
@@ -388,7 +391,7 @@ class GridField extends FormField
     /**
      * Get the data source.
      *
-     * @return SS_List
+     * @return SS_List&Filterable&Sortable&Limitable
      */
     public function getList()
     {
@@ -398,7 +401,7 @@ class GridField extends FormField
     /**
      * Get the data source after applying every {@link GridField_DataManipulator} to it.
      *
-     * @return SS_List
+     * @return SS_List&Filterable&Sortable&Limitable
      */
     public function getManipulatedList()
     {
@@ -461,7 +464,7 @@ class GridField extends FormField
         if (($request instanceof NullHTTPRequest) && Controller::has_curr()) {
             $request = Controller::curr()->getRequest();
         }
-        
+
         $stateStr = $this->getStateManager()->getStateFromRequest($this, $request);
         if ($stateStr) {
             $oldState = $this->getState(false);
@@ -744,7 +747,7 @@ class GridField extends FormField
     /**
      * @param int $total
      * @param int $index
-     * @param DataObject $record
+     * @param ViewableData $record
      * @param array $attributes
      * @param string $content
      *
@@ -762,7 +765,7 @@ class GridField extends FormField
     /**
      * @param int $total
      * @param int $index
-     * @param DataObject $record
+     * @param ViewableData $record
      * @param array $attributes
      * @param string $content
      *
@@ -780,7 +783,7 @@ class GridField extends FormField
     /**
      * @param int $total
      * @param int $index
-     * @param DataObject $record
+     * @param ViewableData $record
      *
      * @return array
      */
@@ -798,7 +801,7 @@ class GridField extends FormField
     /**
      * @param int $total
      * @param int $index
-     * @param DataObject $record
+     * @param ViewableData $record
      *
      * @return array
      */
@@ -869,7 +872,7 @@ class GridField extends FormField
     /**
      * Get the value from a column.
      *
-     * @param DataObject $record
+     * @param ViewableData $record
      * @param string $column
      *
      * @return string
@@ -922,7 +925,7 @@ class GridField extends FormField
      * Use of this method ensures that any special rules around the data for this gridfield are
      * followed.
      *
-     * @param DataObject $record
+     * @param ViewableData $record
      * @param string $fieldName
      *
      * @return mixed
@@ -949,7 +952,7 @@ class GridField extends FormField
     /**
      * Get extra columns attributes used as HTML attributes.
      *
-     * @param DataObject $record
+     * @param ViewableData $record
      * @param string $column
      *
      * @return array
diff --git a/src/Forms/GridField/GridFieldAddNewButton.php b/src/Forms/GridField/GridFieldAddNewButton.php
index dffcabdcd..67d943657 100644
--- a/src/Forms/GridField/GridFieldAddNewButton.php
+++ b/src/Forms/GridField/GridFieldAddNewButton.php
@@ -2,7 +2,9 @@
 
 namespace SilverStripe\Forms\GridField;
 
+use LogicException;
 use SilverStripe\Control\Controller;
+use SilverStripe\Core\ClassInfo;
 use SilverStripe\ORM\DataObject;
 use SilverStripe\ORM\RelationList;
 use SilverStripe\View\ArrayData;
@@ -12,8 +14,7 @@ use SilverStripe\View\SSViewer;
  * This component provides a button for opening the add new form provided by
  * {@link GridFieldDetailForm}.
  *
- * Only returns a button if {@link DataObject->canCreate()} for this record
- * returns true.
+ * Only returns a button if canCreate() for this record returns true.
  */
 class GridFieldAddNewButton extends AbstractGridFieldComponent implements GridField_HTMLProvider
 {
@@ -36,7 +37,16 @@ class GridFieldAddNewButton extends AbstractGridFieldComponent implements GridFi
 
     public function getHTMLFragments($gridField)
     {
-        $singleton = singleton($gridField->getModelClass());
+        $modelClass = $gridField->getModelClass();
+        $singleton = singleton($modelClass);
+
+        if (!$singleton->hasMethod('canCreate')) {
+            throw new LogicException(
+                __CLASS__ . ' cannot be used with models that do not implement canCreate().'
+                . " Remove this component from your GridField or implement canCreate() on $modelClass"
+            );
+        }
+
         $context = [];
         if ($gridField->getList() instanceof RelationList) {
             $record = $gridField->getForm()->getRecord();
@@ -51,7 +61,7 @@ class GridFieldAddNewButton extends AbstractGridFieldComponent implements GridFi
 
         if (!$this->buttonName) {
             // provide a default button name, can be changed by calling {@link setButtonName()} on this component
-            $objectName = $singleton->i18n_singular_name();
+            $objectName = $singleton->hasMethod('i18n_singular_name') ? $singleton->i18n_singular_name() : ClassInfo::shortName($singleton);
             $this->buttonName = _t('SilverStripe\\Forms\\GridField\\GridField.Add', 'Add {name}', ['name' => $objectName]);
         }
 
diff --git a/src/Forms/GridField/GridFieldDataColumns.php b/src/Forms/GridField/GridFieldDataColumns.php
index a852e3107..41b0713d9 100644
--- a/src/Forms/GridField/GridFieldDataColumns.php
+++ b/src/Forms/GridField/GridFieldDataColumns.php
@@ -4,7 +4,8 @@ namespace SilverStripe\Forms\GridField;
 
 use SilverStripe\Core\Convert;
 use InvalidArgumentException;
-use SilverStripe\ORM\DataObject;
+use LogicException;
+use SilverStripe\View\ViewableData;
 
