urllib2 maximum recursion depth exceeded

[nako521]

BPO	6500
Nosy	@orsenthil, @ezio-melotti, @berkerpeksag, @serhiy-storchaka
Files	issue6500.diff issue6500_2.patch

^{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 = 'https://github.com/serhiy-storchaka'
closed_at = <Date 2016-01-18.08:59:33.280>
created_at = <Date 2009-07-17.08:26:12.551>
labels = ['type-bug', 'library']
title = 'urllib2 maximum recursion depth exceeded'
updated_at = <Date 2016-01-18.08:59:33.278>
user = 'https://bugs.python.org/nako521'

bugs.python.org fields:

activity = <Date 2016-01-18.08:59:33.278>
actor = 'serhiy.storchaka'
assignee = 'serhiy.storchaka'
closed = True
closed_date = <Date 2016-01-18.08:59:33.280>
closer = 'serhiy.storchaka'
components = ['Library (Lib)']
creation = <Date 2009-07-17.08:26:12.551>
creator = 'nako521'
dependencies = []
files = ['40112', '41510']
hgrepos = []
issue_num = 6500
keywords = ['patch']
message_count = 13.0
messages = ['90612', '90615', '100258', '247916', '257373', '257566', '257569', '257572', '257573', '257575', '258495', '258504', '258506']
nosy_count = 7.0
nosy_names = ['jhylton', 'orsenthil', 'ezio.melotti', 'nako521', 'python-dev', 'berker.peksag', 'serhiy.storchaka']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue6500'
versions = ['Python 2.7']

[nako521]

def __getattr__(self, attr):
        # XXX this is a fallback mechanism to guard against these
        # methods getting called in a non-standard order.  this may be
        # too complicated and/or unnecessary.
        # XXX should the __r_XXX attributes be public?
        if attr[:12] == '_Request__r_':
            name = attr[12:]
            if hasattr(Request, 'get_' + name):
                getattr(self, 'get_' + name)()
                return getattr(self, attr)
        raise AttributeError, attr

this may cause "maximum recursion depth exceeded"

>>> import urllib2
>>> req = urllib2.Request('http://www.nbc.com')
>>> req._Request__r_method
RuntimeError: maximum recursion depth exceeded

"return getattr(self, attr)"? should it be removed?

[ezio-melotti]

That __getattr__ was removed in r70815 and in Python 3.1 it's OK.
The change wasn't backported to the trunk though.

Assigning to Jeremy to see what he thinks about it.

[jhylton]

Ok. I'll take a look, too.

Jeremy

On Sat, Feb 27, 2010 at 4:30 AM, Ezio Melotti <report@bugs.python.org> wrote:

Changes by Ezio Melotti <ezio.melotti@gmail.com>:

----------
nosy: +orsenthil
status: pending -> open

---

Python tracker <report@bugs.python.org>
<http://bugs.python.org/issue6500\>

---

[berkerpeksag]

Here is a patch for 2.7. I don't think backporting 9eceb618274a to 2.7 is worth the effort for this, so I just fixed the __getattr__ method and added a test.

[berkerpeksag]

Thank you Ezio, I'll commit this tomorrow.

[python-dev]

New changeset fbea8ff8db5e by Berker Peksag in branch '2.7':
Issue bpo-6500: Fix "maximum recursion depth exceeded" error caused by Request.__getattr__()
https://hg.python.org/cpython/rev/fbea8ff8db5e

[orsenthil]

Hi @berker,

This patch breaks the unit tests. Could you confirm (or reject) this?
Thanks

[python-dev]

New changeset e2faa18802bb by Berker Peksag in branch '2.7':
Issue bpo-6500: Reverting fbea8ff8db5e since it broke tests
https://hg.python.org/cpython/rev/e2faa18802bb

[berkerpeksag]

Thanks, Senthil. I've just reverted fbea8ff8db5e. Sorry for the noise!

[serhiy-storchaka]

__getattr__() was purposed to handle two lazily created private attributes: __r_type and __r_host. They are set in corresponding get_-methods.

Here is a patch that makes __getattr__() to handle only these attributes.

[orsenthil]

@serhiy, the patch looks good to me. This change is an excellent idea. Please commit it.

[python-dev]

New changeset d34fdd1736f2 by Serhiy Storchaka in branch '2.7':
Issue bpo-6500: Fixed infinite recursion in urllib2.Request.__getattr__().
https://hg.python.org/cpython/rev/d34fdd1736f2

[serhiy-storchaka]

Thank you for the review Senthil.