Misleading exception when using the Relation FormWidget with an unsupported relation type

[RomainMazB]

Winter CMS Build

dev-develop

PHP Version

7.4

Database engine

No database

Plugins installed

No response

Issue description

When using the Relation formwidget with an unsupported relationship (example detailed below), the formwidget is throwing this misleading Exception:

Steps to replicate

Create a polymorphic One To Many relationship:

class Comment extends Model
{
    public $morphTo = [
        'commentable' => []
    ];
}

class Post extends Model
{
    public $morphMany = [
        'comments' => ['Acme\Blog\Models\Comment', 'name' => 'commentable']
    ];
}

class Product extends Model
{
    public $morphMany = [
        'comments' => ['Acme\Blog\Models\Comment', 'name' => 'commentable']
    ];
}

and then use the commentable relationship inside a relation formwidget of the Comment form.

Workaround

No response

Any further details?

No response