Value of NOT_PROVIDED might collide with real data

[Antti Kaihola]

In django.core.meta.fields, NOT_PROVIDED is defined as

# Random entropy string used by "default" param.
NOT_PROVIDED = 'oijpwojefiojpanv'

Although extremely unlikely, this string could appear as a default value in a model and be interpreted as if no default value was provided.

Is there something preventing the following:

class NOT_PROVIDED:
    pass

Or are there some control characters in the range chr(0..31) which don't make sense in the database backend side and could be used here?

[akaihola <antti.kaihola@…>]

Or what about this solution:

class NotProvided(str):
    pass

NOT_PROVIDED = NotProvided('No default value is provided.')

if some_default_value is NOT_PROVIDED:
   print 'There is no default value.'
   # and act accordingly

[Adrian Holovaty]

(In [2454]) Fixed #1213 -- Changed value of NOT_PROVIDED so that it's not a string, to prevent possible (but highly unlikely) collisions. Thanks, akaihola