SimpleLazyObject missing __repr__ proxy

[spinus]

SimpleLazyObject (from django.utils.functionals) does not proxy _repr_ method.
Use Case:

User.__unicode__ -> print data for user, example: "user@email.com"
User.__repr__ -> print debugging data, example: "<User pk:1, email:user@email.com, points:123>"

_unicode_ is used by most of application to render user content so I cant override it to using at logging. _repr_ is used in logging.

Example user message: "Hi %s"%request.user
Example logging message: "%r just logged in"%request.user

When user is wrapped with SimpleLazyObject _repr_ method of User is not called.
My idea is to make it available like

SimpleLazyObject._repr_ = lambda self: '<SimpleLazyObject: %r>'%self._wrapped

Patch:

--- a/django/utils/functional.py
+++ b/django/utils/functional.py
@@ -303,6 +303,9 @@ class SimpleLazyObject(LazyObject):
     def __reduce__(self):
         return (self.__newobj__, (self.__class__,), self.__getstate__())
 
+    def __repr__(self):
+        return '<SimpleLazyObject: %r>' % self._wrapped
+
     # Need to pretend to be the wrapped class, for the sake of objects that care
     # about this (especially in equality tests)
     __class__ = property(new_method_proxy(operator.attrgetter("__class__")))

[Preston Holmes]

Since a lazy object represents itself as the target class - it should try to be that class as much as possible, and not try to be "something special" even though it is.

So __repr__ should just proxy like other magic methods on the class.

Accepting the ticket based on the fact that we should do something explicit for __repr__, but rejecting the wrapped result.

[Preston Holmes]

After some further discussion about the value in debugging the following is now suggested:

Do show in __repr__ that we are a lazy object

check whether the lazy object has been evaluated

if not evaluated, include the repr of the setup function as the wrapped content - so that lazy objects are not evaluated at the time of repr call

otherwise wrap the target instances __repr__ method as proposed.

[fhahn]

implemented repr and updated test

[fhahn]

the Github branch is ​https://github.com/fhahn/django/tree/ticket_19543

[Tomek Paczkowski]

Looks good!

[fhahn]

forgot to link the github pull request: ​https://github.com/django/django/pull/709

[Preston Holmes <preston@…>]

In 0ea5bf88dddd7fbdef7fe8d00162c9753565f5c0:

Fixed #19543 -- implemented SimpleLazyObject.repr

Thanks to Florian Hahn for the patch