 /**
  * @see GridField
@@ -87,7 +88,15 @@ class GridFieldDataColumns extends AbstractGridFieldComponent implements GridFie
     public function getDisplayFields($gridField)
     {
         if (!$this->displayFields) {
-            return singleton($gridField->getModelClass())->summaryFields();
+            $modelClass = $gridField->getModelClass();
+            $singleton = singleton($modelClass);
+            if (!$singleton->hasMethod('summaryFields')) {
+                throw new LogicException(
+                    'Cannot dynamically determine columns. Pass the column names to setDisplayFields()'
+                    . " or implement a summaryFields() method on $modelClass"
+                );
+            }
+            return $singleton->summaryFields();
         }
         return $this->displayFields;
     }
@@ -146,7 +155,7 @@ class GridFieldDataColumns extends AbstractGridFieldComponent implements GridFie
      * HTML for the column, content of the <td> element.
      *
      * @param GridField $gridField
-     * @param DataObject $record Record displayed in this row
+     * @param ViewableData $record Record displayed in this row
      * @param string $columnName
      * @return string HTML for the column. Return NULL to skip.
      */
@@ -180,7 +189,7 @@ class GridFieldDataColumns extends AbstractGridFieldComponent implements GridFie
      * Attributes for the element containing the content returned by {@link getColumnContent()}.
      *
      * @param  GridField $gridField
-     * @param  DataObject $record displayed in this row
+     * @param  ViewableData $record displayed in this row
      * @param  string $columnName
      * @return array
      */
@@ -216,7 +225,7 @@ class GridFieldDataColumns extends AbstractGridFieldComponent implements GridFie
     /**
      * Translate a Object.RelationName.ColumnName $columnName into the value that ColumnName returns
      *
-     * @param DataObject $record
+     * @param ViewableData $record
      * @param string $columnName
      * @return string|null - returns null if it could not found a value
      */
@@ -269,7 +278,7 @@ class GridFieldDataColumns extends AbstractGridFieldComponent implements GridFie
     /**
      *
      * @param GridField $gridField
-     * @param DataObject $item
+     * @param ViewableData $item
      * @param string $fieldName
      * @param string $value
      * @return string
diff --git a/src/Forms/GridField/GridFieldDeleteAction.php b/src/Forms/GridField/GridFieldDeleteAction.php
index 35c3c1e69..a0d81c322 100644
--- a/src/Forms/GridField/GridFieldDeleteAction.php
+++ b/src/Forms/GridField/GridFieldDeleteAction.php
@@ -2,9 +2,12 @@
 
 namespace SilverStripe\Forms\GridField;
 
+use LogicException;
 use SilverStripe\Control\Controller;
-use SilverStripe\ORM\DataObject;
+use SilverStripe\ORM\DataList;
+use SilverStripe\ORM\DataObjectInterface;
 use SilverStripe\ORM\ValidationException;
+use SilverStripe\View\ViewableData;
 
 /**
  * This class is a {@link GridField} component that adds a delete action for
@@ -72,13 +75,12 @@ class GridFieldDeleteAction extends AbstractGridFieldComponent implements GridFi
     /**
      *
      * @param GridField $gridField
-     * @param DataObject $record
+     * @param DataObjectInterface&ViewableData $record
      * @param string $columnName
      * @return string|null the attribles for the action
      */
     public function getExtraData($gridField, $record, $columnName)
     {
-
         $field = $this->getRemoveAction($gridField, $record, $columnName);
 
         if ($field) {
@@ -105,7 +107,7 @@ class GridFieldDeleteAction extends AbstractGridFieldComponent implements GridFi
      * Return any special attributes that will be used for FormField::create_tag()
      *
      * @param GridField $gridField
-     * @param DataObject $record
+     * @param DataObjectInterface&ViewableData $record
      * @param string $columnName
      * @return array
      */
@@ -153,7 +155,7 @@ class GridFieldDeleteAction extends AbstractGridFieldComponent implements GridFi
     /**
      *
      * @param GridField $gridField
-     * @param DataObject $record
+     * @param DataObjectInterface&ViewableData $record
      * @param string $columnName
      * @return string|null the HTML for the column
      */
@@ -179,29 +181,39 @@ class GridFieldDeleteAction extends AbstractGridFieldComponent implements GridFi
      */
     public function handleAction(GridField $gridField, $actionName, $arguments, $data)
     {
+        $list = $gridField->getList();
         if ($actionName == 'deleterecord' || $actionName == 'unlinkrelation') {
-            /** @var DataObject $item */
-            $item = $gridField->getList()->byID($arguments['RecordID']);
+            /** @var DataObjectInterface&ViewableData $item */
+            $item = $list->byID($arguments['RecordID']);
             if (!$item) {
                 return;
             }
 
             if ($actionName == 'deleterecord') {
+                $this->checkForRequiredMethod($item, 'canDelete');
+
                 if (!$item->canDelete()) {
                     throw new ValidationException(
                         _t(__CLASS__ . '.DeletePermissionsFailure', "No delete permissions")
                     );
                 }
 
+                if (!($list instanceof DataList)) {
+                    // We need to make sure to exclude the item since the list items have already been determined.
+                    // This must happen before deletion while the item still has its ID set.
+                    $gridField->setList($list->exclude(['ID' => $item->ID]));
+                }
                 $item->delete();
             } else {
+                $this->checkForRequiredMethod($item, 'canEdit');
+
                 if (!$item->canEdit()) {
                     throw new ValidationException(
                         _t(__CLASS__ . '.EditPermissionsFailure', "No permission to unlink record")
                     );
                 }
 
