#30222: documentation bug for base managers
-------------------------------+--------------------------------------
     Reporter:  David Gudeman  |                    Owner:  nobody
         Type:  Bug            |                   Status:  closed
    Component:  Documentation  |                  Version:  2.1
     Severity:  Normal         |               Resolution:  invalid
     Keywords:  base_manager   |             Triage Stage:  Unreviewed
    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:   => invalid


Comment:

 Grrr... Hi David.

 Can I first say, you pretty much want to forget this bit of the docs
 exists — unless you're super sure what you're doing, and even then, leave
 `_base_manager` well alone. (TBH not sure why it's documented the `_`
 prefix implies private method... — NoteToSelf: should look up why it's
 documented)

 The key point is that the `.filter(question__name__startswith)` bit, as a
 query, will use `Question._default_manager` even though the
 `choice.question` lookup, as a direct access, will use `_base_manager`.

 Have a read of (some of)
 
[https://github.com/django/django/blob/master/django/db/models/fields/related_descriptors.py
 `django/db/models/fields/related_descriptors.py`] to see where
 `_base_manager` is used in this way. (Imagine you have a foreign key to an
 object filtered by `_default_manager` 💥...)

 I'm not sure this is really addressable. Bar a big warning banner saying
 "Here be dragons" I don't think there's much we can do to clarify this.
 (But concrete suggestions always to be considered...)

-- 
Ticket URL: <https://code.djangoproject.com/ticket/30222#comment:1>
Django <https://code.djangoproject.com/>
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