Django Admin Actions with Empty QuerySets

You've raised a valid concern about Django's admin actions and their inability to run on empty QuerySets. Based on the Django 5.1 documentation, this limitation still exists in the current implementation of admin actions.

Current Behavior

Django admin actions are designed to operate on selected objects from the change list page. The workflow assumes you'll always have at least one object selected before applying an action. This is why your third use case (importing when no objects are selected) isn't directly supported.

Workaround Solution

For your specific use case, the best approach would be to use the "intermediate pages" pattern described in the documentation. Here's how you could implement it:

PYTHONCopied
from django.contrib import admin
from django.http import HttpResponseRedirect
from django.contrib import messages

@admin.action(description="Import project from partner JSON")
def import_from_partner_json(modeladmin, request, queryset):
    selected_count = queryset.count()
    
    if selected_count > 1:
        # Case 1: Too many objects selected
        messages.error(request, "You can only import to one project at a time.")
        return None
    
    # For both the "one object" and "no objects" cases, redirect to a custom view
    # that will handle the import logic
    return HttpResponseRedirect(
        "/admin/import-project/?count=%s&ids=%s" 
        % (
            selected_count,
            ",".join(str(obj.pk) for obj in queryset)
        )
    )

Then create a custom view that handles both cases:

PYTHONCopied
from django.views.generic import FormView
from django.contrib.admin.views.decorators import staff_member_required
from django.utils.decorators import method_decorator

@method_decorator(staff_member_required, name='dispatch')
class ImportProjectView(FormView):
    template_name = 'admin/import_project.html'
    form_class = ImportProjectForm
    
    def get_initial(self):
        initial = super().get_initial()
        count = int(self.request.GET.get('count', 0))
        if count == 1:
            # One object selected - we're updating
            ids = self.request.GET.get('ids', '').split(',')
            initial['project_id'] = ids[0]
            initial['is_update'] = True
        else:
            # No objects selected - we're creating new
            initial['is_update'] = False
        return initial
    
    def form_valid(self, form):
        # Handle the import logic here
        # ...
        return super().form_valid(form)

Why Django Doesn't Support Empty QuerySets for Actions

The Django team's perspective (as referenced in ticket #10768) seems to be that:

1. Actions are conceptually designed to operate on selected objects
2. Running an action on no selection could lead to unexpected behavior
3. The UI pattern would be confusing to users

However, your use case demonstrates that there are legitimate scenarios where actions that can run on empty QuerySets would be useful.

Alternative Approaches

1. Custom Admin Views: Create a separate button/link in your admin that leads to your import functionality, completely separate from the actions dropdown.

2. Custom Admin Template: Override the admin changelist template to add your own UI element for the "import new" case.

3. Feature Request: Consider submitting a new feature request to Django with your specific use case, suggesting the no_selection_actions attribute or decorator approach you mentioned.

While not ideal, the intermediate pages approach is the most straightforward way to handle your requirements within the current Django admin framework.