[New-bugs-announce] [issue16636] codecs: readline() followed by readlines() returns trunkated results

[Laurynas Speicys]

New submission from Laurynas Speicys:

codecs.readlines() does not read to the end of the file if called after codecs.readline().  

Skimmed through tasks containing codecs in title and could not find a candidate that sounded identical.

Repro follows:

$ cat sample_text.txt
Subject: Incorrect email address
 
RATER EMAIL rejected an invitation from SUBJECT NAME <SUBJECT EMAIL> in
the PROJECT TITLE project.  Notification was sent to <RECIPIENT EMAIL>,
but the email address was no longer valid.


$ python
Python 2.7.3 (default, Sep 26 2012, 21:53:58) 
[GCC 4.7.2] on linux2
>>>
>>> import codecs
>>>
>>> # No problem if readlines() are run at the beginning:
>>>
>>> f_in = codecs.open('sample_text.txt', 'rb', 'utf-8')
>>> f_in.readlines()
[u'Subject: Incorrect email address\n', u'\n', u'RATER EMAIL rejected an invitation from SUBJECT NAME <SUBJECT EMAIL> in\n', u'the PROJECT TITLE project.  Notification was sent to <RECIPIENT EMAIL>,\n', u'but the email address was no longer valid.']
>>> f_in.close()
>>>
>>> # Let us try to read the first line separately,
>>> # and then read the remainder of the file:
>>>
>>> f_in = codecs.open('sample_text.txt', 'rb', 'utf-8')
>>> f_in.readline()
u'Subject: Incorrect email address\n'
>>> f_in.readlines()
[u'\n', u'RATER EMAIL rejected an invitation fro']

The first readlines() does not read to the end. Subsequent readlines() returns what's left to read.

sample_text.txt attached.

----------
files: sample_text.txt
messages: 177098
nosy: laurynas
priority: normal
severity: normal
status: open
title: codecs: readline() followed by readlines() returns trunkated results
type: behavior
versions: Python 2.7
Added file: http://bugs.python.org/file28242/sample_text.txt

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue16636>
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