FIX Make child responsible for its own nested gridfield

[GuySartorelli]

Currently the parent is responsible for dictating how the child's nested gridfield should be configured. This change allows the child to determine that for themselves.

Code before this PR to get nested gridfields

<?php

namespace SilverStripe\FrameworkTest\Fields\NestedGridField;

use SilverStripe\Forms\GridField\GridFieldConfig;
use SilverStripe\Forms\GridField\GridFieldConfig_RecordEditor;
use SilverStripe\ORM\DataObject;
use Symbiote\GridFieldExtensions\GridFieldNestedForm;

class NestedGridFieldParentModel extends DataObject
{
    private static $table_name = 'NestedGridFieldParentModel';

    private static $db = [
        'Title' => 'Varchar(50)',
    ];

    private static $has_many = [
        'Children' => NestedGridFieldChildModel::class,
    ];

    public function getNestedConfig(): GridFieldConfig
    {
        $config = new GridFieldConfig_RecordEditor();
        $config->addComponent(GridFieldNestedForm::create()->setRelationName('GrandChildren'));
        return $config;
    }
}

<?php

namespace SilverStripe\FrameworkTest\Fields\NestedGridField;

use SilverStripe\ORM\DataObject;

class NestedGridFieldChildModel extends DataObject
{
    private static $table_name = 'NestedGridFieldChildModel';

    private static $db = [
        'Title' => 'Varchar(50)',
    ];

    private static $has_one = [
        'Parent' => NestedGridFieldParentModel::class,
    ];

    private static $has_many = [
        'GrandChildren' => NestedGridFieldGrandChildModel::class,
    ];
}

Code after this PR to get nested gridfields

<?php

namespace SilverStripe\FrameworkTest\Fields\NestedGridField;

use SilverStripe\ORM\DataObject;

class NestedGridFieldParentModel extends DataObject
{
    private static $table_name = 'NestedGridFieldParentModel';

    private static $db = [
        'Title' => 'Varchar(50)',
    ];

    private static $has_many = [
        'Children' => NestedGridFieldChildModel::class,
    ];
}

<?php

namespace SilverStripe\FrameworkTest\Fields\NestedGridField;

use SilverStripe\Forms\GridField\GridFieldConfig;
use SilverStripe\Forms\GridField\GridFieldConfig_RecordEditor;
use SilverStripe\ORM\DataObject;
use Symbiote\GridFieldExtensions\GridFieldNestedForm;

class NestedGridFieldChildModel extends DataObject
{
    private static $table_name = 'NestedGridFieldChildModel';

    private static $db = [
        'Title' => 'Varchar(50)',
    ];

    private static $has_one = [
        'Parent' => NestedGridFieldParentModel::class,
    ];

    private static $has_many = [
        'GrandChildren' => NestedGridFieldGrandChildModel::class,
    ];

    public function getNestedConfig(): GridFieldConfig
    {
        $config = new GridFieldConfig_RecordEditor();
        $config->addComponent(GridFieldNestedForm::create()->setRelationName('GrandChildren'));
        return $config;
    }
}

Other change made

This also passes in some information to the getNestedConfig() method which can be used to decide how to display itself. For example, a class which has the Hierarchy extension might want to always list itself as a nested child, but doesn't want to override the default code for that. It could be implemented like so:

<?php

namespace SilverStripe\FrameworkTest\Fields\NestedGridField;

use SilverStripe\Forms\GridField\GridFieldConfig;
use SilverStripe\Forms\GridField\GridFieldConfig_RecordEditor;
use SilverStripe\ORM\DataObject;
use SilverStripe\ORM\Hierarchy\Hierarchy;
use Symbiote\GridFieldExtensions\GridFieldNestedForm;

class NestedGridFieldGrandChildModel extends DataObject
{
    private static $table_name = 'NestedGridFieldGrandChildModel';

    private static $db = [
        'Title' => 'Varchar(50)',
        'Category'=>'Varchar(255)',
        'Tag'=>'Varchar(255)',
    ];

    private static $has_one = [
        'ChildParent' => NestedGridFieldChildModel::class,
    ];

    private static $extensions = [
        Hierarchy::class,
    ];

    public function getNestedConfig(string $parentClass, string $asRelation): ?GridFieldConfig
    {
        // Don't override default hierarchy nested gridfield
        if (is_a($parentClass, NestedGridFieldGrandChildModel::class) && $asRelation === 'Children') {
            return null;
        }
        // Provide nested gridfield to start showing hierarchy
        $config = new GridFieldConfig_RecordEditor();
        $config->addComponent(GridFieldNestedForm::create()->setRelationName('Children'));
        return $config;
    }
}

Issue

• getNestedConfig() called on the parent but should be called on the child #394

[sabina-talipova]

LGTM. Test locally. Works perfect.