-                $gridField->getList()->remove($item);
+                $list->remove($item);
             }
         }
     }
@@ -209,16 +221,19 @@ class GridFieldDeleteAction extends AbstractGridFieldComponent implements GridFi
     /**
      *
      * @param GridField $gridField
-     * @param DataObject $record
+     * @param DataObjectInterface&ViewableData $record
      * @param string $columnName
      * @return GridField_FormAction|null
      */
     private function getRemoveAction($gridField, $record, $columnName)
     {
         if ($this->getRemoveRelation()) {
+            $this->checkForRequiredMethod($record, 'canEdit');
+
             if (!$record->canEdit()) {
                 return null;
             }
+
             $title = _t(__CLASS__ . '.UnlinkRelation', "Unlink");
 
             $field = GridField_FormAction::create(
@@ -233,9 +248,12 @@ class GridFieldDeleteAction extends AbstractGridFieldComponent implements GridFi
                 ->setDescription($title)
                 ->setAttribute('aria-label', $title);
         } else {
+            $this->checkForRequiredMethod($record, 'canDelete');
+
             if (!$record->canDelete()) {
                 return null;
             }
+
             $title = _t(__CLASS__ . '.Delete', "Delete");
 
             $field = GridField_FormAction::create(
@@ -274,4 +292,20 @@ class GridFieldDeleteAction extends AbstractGridFieldComponent implements GridFi
         $this->removeRelation = (bool) $removeRelation;
         return $this;
     }
+
+    /**
+     * Checks if a required method exists - and if not, throws an exception.
+     *
+     * @throws LogicException if the required method doesn't exist
+     */
+    private function checkForRequiredMethod($record, string $method): void
+    {
+        if (!$record->hasMethod($method)) {
+            $modelClass = get_class($record);
+            throw new LogicException(
+                __CLASS__ . " cannot be used with models that don't implement {$method}()."
+                . " Remove this component from your GridField or implement {$method}() on $modelClass"
+            );
+        }
+    }
 }
diff --git a/src/Forms/GridField/GridFieldDetailForm.php b/src/Forms/GridField/GridFieldDetailForm.php
index 0497dc564..07299cc93 100644
--- a/src/Forms/GridField/GridFieldDetailForm.php
+++ b/src/Forms/GridField/GridFieldDetailForm.php
@@ -3,6 +3,7 @@
 namespace SilverStripe\Forms\GridField;
 
 use Closure;
+use LogicException;
 use SilverStripe\Control\Director;
 use SilverStripe\Control\HTTPRequest;
 use SilverStripe\Control\HTTPResponse;
@@ -13,10 +14,11 @@ use SilverStripe\Core\ClassInfo;
 use SilverStripe\Core\Extensible;
 use SilverStripe\Core\Injector\Injector;
 use SilverStripe\Forms\FieldList;
+use SilverStripe\Forms\FieldsValidator;
 use SilverStripe\Forms\Validator;
 use SilverStripe\ORM\DataList;
 use SilverStripe\ORM\DataObject;
-use SilverStripe\ORM\Filterable;
+use SilverStripe\View\ViewableData;
 
 /**
  * Provides view and edit forms at GridField-specific URLs.
@@ -62,7 +64,7 @@ class GridFieldDetailForm extends AbstractGridFieldComponent implements GridFiel
     protected $validator;
 
     /**
-     * @var FieldList Falls back to {@link DataObject->getCMSFields()} if not defined.
+     * @var FieldList Falls back to {@link $record->getCMSFields()} if not defined.
      */
     protected $fields;
 
@@ -143,28 +145,31 @@ class GridFieldDetailForm extends AbstractGridFieldComponent implements GridFiel
 
         // if no validator has been set on the GridField then use the Validators from the record.
         if (!$this->getValidator()) {
-            $this->setValidator($record->getCMSCompositeValidator());
+            if ($record->hasMethod('getCMSCompositeValidator')) {
+                $validator = $record->getCMSCompositeValidator();
+            } else {
+                $validator = FieldsValidator::create();
+            }
+            $this->setValidator($validator);
         }
 
         return $handler->handleRequest($request);
     }
 
-    /**
-     * @param GridField $gridField
-     * @param HTTPRequest $request
-     * @return DataObject|null
-     */
-    protected function getRecordFromRequest(GridField $gridField, HTTPRequest $request): ?DataObject
+    protected function getRecordFromRequest(GridField $gridField, HTTPRequest $request): ?ViewableData
     {
-        /** @var DataObject $record */
+        /** @var ViewableData $record */
         if (is_numeric($request->param('ID'))) {
-            /** @var Filterable $dataList */
             $dataList = $gridField->getList();
             $record = $dataList->byID($request->param('ID'));
         } else {
             $record = Injector::inst()->create($gridField->getModelClass());
         }
 
+        if ($record && !$record->hasField('ID')) {
+            throw new LogicException(get_class($record) . ' must have an ID field.');
+        }
+
         return $record;
     }
 
@@ -174,7 +179,7 @@ class GridFieldDetailForm extends AbstractGridFieldComponent implements GridFiel
      * This only works when the list passed to the GridField is a {@link DataList}.
      *
      * @param $gridField The current GridField
-     * @param $id The ID of the DataObject to open
+     * @param $id The ID of the record to open
      */
     public function getLostRecordRedirection(GridField $gridField, HTTPRequest $request, ?int $id = null): ?string
     {
@@ -216,7 +221,7 @@ class GridFieldDetailForm extends AbstractGridFieldComponent implements GridFiel
      * Build a request handler for the given record
      *
      * @param GridField $gridField
-     * @param DataObject $record
+     * @param ViewableData $record
      * @param RequestHandler $requestHandler
      * @return GridFieldDetailForm_ItemRequest
      */
@@ -248,7 +253,7 @@ class GridFieldDetailForm extends AbstractGridFieldComponent implements GridFiel
     }
 
