Many To Many on the same object

[clemblanco]

I can't have a many to many relation working on the same object.

For example I have a Product object. I want this product to be linked to other products so I tried to put:

'RelatedProducts' => 'Product'

in my many_many attribute and then I tried to create a GridField to manage the link between them by using:

$RelatedProductsField = GridField::create(
'RelatedProducts',
'Related Products',
$this->RelatedProducts(),
GridFieldConfig_RelationEditor::create()
);
$fields->addFieldToTab('Root.RelatedProducts', $RelatedProductsField);

But I get the PHP error saying:
Fatal error: Call to a member function stat() on a non-object in /path-to-server/sitename/framework/model/DataObject.php on line 3231

[tractorcow]

Why did you put 'RelatedProduct' => 'Product' and not 'RelatedProducts' => 'Product'?

[clemblanco]

Was a typo my bad. Sorry but it's not the solution.

[wernerkrauss]

is this issue related to #1377 ?

[adrian-stein]

This is still an issue and I am getting the exact same error. Is there any news on when it will be getting fixed?

See this example With related products extending the swipestripe module product class.

<?php
class ProductExtension extends DataExtension{
    private static $many_many = array(
        'RelatedProducts' => 'Product'
    );

    private static $belongs_many_many = array(
        'IsRelatedTo' => 'Product'
    );

    public function updateCMSFields(FieldList $fields) {
        $gridField = GridField::create('RelatedProducts',
            'Related Products',
            $this->owner->RelatedProducts(),
            GridFieldConfig_RelationEditor::create()
        );

        $fields->addFieldToTab('Root.RelatedProducts', $gridField);
    }
}

If I change $this->owner->RelatedProducts() with say CartPage::get() it works fine and the page loads otherwise I get the above error.

[tractorcow]

Fixed with #3799

[adrian-stein]

@tractorcow do you know when is this getting released in a stable version?

[dhensby]

A bit late, @adrian-stein but this is in 3.2.0+