python2 file __repr__ does not escape filename

[RonnyPfannschmidt]

BPO	14161
Nosy	@pitrou, @pjenvey, @ezio-melotti, @merwok, @RonnyPfannschmidt
Files	issue14161.diff: Patch against 2.7.

^{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/ezio-melotti'
closed_at = <Date 2012-10-01.01:38:27.506>
created_at = <Date 2012-02-29.16:43:29.986>
labels = ['interpreter-core', 'type-bug']
title = 'python2 file __repr__ does not escape filename'
updated_at = <Date 2012-10-02.17:10:08.198>
user = 'https://github.com/RonnyPfannschmidt'

bugs.python.org fields:

activity = <Date 2012-10-02.17:10:08.198>
actor = 'Ronny.Pfannschmidt'
assignee = 'ezio.melotti'
closed = True
closed_date = <Date 2012-10-01.01:38:27.506>
closer = 'ezio.melotti'
components = ['Interpreter Core']
creation = <Date 2012-02-29.16:43:29.986>
creator = 'Ronny.Pfannschmidt'
dependencies = []
files = ['24694']
hgrepos = []
issue_num = 14161
keywords = ['patch']
message_count = 12.0
messages = ['154649', '154674', '154675', '154679', '154702', '154810', '155418', '155420', '155422', '171688', '171817', '171818']
nosy_count = 6.0
nosy_names = ['pitrou', 'pjenvey', 'ezio.melotti', 'eric.araujo', 'python-dev', 'Ronny.Pfannschmidt']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue14161'
versions = ['Python 2.7']

[RonnyPfannschmidt]

behaviour:
>>> name = 'woo\raa'
>>> open(name, 'w')
aa', mode 'w' at 0x295a8a0>

expected:
>>> name = 'woo\raa'
>>> open(name, 'w')
<open file 'woo\raa', mode 'w' at 0x295a8a0>

note:
don't ask why i tried this chunk of code in the first place

[merwok]

Funny one :D Reproduced on linux:

  >>> open('/tmp/t\nest', 'w')
  <open file '/tmp/t
  est', mode 'w' at 0x7f11268a19c0>

file_repr in Objects/fileobject.c calls http://docs.python.org/c-api/unicode#PyUnicode_AsUnicodeEscapeString, equivalent to encode('unicode-escape'), so backslashes should be escaped.

[merwok]

Duh, obviously that code branch is used only for unicode paths:

  >>> open('/tmp/t\nest', 'w')
  <open file '/tmp/t
  est', mode 'w' at 0x7f6f0f3dd9c0>
  >>> open(u'/tmp/t\nest', 'w')
  <open file u'/tmp/t\nest', mode 'w' at 0x7f6f0f3dda50>

There does not seem to be something similar in http://docs.python.org/c-api/string, so I guess one would have to create intermediary objects to decode str to unicode, transform with unicode-escape and convert back to str.

[ezio-melotti]

The attached patch seems to do the trick (not sure if it's the best way to fix the issue though):
>>> open('woo\raa')
<open file 'woo\raa', mode 'r' at 0xb77c2aa8>
>>> open('woo\ra\'a', 'w')
<open file "woo\ra'a", mode 'w' at 0xb77c2b88>
>>> open('woo\ra\'a"', 'w')
<open file 'woo\ra\'a"', mode 'w' at 0xb77c2b18>
>>> 

It's more or less equivalent to:

• return "<open file '%s', mode '%s' at %p>" % (fname, mode, addr)
  + return "<open file %s, mode '%s' at %p>" % (repr(fname), mode, addr)

[pitrou]

1. PyObject_Repr() should IMO be preferred (it's the abstract, high-level function).
2. You must check the result for NULL before calling PyString_AsString() on it.

[pjenvey]

I think you want to decref the result of PyObject_Repr after the fact, too

[python-dev]

New changeset 6c1964dee98b by Ezio Melotti in branch '2.7':
bpo-14161: fix the __repr__ of file objects to escape the file name.
http://hg.python.org/cpython/rev/6c1964dee98b

[python-dev]

New changeset 86c749151660 by Ezio Melotti in branch '2.7':
bpo-14161: fix compile error under Windows.
http://hg.python.org/cpython/rev/86c749151660

[python-dev]

New changeset 6b1fad34d893 by Ezio Melotti in branch '2.7':
bpo-14161: fix test failures on Windows.
http://hg.python.org/cpython/rev/6b1fad34d893

[ezio-melotti]

Not sure why this is still open -- probably I was just waiting for the buildbots and forgot it open. The issue seems fixed, so I'm going to close it now.

[RonnyPfannschmidt]

wtf? you made it possible to return NULL in some case

[RonnyPfannschmidt]

sorry for the buzz, i got myself up to date on the c api now

why is there still the unicode case?
the PyObject_Repr variant should work fine in both cases