     /**
-     * @return String
+     * @return string
      */
     public function getTemplate()
     {
@@ -266,7 +271,7 @@ class GridFieldDetailForm extends AbstractGridFieldComponent implements GridFiel
     }
 
     /**
-     * @return String
+     * @return string
      */
     public function getName()
     {
@@ -276,8 +281,8 @@ class GridFieldDetailForm extends AbstractGridFieldComponent implements GridFiel
     /**
      * Enable redirection to missing records.
      *
-     * If a GridField shows a filtered list, and the DataObject is not in the list but exists in the
-     * database, and the DataObject has a CMSEditLink method, then the system will redirect to the
+     * If a GridField shows a filtered list, and the record is not in the list but exists in the
+     * database, and the record has a CMSEditLink method, then the system will redirect to the
      * URL returned by that method.
      */
     public function setRedirectMissingRecords(bool $redirectMissingRecords): self
diff --git a/src/Forms/GridField/GridFieldDetailForm_ItemRequest.php b/src/Forms/GridField/GridFieldDetailForm_ItemRequest.php
index e3b5b8c3b..d0e6c6c54 100644
--- a/src/Forms/GridField/GridFieldDetailForm_ItemRequest.php
+++ b/src/Forms/GridField/GridFieldDetailForm_ItemRequest.php
@@ -9,6 +9,7 @@ use SilverStripe\Control\HTTPRequest;
 use SilverStripe\Control\HTTPResponse;
 use SilverStripe\Control\RequestHandler;
 use SilverStripe\Core\Convert;
+use SilverStripe\Core\ClassInfo;
 use SilverStripe\Forms\CompositeField;
 use SilverStripe\Forms\FieldList;
 use SilverStripe\Forms\Form;
@@ -17,6 +18,7 @@ use SilverStripe\Forms\HiddenField;
 use SilverStripe\Forms\LiteralField;
 use SilverStripe\ORM\ArrayList;
 use SilverStripe\ORM\DataObject;
+use SilverStripe\ORM\DataObjectInterface;
 use SilverStripe\ORM\FieldType\DBHTMLText;
 use SilverStripe\ORM\HasManyList;
 use SilverStripe\ORM\ManyManyList;
@@ -28,6 +30,7 @@ use SilverStripe\ORM\ValidationResult;
 use SilverStripe\View\ArrayData;
 use SilverStripe\View\HTML;
 use SilverStripe\View\SSViewer;
+use SilverStripe\View\ViewableData;
 
 class GridFieldDetailForm_ItemRequest extends RequestHandler
 {
@@ -64,7 +67,7 @@ class GridFieldDetailForm_ItemRequest extends RequestHandler
     protected $component;
 
     /**
-     * @var DataObject
+     * @var ViewableData
      */
     protected $record;
 
@@ -96,7 +99,7 @@ class GridFieldDetailForm_ItemRequest extends RequestHandler
      *
      * @param GridField $gridField
      * @param GridFieldDetailForm $component
-     * @param DataObject $record
+     * @param ViewableData&DataObjectInterface $record
      * @param RequestHandler $requestHandler
      * @param string $popupFormName
      */
@@ -125,11 +128,12 @@ class GridFieldDetailForm_ItemRequest extends RequestHandler
      */
     public function view($request)
     {
-        if (!$this->record->canView()) {
+        // Assume item can be viewed if canView() isn't implemented
+        if ($this->record->hasMethod('canView') && !$this->record->canView()) {
             $this->httpError(403, _t(
                 __CLASS__ . '.ViewPermissionsFailure',
                 'It seems you don\'t have the necessary permissions to view "{ObjectTitle}"',
-                ['ObjectTitle' => $this->record->singular_name()]
+                ['ObjectTitle' => $this->getModelName()]
             ));
         }
 
@@ -207,17 +211,25 @@ class GridFieldDetailForm_ItemRequest extends RequestHandler
             }
         }
 
-        if (!$this->record->canView()) {
+        // Assume item can be viewed if canView() isn't implemented
+        if ($this->record->hasMethod('canView') && !$this->record->canView()) {
             $controller = $this->getToplevelController();
             return $controller->httpError(403, _t(
                 __CLASS__ . '.ViewPermissionsFailure',
                 'It seems you don\'t have the necessary permissions to view "{ObjectTitle}"',
-                ['ObjectTitle' => $this->record->singular_name()]
+                ['ObjectTitle' => $this->getModelName()]
             ));
         }
 
         $fields = $this->component->getFields();
         if (!$fields) {
+            if (!$this->record->hasMethod('getCMSFields')) {
+                $modelClass = get_class($this->record);
+                throw new LogicException(
+                    'Cannot dynamically determine form fields. Pass the fields to GridFieldDetailForm::setFields()'
+                    . " or implement a getCMSFields() method on {$modelClass}"
+                );
+            }
             $fields = $this->record->getCMSFields();
         }
 
@@ -241,15 +253,15 @@ class GridFieldDetailForm_ItemRequest extends RequestHandler
 
         $form->loadDataFrom($this->record, $this->record->ID == 0 ? Form::MERGE_IGNORE_FALSEISH : Form::MERGE_DEFAULT);
 
