infinite recursion with setfilesystemencoding and pdb

[ccomb]

BPO	8740
Nosy	@vstinner, @florentx
Superseder	bpo-8226: sys.setfilesystemencoding("xxx"); open("a") => stack overflow

^{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 2010-05-17.15:05:04.849>
created_at = <Date 2010-05-17.13:45:49.452>
labels = ['type-bug']
title = 'infinite recursion with setfilesystemencoding and pdb'
updated_at = <Date 2010-05-19.12:03:22.807>
user = 'https://bugs.python.org/ccomb'

bugs.python.org fields:

activity = <Date 2010-05-19.12:03:22.807>
actor = 'ccomb'
assignee = 'none'
closed = True
closed_date = <Date 2010-05-17.15:05:04.849>
closer = 'flox'
components = ['None']
creation = <Date 2010-05-17.13:45:49.452>
creator = 'ccomb'
dependencies = []
files = []
hgrepos = []
issue_num = 8740
keywords = []
message_count = 7.0
messages = ['105904', '105906', '105910', '105911', '105912', '105913', '106050']
nosy_count = 3.0
nosy_names = ['vstinner', 'flox', 'ccomb']
pr_nums = []
priority = 'normal'
resolution = 'duplicate'
stage = 'resolved'
status = 'closed'
superseder = '8226'
type = 'behavior'
url = 'https://bugs.python.org/issue8740'
versions = ['Python 3.1']

[ccomb]

This leads to a maximum recursion depth error:

$ python3.1
>>> import sys, pdb
>>> sys.setfilesystemencoding('iso8859-7')
>>> pdb.set_trace()

I'm on ubuntu 10.04 x86_64, with LANG=fr_FR.utf8

[florentx]

Next release should fix it: 3.1.3
(Tested on 3.1 branch)

[vstinner]

What is the problem?

$ python3.1
Python 3.1.2 (r312:79147, Apr 21 2010, 23:52:07) 
[GCC 4.4.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys, pdb; sys.setfilesystemencoding('iso8859-7'); pdb.set_trace()
--Return--
> <stdin>(1)<module>()->None
(Pdb) 

Where is the infinite loop?

[vstinner]

The file system encoding should not be modifiable. Call sys.setfilesystemencoding() breaks Python, eg. module filenames are not reencoded. See also bpo-8611.

sys.setfilesystemencoding() is as danregeous as sys.setdefaultencoding() because it changes too much things in Python.

If you would like to decode a filename with an encoding different than sys.setfilesystemencoding(): use the bytes type. Eg. os.listdir(b'.') gives you bytes filenames.

[ccomb]

Traceback (most recent call last):
  File "/usr/lib/python3.1/encodings/__init__.py", line 98, in search_function
    level=0)
  File "/usr/lib/python3.1/encodings/__init__.py", line 98, in search_function
    level=0)
(...)
  File "/usr/lib/python3.1/encodings/__init__.py", line 98, in search_function
    level=0)
  File "/usr/lib/python3.1/encodings/__init__.py", line 98, in search_function
    level=0)
  File "/usr/lib/python3.1/encodings/__init__.py", line 83, in search_function
    norm_encoding = normalize_encoding(encoding)
  File "/usr/lib/python3.1/encodings/__init__.py", line 55, in normalize_encoding
    if isinstance(encoding, bytes):
RuntimeError: maximum recursion depth exceeded while calling a Python object

[vstinner]

Oh, flox closed the issue: it's a duplicate of bpo-8226. The bug was fixed in Python 3.1.2 by myself (r79394).

[ccomb]

(I forgot to mention that the bug occured on python 3.1.2.)