#22296: m2m_changed pk_set value inconsistent between post_add and post_remove
-------------------------------------+-------------------------------------
     Reporter:  anentropic           |                    Owner:  nobody
         Type:  Bug                  |                   Status:  closed
    Component:  Database layer       |                  Version:  1.5
  (models, ORM)                      |
     Severity:  Normal               |               Resolution:  duplicate
     Keywords:                       |             Triage Stage:  Accepted
    Has patch:  0                    |      Needs documentation:  0
  Needs tests:  0                    |  Patch needs improvement:  0
Easy pickings:  0                    |                    UI/UX:  0
-------------------------------------+-------------------------------------
Changes (by Carlton Gibson):

 * status:  new => closed
 * resolution:   => duplicate


Comment:

 As per #29615, the behaviour here is now different.

 * For `add()`, multiple calls with the same ids now only result in a
 single signal being dispatched.
 * For `delete()`, the signal is dispatched each time.

 See [https://code.djangoproject.com/ticket/29615#comment:2 comment on
 #29615] for more detail but, the underlying difference is that `add()`
 calls filter duplicates to avoid `IntegrityError` when inserting the
 records. There's no need for this with delete.

 Happy for others to comment differently but, I thought on #29615 that the
 extra DB query would not be worth it to eliminate the extra signal, but
 that the anomaly could be documented.

 Given all that I'll close this as a duplicate (despite it being the older
 ticket, and my having previous thought them not duplicates... sigh...).
 Further discussion on #29615 please.

-- 
Ticket URL: <https://code.djangoproject.com/ticket/22296#comment:3>
Django <https://code.djangoproject.com/>
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