-        if ($this->record->ID && !$this->record->canEdit()) {
+        if ($this->record->ID && (!$this->record->hasMethod('canEdit') || !$this->record->canEdit())) {
             // Restrict editing of existing records
             $form->makeReadonly();
             // Hack to re-enable delete button if user can delete
-            if ($this->record->canDelete()) {
+            if ($this->record->hasMethod('canDelete') && $this->record->canDelete()) {
                 $form->Actions()->fieldByName('action_doDelete')->setReadonly(false);
             }
         } elseif (!$this->record->ID
-            && !$this->record->canCreate(null, $this->getCreateContext())
+            && (!$this->record->hasMethod('canCreate') || !$this->record->canCreate(null, $this->getCreateContext()))
         ) {
             // Restrict creation of new records
             $form->makeReadonly();
@@ -359,7 +371,7 @@ class GridFieldDetailForm_ItemRequest extends RequestHandler
 
         $rightGroup->push($previousAndNextGroup);
 
-        if ($component && $component->getShowAdd() && $this->record->canCreate()) {
+        if ($component && $component->getShowAdd() && $this->record->hasMethod('canCreate') && $this->record->canCreate()) {
             $rightGroup->push(
                 LiteralField::create(
                     'new-record',
@@ -378,7 +390,7 @@ class GridFieldDetailForm_ItemRequest extends RequestHandler
     }
 
     /**
-     * Build the set of form field actions for this DataObject
+     * Build the set of form field actions for the record being handled
      *
      * @return FieldList
      */
@@ -391,8 +403,12 @@ class GridFieldDetailForm_ItemRequest extends RequestHandler
         $majorActions->setFieldHolderTemplate(get_class($majorActions) . '_holder_buttongroup');
         $actions->push($majorActions);
 
-        if ($this->record->ID !== 0) { // existing record
-            if ($this->record->canEdit()) {
+        if ($this->record->ID !== null && $this->record->ID !== 0) { // existing record
+            if ($this->record->hasMethod('canEdit') && $this->record->canEdit()) {
+                if (!($this->record instanceof DataObjectInterface)) {
+                    throw new LogicException(get_class($this->record) . ' must implement ' . DataObjectInterface::class);
+                }
+
                 $noChangesClasses = 'btn-outline-primary font-icon-tick';
                 $majorActions->push(FormAction::create('doSave', _t('SilverStripe\\Forms\\GridField\\GridFieldDetailForm.Save', 'Save'))
                     ->addExtraClass($noChangesClasses)
@@ -402,7 +418,10 @@ class GridFieldDetailForm_ItemRequest extends RequestHandler
                     ->setAttribute('data-text-alternate', _t('SilverStripe\\CMS\\Controllers\\CMSMain.SAVEDRAFT', 'Save')));
             }
 
-            if ($this->record->canDelete()) {
+            if ($this->record->hasMethod('canDelete') && $this->record->canDelete()) {
+                if (!($this->record instanceof DataObjectInterface)) {
+                    throw new LogicException(get_class($this->record) . ' must implement ' . DataObjectInterface::class);
+                }
                 $actions->insertAfter('MajorActions', FormAction::create('doDelete', _t('SilverStripe\\Forms\\GridField\\GridFieldDetailForm.Delete', 'Delete'))
                     ->setUseButtonTag(true)
                     ->addExtraClass('btn-outline-danger btn-hide-outline font-icon-trash-bin action--delete'));
@@ -482,9 +501,9 @@ class GridFieldDetailForm_ItemRequest extends RequestHandler
      * {@see Form::saveInto()}
      *
      * Handles detection of falsey values explicitly saved into the
-     * DataObject by formfields
+     * record by formfields
      *
-     * @param DataObject $record
+     * @param ViewableData $record
      * @param SS_List $list
      * @return array List of data to write to the relation
      */
@@ -510,11 +529,11 @@ class GridFieldDetailForm_ItemRequest extends RequestHandler
         $isNewRecord = $this->record->ID == 0;
 
         // Check permission
-        if (!$this->record->canEdit()) {
+        if (!$this->record->hasMethod('canEdit') || !$this->record->canEdit()) {
             $this->httpError(403, _t(
                 __CLASS__ . '.EditPermissionsFailure',
                 'It seems you don\'t have the necessary permissions to edit "{ObjectTitle}"',
-                ['ObjectTitle' => $this->record->singular_name()]
+                ['ObjectTitle' => $this->getModelName()]
             ));
             return null;
         }
@@ -529,7 +548,7 @@ class GridFieldDetailForm_ItemRequest extends RequestHandler
             'SilverStripe\\Forms\\GridField\\GridFieldDetailForm.Saved',
             'Saved {name} {link}',
             [
-                'name' => $this->record->i18n_singular_name(),
+                'name' => $this->getModelName(),
                 'link' => $link
             ]
         );
@@ -736,12 +755,12 @@ class GridFieldDetailForm_ItemRequest extends RequestHandler
     }
 
     /**
-     * Loads the given form data into the underlying dataobject and relation
+     * Loads the given form data into the underlying record and relation
      *
      * @param array $data
      * @param Form $form
      * @throws ValidationException On error
-     * @return DataObject Saved record
+     * @return ViewableData&DataObjectInterface Saved record
      */
     protected function saveFormIntoRecord($data, $form)
     {
@@ -758,7 +777,7 @@ class GridFieldDetailForm_ItemRequest extends RequestHandler
             $this->record = $this->record->newClassInstance($newClassName);
         }
 
