Opened 8 years ago

Closed 8 years ago

#18538 closed Bug (wontfix)

type(SimpleLazyObject) returns SimpleLazyObject rather than type(_wrapped)

Reported by: Jeremy Dunck Owned by: nobody
Component: Database layer (models, ORM) Version: 1.4
Severity: Normal Keywords:
Cc: Triage Stage: Unreviewed
Has patch: no Needs documentation: no
Needs tests: no Patch needs improvement: no
Easy pickings: no UI/UX: no

Description (last modified by Jeremy Dunck)

In 1.4 we introduced request.user as a SimpleLazyObject. This has caused some bugs caused by abstraction leakage.

Today we ran across another - I'm expecting Router.allow_relation to be called with model instances ( and using type() to get to the Model subclass.

type(obj1)._meta fails because type(obj1) returns SimpleLazyObject.

I've worked around by calling obj1.class (which is specifically proxied), but I'm noting the leakage here. I think there's nothing to be done (type is implemented in C (PyObject_Type) and reaches into the python object structure) but I am noting in here in case someone else has a bright idea for fixing it.

At least this ticket can serve as a workaround to others coming across this surprise. :)

Tough call on "component", could be ORM (since router in this case) or .auth (since that's what's Lazy'd).

Change History (3)

comment:1 Changed 8 years ago by Jeremy Dunck

Description: modified (diff)

comment:2 Changed 8 years ago by Jeremy Dunck

Description: modified (diff)

comment:3 Changed 8 years ago by Luke Plant

Resolution: wontfix
Status: newclosed

I also suspect there is nothing that can be done. Other approaches to making request.user lazy:

  1. Dynamically add something to the request class e.g. a user property. This causes problems with tests because you are mutating global state - we tried this before, and changed to SimpleLazyObject because of this problem.
  2. Using lazy - doesn't work because you don't know the type of user. It could be a third party class returned by a custom authentication backend.

So I'm going to resolve as WONTFIX for now, but anyone with bright ideas for fixing this is welcome to re-open.

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