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