-        // Save form and any extra saved data into this dataobject.
+        // Save form and any extra saved data into this record.
         // Set writeComponents = true to write has-one relations / join records
         $form->saveInto($this->record);
         // https://github.com/silverstripe/silverstripe-assets/issues/365
@@ -780,7 +799,7 @@ class GridFieldDetailForm_ItemRequest extends RequestHandler
     public function doDelete($data, $form)
     {
         $title = $this->record->Title;
-        if (!$this->record->canDelete()) {
+        if (!$this->record->hasMethod('canDelete') || !$this->record->canDelete()) {
             throw new ValidationException(
                 _t('SilverStripe\\Forms\\GridField\\GridFieldDetailForm.DeletePermissionsFailure', "No delete permissions")
             );
@@ -791,7 +810,7 @@ class GridFieldDetailForm_ItemRequest extends RequestHandler
             'SilverStripe\\Forms\\GridField\\GridFieldDetailForm.Deleted',
             'Deleted {type} "{name}"',
             [
-                'type' => $this->record->i18n_singular_name(),
+                'type' => $this->getModelName(),
                 'name' => htmlspecialchars($title ?? '', ENT_QUOTES)
             ]
         );
@@ -862,7 +881,7 @@ class GridFieldDetailForm_ItemRequest extends RequestHandler
     }
 
     /**
-     * @return DataObject
+     * @return ViewableData
      */
     public function getRecord()
     {
@@ -898,7 +917,7 @@ class GridFieldDetailForm_ItemRequest extends RequestHandler
             ]));
         } else {
             $items->push(ArrayData::create([
-                'Title' => _t('SilverStripe\\Forms\\GridField\\GridField.NewRecord', 'New {type}', ['type' => $this->record->i18n_singular_name()]),
+                'Title' => _t('SilverStripe\\Forms\\GridField\\GridField.NewRecord', 'New {type}', ['type' => $this->getModelName()]),
                 'Link' => false
             ]));
         }
@@ -912,4 +931,12 @@ class GridFieldDetailForm_ItemRequest extends RequestHandler
         $this->extend('updateBreadcrumbs', $items);
         return $items;
     }
+
+    private function getModelName(): string
+    {
+        if ($this->record->hasMethod('i18n_singular_name')) {
+            return $this->record->i18n_singular_name();
+        }
+        return ClassInfo::shortName($this->record);
+    }
 }
diff --git a/src/Forms/GridField/GridFieldEditButton.php b/src/Forms/GridField/GridFieldEditButton.php
index 5c52c45d8..e3119fa62 100644
--- a/src/Forms/GridField/GridFieldEditButton.php
+++ b/src/Forms/GridField/GridFieldEditButton.php
@@ -3,9 +3,9 @@
 namespace SilverStripe\Forms\GridField;
 
 use SilverStripe\Control\Controller;
-use SilverStripe\ORM\DataObject;
 use SilverStripe\View\ArrayData;
 use SilverStripe\View\SSViewer;
+use SilverStripe\View\ViewableData;
 
 /**
  * Provides the entry point to editing a single record presented by the
@@ -91,7 +91,7 @@ class GridFieldEditButton extends AbstractGridFieldComponent implements GridFiel
      * Return any special attributes that will be used for FormField::create_tag()
      *
      * @param GridField $gridField
-     * @param DataObject $record
+     * @param ViewableData $record
      * @param string $columnName
      * @return array
      */
@@ -139,7 +139,7 @@ class GridFieldEditButton extends AbstractGridFieldComponent implements GridFiel
 
     /**
      * @param GridField $gridField
-     * @param DataObject $record
+     * @param ViewableData $record
      * @param string $columnName
      * @return string The HTML for the column
      */
diff --git a/src/Forms/GridField/GridFieldExportButton.php b/src/Forms/GridField/GridFieldExportButton.php
index d52d9c821..7a1b63e48 100644
--- a/src/Forms/GridField/GridFieldExportButton.php
+++ b/src/Forms/GridField/GridFieldExportButton.php
@@ -3,12 +3,13 @@
 namespace SilverStripe\Forms\GridField;
 
 use League\Csv\Writer;
+use LogicException;
 use SilverStripe\Control\HTTPRequest;
 use SilverStripe\Control\HTTPResponse;
 use SilverStripe\Core\Config\Config;
 use SilverStripe\ORM\DataList;
-use SilverStripe\ORM\DataObject;
 use SilverStripe\ORM\ArrayList;
+use SilverStripe\View\ViewableData;
 
 /**
  * Adds an "Export list" button to the bottom of a {@link GridField}.
@@ -155,7 +156,15 @@ class GridFieldExportButton extends AbstractGridFieldComponent implements GridFi
             return $dataCols->getDisplayFields($gridField);
         }
 
-        return DataObject::singleton($gridField->getModelClass())->summaryFields();
+        $modelClass = $gridField->getModelClass();
+        $singleton = singleton($modelClass);
+        if (!$singleton->hasMethod('summaryFields')) {
+            throw new LogicException(
+                'Cannot dynamically determine columns. Add a GridFieldDataColumns component to your GridField'
+                . " or implement a summaryFields() method on $modelClass"
+            );
+        }
+        return $singleton->summaryFields();
     }
 
     /**
@@ -225,8 +234,9 @@ class GridFieldExportButton extends AbstractGridFieldComponent implements GridFi
         // Remove limit as the list may be paginated, we want the full list for the export
         $items = $items->limit(null);
 
