Create an abstract model named BaseAttachment that can be overwritten

[vieirafrancisco]

Hi,

I felt the need of an abstract class of Attachment to overwrite the basic fields without creating two tables in the database.
Thought in something like that, having BaseAttachment without the "creator" field and assign it to the original model Attachment that overwrites the BaseAttachment model class.

I would like your opinion about this code.
thanks :)

[atodorov]

Overall looks good to me but I have 2 comments here:

1. Needs rebase on top of latest in order to trigger tests

2. Everything that uses the Attachment class will not work with your overriden/custom class that will inherit from BaseAttachment. At the very minimum I see: delete_stale_attachments.py, attachments_tags.py, admin.py, forms.py (used in views).

This second item pretty much breaks the entire out-of-the box experience of django-attachments because all of these places contain hard-coded references to the Attachment model itself instead of whatever custom model the developer provides in their app.

So IMO this can go in either of 2 directions:

1. If you are building a custom app and care only about the model and not really anything else (iow you are handling all of the above mentioned functionality yourself) inheriting directly from Attachment and having another DB table should not be a big deal IMO.

2. If you are aiming to provide a fully customizable experience for the developer this PR needs more work (could be split into smaller PRs which are easier to review). Something like:

• add a setting and remove hard-coded references; possibly refactor tests a bit so they consume the setting. Similar to what Django does for the User model.
• add the abstract BaseAttachment class
• document the changes and how others can use them
• add a custom attachment model class in the test suite and retest everything with it as well (could be a parameter to avoid code duplication).
• fix any bugs if present