file.tell affect decoding

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2016-05-10.03:34:33.687>
labels = ['expert-unicode']
title = 'file.tell affect decoding'
updated_at = <Date 2016-06-21.13:21:28.505>
user = 'https://bugs.python.org/mfmain'

bugs.python.org fields:

activity = <Date 2016-06-21.13:21:28.505>
actor = 'martin.panter'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Unicode']
creation = <Date 2016-05-10.03:34:33.687>
creator = 'mfmain'
dependencies = []
files = []
hgrepos = []
issue_num = 26990
keywords = []
message_count = 2.0
messages = ['265224', '268994']
nosy_count = 4.0
nosy_names = ['vstinner', 'ezio.melotti', 'martin.panter', 'mfmain']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = None
url = 'https://bugs.python.org/issue26990'
versions = ['Python 3.5']