-        /** @var DataObject $item */
+        /** @var ViewableData $item */
         foreach ($items as $item) {
+            // Assume item can be viewed if canView() isn't implemented
             if (!$item->hasMethod('canView') || $item->canView()) {
                 $columnData = [];
 
diff --git a/src/Forms/GridField/GridFieldFilterHeader.php b/src/Forms/GridField/GridFieldFilterHeader.php
index 8af1a1fa1..edeb9f693 100755
--- a/src/Forms/GridField/GridFieldFilterHeader.php
+++ b/src/Forms/GridField/GridFieldFilterHeader.php
@@ -256,7 +256,15 @@ class GridFieldFilterHeader extends AbstractGridFieldComponent implements GridFi
     public function getSearchContext(GridField $gridField)
     {
         if (!$this->searchContext) {
-            $this->searchContext = singleton($gridField->getModelClass())->getDefaultSearchContext();
+            $modelClass = $gridField->getModelClass();
+            $singleton = singleton($modelClass);
+            if (!$singleton->hasMethod('getDefaultSearchContext')) {
+                throw new LogicException(
+                    'Cannot dynamically instantiate SearchContext. Pass the SearchContext to setSearchContext()'
+                    . " or implement a getDefaultSearchContext() method on $modelClass"
+                );
+            }
+            $this->searchContext = $singleton->getDefaultSearchContext();
         }
 
         return $this->searchContext;
diff --git a/src/Forms/GridField/GridFieldPrintButton.php b/src/Forms/GridField/GridFieldPrintButton.php
index 1fc965808..0cf56bf6b 100644
--- a/src/Forms/GridField/GridFieldPrintButton.php
+++ b/src/Forms/GridField/GridFieldPrintButton.php
@@ -2,16 +2,17 @@
 
 namespace SilverStripe\Forms\GridField;
 
+use LogicException;
 use SilverStripe\Control\HTTPRequest;
 use SilverStripe\Core\Convert;
 use SilverStripe\Core\Extensible;
 use SilverStripe\ORM\ArrayList;
-use SilverStripe\ORM\DataObject;
 use SilverStripe\ORM\FieldType\DBDatetime;
 use SilverStripe\ORM\FieldType\DBHTMLText;
 use SilverStripe\Security\Security;
 use SilverStripe\View\ArrayData;
 use SilverStripe\View\Requirements;
+use SilverStripe\View\ViewableData;
 
 /**
  * Adds an "Print" button to the bottom or top of a GridField.
@@ -161,7 +162,15 @@ class GridFieldPrintButton extends AbstractGridFieldComponent implements GridFie
             return $dataCols->getDisplayFields($gridField);
         }
 
-        return DataObject::singleton($gridField->getModelClass())->summaryFields();
+        $modelClass = $gridField->getModelClass();
+        $singleton = singleton($modelClass);
+        if (!$singleton->hasMethod('summaryFields')) {
+            throw new LogicException(
+                'Cannot dynamically determine columns. Add a GridFieldDataColumns component to your GridField'
+                . " or implement a summaryFields() method on $modelClass"
+            );
+        }
+        return $singleton->summaryFields();
     }
 
     /**
@@ -226,8 +235,9 @@ class GridFieldPrintButton extends AbstractGridFieldComponent implements GridFie
         /** @var GridFieldDataColumns $gridFieldColumnsComponent */
         $gridFieldColumnsComponent = $gridField->getConfig()->getComponentByType(GridFieldDataColumns::class);
 
-        /** @var DataObject $item */
+        /** @var ViewableData $item */
         foreach ($items->limit(null) as $item) {
+            // Assume item can be viewed if canView() isn't implemented
             if (!$item->hasMethod('canView') || $item->canView()) {
                 $itemRow = new ArrayList();
 
diff --git a/src/Forms/GridField/GridFieldSortableHeader.php b/src/Forms/GridField/GridFieldSortableHeader.php
index 28cd0665f..1320bbc4c 100644
--- a/src/Forms/GridField/GridFieldSortableHeader.php
+++ b/src/Forms/GridField/GridFieldSortableHeader.php
@@ -11,6 +11,7 @@ use SilverStripe\ORM\DataObject;
 use SilverStripe\View\ArrayData;
 use SilverStripe\View\SSViewer;
 use LogicException;
+use SilverStripe\Core\ClassInfo;
 use SilverStripe\Core\Injector\Injector;
 use SilverStripe\Dev\Deprecation;
 
@@ -154,7 +155,7 @@ class GridFieldSortableHeader extends AbstractGridFieldComponent implements Grid
                     if ($tmpItem instanceof SS_List) {
                         // It's impossible to sort on a HasManyList/ManyManyList
                         break;
-                    } elseif ($tmpItem && method_exists($tmpItem, 'hasMethod') && $tmpItem->hasMethod($methodName)) {
+                    } elseif ($tmpItem && ClassInfo::hasMethod($tmpItem, $methodName)) {
                         // The part is a relation name, so get the object/list from it
                         $tmpItem = $tmpItem->$methodName();
                     } elseif ($tmpItem instanceof DataObject
diff --git a/src/Forms/GridField/GridFieldViewButton.php b/src/Forms/GridField/GridFieldViewButton.php
index ea4129eb2..a0efccd6a 100644
--- a/src/Forms/GridField/GridFieldViewButton.php
+++ b/src/Forms/GridField/GridFieldViewButton.php
@@ -62,7 +62,8 @@ class GridFieldViewButton extends AbstractGridFieldComponent implements GridFiel
 
     public function getColumnContent($field, $record, $col)
     {
-        if (!$record->canView()) {
+        // Assume item can be viewed if canView() isn't implemented
+        if ($record->hasMethod('canView') && !$record->canView()) {
             return null;
         }
         $data = new ArrayData([
diff --git a/src/Forms/GridField/GridField_ActionMenuItem.php b/src/Forms/GridField/GridField_ActionMenuItem.php
index 7f22cc15c..d07b23b88 100644
--- a/src/Forms/GridField/GridField_ActionMenuItem.php
+++ b/src/Forms/GridField/GridField_ActionMenuItem.php
@@ -2,7 +2,7 @@
 
 namespace SilverStripe\Forms\GridField;
 
