[Django] #32549: Make `Q(Q(), ...)` equivalent to `Q(...)`

[Django]

#32549: Make `Q(Q(), ...)` equivalent to `Q(...)`
-------------------------------------+-------------------------------------
               Reporter:  jonathan-  |          Owner:  nobody
  golorry                            |
                   Type:             |         Status:  new
  Cleanup/optimization               |
              Component:  Database   |        Version:  dev
  layer (models, ORM)                |       Keywords:  Q objects, nested,
               Severity:  Normal     |  empty
           Triage Stage:             |      Has patch:  0
  Unreviewed                         |
    Needs documentation:  0          |    Needs tests:  0
Patch needs improvement:  0          |  Easy pickings:  0
                  UI/UX:  0          |
-------------------------------------+-------------------------------------
 Empty Q objects (`Q()` or `~Q()`, etc) evaluate to `False`, but `Q(Q())`
 evaluates to `True`. This interferes with the shortcut on logical
 operations involving empty Q objects and can lead to bugs when trying to
 detect empty operations.
 {{{
 def q_any(iterable):
     q = Q()
     for element in iterable:
         q |= element
     if q:
         return q
     return Q(pk__in=[])
 Item.objects.filter(q_any())  # no items
 Item.objects.filter(q_any([Q()]))  # no items
 Item.objects.filter(q_any([Q(Q())]))  # all items
 }}}

 This patch removes empty Q objects from `args` during Q object
 initialization.

 This requires https://code.djangoproject.com/ticket/32548 in order to
 prevent a regression in logical operations between query expressions and
 empty Q objects.

-- 
Ticket URL: <https://code.djangoproject.com/ticket/32549>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.

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