src/Extensions/GridFieldBetterButtonsItemRequest.php
public function recordIsDeletedFromStage()
    {
        // for SiteTree records
        if ($this->owner->hasMethod('getIsDeletedFromStage')) {
            return $this->owner->IsDeletedFromStage;
        }

        if (!$this->owner->record->checkVersioned()) {
            return false;
        }

        if (!$this->owner->record->isInDB()) {
            return true;
        }

        $class = $this->owner->record->class;

        $stageVersion = Versioned::get_versionnumber_by_stage($class, 'Stage', $this->owner->record->ID);

        // Return true for both completely deleted pages and for pages just deleted from stage
        return !($stageVersion);
    }
public function recordIsDeletedFromStage()
    {
        // for SiteTree records
        if ($this->owner->hasMethod('getIsDeletedFromStage')) {
            return $this->owner->IsDeletedFromStage;
        }

        if (!$this->owner->record->checkVersioned()) {
            return false;
        }

        if (!$this->owner->record->isInDB()) {
            return true;
        }

        $class = $this->owner->record->class;

        $stageVersion = Versioned::get_versionnumber_by_stage($class, 'Stage', $this->owner->record->ID);

        // Return true for both completely deleted pages and for pages just deleted from stage
        return !($stageVersion);
    }
Determines if the current record is deleted from stage
@return boolean