-use SilverStripe\ORM\DataObject;
+use SilverStripe\View\ViewableData;
 
 /**
  * GridField action menu item interface, this provides data so the action
@@ -21,7 +21,7 @@ interface GridField_ActionMenuItem extends GridFieldComponent
      * @see {@link GridField_ActionMenu->getColumnContent()}
      *
      * @param GridField $gridField
-     * @param DataObject $record
+     * @param ViewableData $record
      *
      * @return string $title
      */
@@ -33,7 +33,7 @@ interface GridField_ActionMenuItem extends GridFieldComponent
      * @see {@link GridField_ActionMenu->getColumnContent()}
      *
      * @param GridField $gridField
-     * @param DataObject $record
+     * @param ViewableData $record
      *
      * @return array $data
      */
@@ -46,7 +46,7 @@ interface GridField_ActionMenuItem extends GridFieldComponent
      * @see {@link GridField_ActionMenu->getColumnContent()}
      *
      * @param GridField $gridField
-     * @param DataObject $record
+     * @param ViewableData $record
      *
      * @return string|null $group
      */
diff --git a/src/Forms/GridField/GridField_ActionMenuLink.php b/src/Forms/GridField/GridField_ActionMenuLink.php
index d8727c840..77d0fa3f0 100644
--- a/src/Forms/GridField/GridField_ActionMenuLink.php
+++ b/src/Forms/GridField/GridField_ActionMenuLink.php
@@ -2,7 +2,7 @@
 
 namespace SilverStripe\Forms\GridField;
 
-use SilverStripe\ORM\DataObject;
+use SilverStripe\View\ViewableData;
 
 /**
  * Allows GridField_ActionMenuItem to act as a link
@@ -15,7 +15,7 @@ interface GridField_ActionMenuLink extends GridField_ActionMenuItem
      * @see {@link GridField_ActionMenu->getColumnContent()}
      *
      * @param GridField $gridField
-     * @param DataObject $record
+     * @param ViewableData $record
      *
      * @return string $url
      */
diff --git a/src/Forms/GridField/GridField_ColumnProvider.php b/src/Forms/GridField/GridField_ColumnProvider.php
index 5863560f7..ee900ea40 100644
--- a/src/Forms/GridField/GridField_ColumnProvider.php
+++ b/src/Forms/GridField/GridField_ColumnProvider.php
@@ -34,7 +34,7 @@ interface GridField_ColumnProvider extends GridFieldComponent
      * HTML for the column, content of the <td> element.
      *
      * @param  GridField $gridField
-     * @param  DataObject $record - Record displayed in this row
+     * @param  ViewableData $record - Record displayed in this row
      * @param  string $columnName
      * @return string - HTML for the column. Return NULL to skip.
      */
@@ -44,7 +44,7 @@ interface GridField_ColumnProvider extends GridFieldComponent
      * Attributes for the element containing the content returned by {@link getColumnContent()}.
      *
      * @param  GridField $gridField
-     * @param  DataObject $record displayed in this row
+     * @param  ViewableData $record displayed in this row
      * @param  string $columnName
      * @return array
      */
diff --git a/src/Forms/GridField/GridField_SaveHandler.php b/src/Forms/GridField/GridField_SaveHandler.php
index ece1a5091..f56242615 100644
--- a/src/Forms/GridField/GridField_SaveHandler.php
+++ b/src/Forms/GridField/GridField_SaveHandler.php
@@ -3,6 +3,7 @@
 namespace SilverStripe\Forms\GridField;
 
 use SilverStripe\ORM\DataObjectInterface;
+use SilverStripe\View\ViewableData;
 
 /**
  * A component which is used to handle when a {@link GridField} is saved into
@@ -15,7 +16,7 @@ interface GridField_SaveHandler extends GridFieldComponent
      * Called when a grid field is saved - i.e. the form is submitted.
      *
      * @param GridField $grid
-     * @param DataObjectInterface $record
+     * @param DataObjectInterface&ViewableData $record
      */
     public function handleSave(GridField $grid, DataObjectInterface $record);
 }
diff --git a/src/ORM/Search/SearchContext.php b/src/ORM/Search/SearchContext.php
index d41e26042..54d44cd16 100644
--- a/src/ORM/Search/SearchContext.php
+++ b/src/ORM/Search/SearchContext.php
@@ -105,7 +105,7 @@ class SearchContext
      */
     public function getSearchFields()
     {
-        if ($this->fields->exists()) {
+        if ($this->fields?->exists()) {
             return $this->fields;
         }
 
@@ -443,7 +443,7 @@ class SearchContext
      */
     public function addField($field)
     {
-        $this->fields->push($field);
+        $this->fields?->push($field);
     }
 
     /**
@@ -453,7 +453,7 @@ class SearchContext
      */
     public function removeFieldByName($fieldName)
     {
-        $this->fields->removeByName($fieldName);
+        $this->fields?->removeByName($fieldName);
     }
 
     /**
@@ -500,7 +500,7 @@ class SearchContext
                 continue;
             }
 
-            $field = $this->fields->fieldByName($filter->getFullName());
+            $field = $this->fields?->fieldByName($filter->getFullName());
             if (!$field) {
                 continue;
             }