Make default Model.__str__() more useful (such as by displaying the primary key)

[Victor Porton]

In [4]: t
Out[4]: <Transaction: Transaction object>

For objects with a PK, it should display instead the value of PK, like this:

Out[4]: <Transaction: pk=7>

If the model has no PK, display like this:

Out[4]: <Transaction: no pk>

[Victor Porton]

I know that this can be done manually with every model, but I want to do it automatically for all models, to reduce code repeating and do it always.

[Aymeric Augustin]

Yes, I agree it would be nice to do *something* about this problem.

In your example, <Transaction: Transaction object> is the repr of the object, and the Transaction object part is the str of the object.

Demo:

>>> class Foo(models.Model):
...     class Meta:
...         app_label = 'admin'
...
>>> Foo()
<Foo: Foo object>
>>> str(Foo())
'Foo object'
>>> repr(Foo())
'<Foo: Foo object>'

So we must think about how __repr__ and __str__ will behave. Having Model.__str__ return pk=... regardless of the model type sounds suboptimal.

[Tim Graham]

Here's a past ​django-developers discussion on the topic. An interested person could revive that thread to try to get a consensus.

[Collin Anderson]

​https://github.com/django/django/pull/8336

(1) is my first choice, pk=1 is my second choice. I'd be fine with either.

[Tim Graham <timograham@…>]

In 7c9cb1ed:

Refs #27953 -- Removed hardcoded uses of Model.str() in tests.

[Tim Graham <timograham@…>]

In 1a49b89:

Fixed #27953 -- Added instance's pk to Model.str().