Change the default message in django-admin when deleting

Question

I have a model where a user can add some data and assign this data to a specific month. But if that user had already added some items and try to delete a specific data who is assigned to a previous month it should be locked.

I had success with this, but my problem now is with the message for the user. I would like to remove the default message of the delete button on admin but until now without success.

Here is the image of the problem: MessageImage

admin.py

class MontlyReleaseAdmin(admin.ModelAdmin):
    form = MontlyReleaseForm

    def get_actions(self, request):
        actions = super().get_actions(request)
        if 'delete_selected' in actions:
            del actions['delete_selected']
        return actions


    def delete_model(self, request, obj):
        if not is_valid_date(obj):
            messages.add_message(request, messages.ERROR, 'Not Deleted')
        else:
            super().delete_model(request, obj)

    admin.site.register(MontlyRelease, MontlyReleaseAdmin)

Answer 1

You can override the has_delete_permission(…) method [Django-doc] to prevent deletion:

class MontlyReleaseAdmin(admin.ModelAdmin):
    
    # …
    
    def (self, request, obj=None):
        if not is_valid_date(obj):
            messages.add_message(request, messages.ERROR, 'Not Deleted')
            return False
        return super().has_delete_permission(request, obj)

here you thus do not override the delete_model(…) method itself, but the method that checks if you can delete the object.