type() and isinstance() do not call __getattribute__

[pervognsen]

BPO	1263635
Nosy	@birkenfeld, @rhettinger

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2006-02-20.22:10:05.000>
created_at = <Date 2005-08-19.02:07:29.000>
labels = ['interpreter-core']
title = 'type() and isinstance() do not call __getattribute__'
updated_at = <Date 2006-02-20.22:10:05.000>
user = 'https://bugs.python.org/pervognsen'

bugs.python.org fields:

activity = <Date 2006-02-20.22:10:05.000>
actor = 'georg.brandl'
assignee = 'none'
closed = True
closed_date = None
closer = None
components = ['Interpreter Core']
creation = <Date 2005-08-19.02:07:29.000>
creator = 'pervognsen'
dependencies = []
files = []
hgrepos = []
issue_num = 1263635
keywords = []
message_count = 3.0
messages = ['26080', '26081', '26082']
nosy_count = 3.0
nosy_names = ['georg.brandl', 'rhettinger', 'pervognsen']
pr_nums = []
priority = 'normal'
resolution = 'wont fix'
stage = None
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue1263635'
versions = ['Python 2.4']

[pervognsen]

The built-in functions type() and isinstance() do not call
__getattribute__ for instances of user-defined classes.
Thus, for instance,

x.__class__ == sometype

and

type(x) == sometype

can give inconsistent results.

I ran into this problem in writing a transparent
persistence system, where instances of proxy classes
are used as stand-ins for unloaded objects and the
proxy does just-in-time loading by overloading
__getattribute__ and __setattr__ (which changes
__class__).

(This applies to 2.4.1.)

[rhettinger]

Logged In: YES
user_id=80475

I don't think this is going to change. A number of builtins
directly access an object's structure and do not respect
overrides via __getattribute__. This is somewhat intrinsic
the Python's current design.

[birkenfeld]

Logged In: YES
user_id=849994

Closing as I feel Raymond's right.