Can't replace global admin actions with specialized ones per-admin

[Aarni Koskela]

f9ff1df1daac8ae1fc22b27f48735148cb5488dd landed in 2.2 (discussion in #29917), which makes it impossible to replace a generic site-wide action (such as the built-in delete_selected) with a new one. It fails with the admin.E130 system check error.

We're seeing this with the qsessions app, which has to delete its session objects in non-bulk mode in order to clear caches: ​https://github.com/QueraTeam/django-qsessions/blob/c21d602a50c4746da7f698a8d39317ef214e7d05/qsessions/admin.py#L41-L46
(For this particular use case, it seems a fix is to instead override modeladmin.delete_queryset within qsessions's SessionAdmin, as that's what the built-in delete_selected action does per ​https://github.com/django/django/blob/851d9eac23e08ff10a2d6fe5368b02798761663c/django/contrib/admin/actions.py#L40 .)

[Carlton Gibson]

This is ​documented as a backwards incompatible change in the 2.2 release notes.

See the discussion on #29917 and ​the mailing list thread.

See ​Making actions available site-wide docs for the suggested approach.

[Aarni Koskela]

Thanks! I did read the release notes, but the section linked has no mention of global admin actions and it doesn't exactly apply, see below. (Reopening for that reason.)

This issue only arises when

• a global action, say expect_inquisition (or the built-in default delete_selected) has been defined, which is implicitly on every single ModelAdmin
• that global action is still enabled
• and you attempt to explicitly add an action with the same __name__ on any given ModelAdmin class

[Carlton Gibson]

Right, OK, gotcha.

Multiple defined actions with the same name are not supported. The system check added in #29711 led directly to uncovering #29917, which had been latent for many years.

As per the discussion on #29917, and the mailing list thread (that I linked above), the decision was taken to adjust this behaviour.

You need to adjust your code to use site wide actions, or as an alternative you can use subclassing, but now according to Python's normal inheritance rules.

This was an example from the discussion:

class WithCustom(AdminBase):
    actions = AdminBase.actions + ['custom_action']

You're free to adjust actions any way you need (at class definition, in __init__(), in _get_base_actions(), in get_actions()...) See the ​Disabling actions section of the docs. There are plenty of strategies there.

[Carlton Gibson]

Reopening based on mailing list discussion ​https://groups.google.com/d/topic/django-developers/jDz-0wfowqg/discussion

Patch should at least consider whether we'll handle just delete_selected or any action (expect_inquisition say).

(Original triage should have been wontfix rather than invalid looking again.)

[hashlash]

Hi!

May I work on this? I'm kind of new and want to contribute to this community. I've read the discussion mentioned (​https://groups.google.com/d/topic/django-developers/jDz-0wfowqg/discussion) and I think I can implement the solution. Will update as soon as I finish implementing the tests and patches

Cheers

[hashlash]

​https://github.com/django/django/pull/12591

[אורי]

What is delete_selected and how do you use it? What are generic site-wide actions?

[hashlash]

Replying to אורי:

What is delete_selected and how do you use it? What are generic site-wide actions?

delete_selected is a built-in Django's admin action. For more information (including site-wide actions) please read the docs: ​https://docs.djangoproject.com/en/2.2/ref/contrib/admin/actions/

[Mariusz Felisiak <felisiak.mariusz@…>]

In dfbd9ca0:

Fixed #30311 -- Restored ability to override global admin actions.