Protect default collections of site from being deleted or broken in other ways.

[Sebobo]

When an asset collection is defined as default collection for a site, it shouldn't be possible to delete it or do something that breaks that connection.

[Sebobo]

@lorenzulrich please add any idea or information you might have on the topic.

[lorenzulrich]

In a multi-site instance with site-based permissions, you will most likely use AssetCollections as an entry point for assets. The main reasons:

• You can define a default asset collection in the Site configuration that is used for uploaded assets.
• You can use privileges to restrict assets in given asset collections to certain roles.

I see some ways to ensure that the user cannot "lock themselves out" of their own files:

• We could generally prevent deleting asset collections that have still related assets. This could be discussed as a general concept, however you could still get to a state where you can't manage assets - if you don't have any assets at all and delete the collection.
• Any asset collection that is being referenced as defaltAssetCollection from a Site can never be deleted.
• Any asset collection that is referenced by a ReadHierarchicalAssetCollectionPrivilege cannot be deleted. However, since this is based on the title of the asset collection, it can be circumvented quite easily.