[issue28459] _pyio module broken on Cygwin / setmode not usable

[Irit Katriel]

Change by Irit Katriel :


--
resolution: duplicate -> wont fix

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue28459] _pyio module broken on Cygwin / setmode not usable

[Irit Katriel]

Change by Irit Katriel :


--
resolution:  -> duplicate
stage: patch review -> resolved
status: open -> closed
superseder:  -> Cygwin is unsupported - close all open issues and list them 
here.

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue28459] _pyio module broken on Cygwin / setmode not usable

[Erik Bray]

Change by Erik Bray :


--
pull_requests: +13877
pull_request: https://github.com/python/cpython/pull/14013

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue28459] _pyio module broken on Cygwin / setmode not usable

[Zachary Ware]

Change by Zachary Ware :


--
nosy: +zach.ware
stage:  -> patch review
versions:  -Python 3.5

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue28459] _pyio module broken on Cygwin / setmode not usable

[Erik Bray]

Erik Bray  added the comment:

Right, the current patch is really combining several issues.  I'll make  a PR 
from it that just fixes the _pyio issue.  I'll also open an issue for fixing 
the ctypes bug (this is a patch I've had in my cygwin branch for ages but just 
never got around to making a report for...)

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue28459] _pyio module broken on Cygwin / setmode not usable

[Masayuki Yamamoto]

Masayuki Yamamoto  added the comment:

FYI, cygwin-pyio-setmode.patch includes two extra parts for running on Cygwin.  
First, fix import error for ctypes (unopened issue). Second, fix building 
_ctypes module (#4032 - PR 4153).

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue28459] _pyio module broken on Cygwin / setmode not usable

[Erik Bray]

Erik Bray added the comment:

Hi Masayuki, thanks for the response (I thought I replied to this earlier but 
maybe I only imagined it--I've been on vacation).

I agree with just about everything you write here.

I'm aware of the FreeBSD setmode(), but I figured os.setmode() could do 
different things on different platforms as applicable.  But that would also be 
very confusing.

Your patch using ctypes looks fine to me--I considered doing the same, but what 
I'm not sure is if it's kosher to use ctypes here, given that it's techically 
an optional module.  Since _pyio is, as I understand it, mainly used for 
testing it's probably fine?  But I think we'll need some core maintainers' 
comments here...

Implementing a cygwin module would be really nice, actually, even if it isn't 
included in the stdlib.  There are a few other cygwin-specific APIs that it is 
useful to have wrappers around: 
https://cygwin.com/cygwin-api/cygwin-functions.html  But that would be outside 
the scope of fixing this issue.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue28459] _pyio module broken on Cygwin / setmode not usable

[Masayuki Yamamoto]

Masayuki Yamamoto added the comment:

I agree to use setmode() at _pyio module for Cygwin. However, I have two 
reasons that I disagree to the implementation of os.setmode().
First, FreeBSD has another setmode() that operate file permission bits [1]. 
Therefore the implementation of os.setmode() will be confused to those users.
Second, msvcrt.setmode() isn't used almost in standard library, the function is 
just used by _pyio module and subprocess test. Thus I think there aren't much 
need that implements setmode() to os module.

Easy way for a solution of import error on Cygwin, setmode() is implemented on 
_pyio using ctypes. then Cygwin CPython forget setmode().
Otherwise it's hard way, For avoiding confliction to other platforms, I'd 
propose to create the cygwin module. I thought a solution implementing 
imitation msvcrt module, but it is unreasonable because Cygwin doesn't have 
other Windows API.

I tried written the patch of easy way that implements setmode() into _pyio. 
This patch is included parts to succeed import _pyio.

[1] https://www.freebsd.org/cgi/man.cgi?query=setmode=3

--
components: +Library (Lib)
keywords: +patch
nosy: +masamoto
versions: +Python 3.5, Python 3.6, Python 3.7
Added file: http://bugs.python.org/file45163/cygwin-pyio-setmode.patch

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue28459] _pyio module broken on Cygwin / setmode not usable

[Erik Bray]

New submission from Erik Bray:

Since the patch to #24881 was merged the _pyio module has been non-importable 
on Cygwin, due to an attempt to import from the msvcrt module.

However, the msvcrt module is not built on Cygwin (Cygwin does not use MSVCRT). 
 Cygwin's libc does, however, have _setmode.

The problem this is trying to solve is to call _setmode 
(https://msdn.microsoft.com/en-us/library/tw4k6df8.aspx) on file descriptors to 
ensure that they are O_BINARY instead of O_TEXT (a distinction that needs to 
made on Windows).

Fortunately, on Cygwin, it is fairly rare that a file descriptor will have mode 
O_TEXT, but it it is possible.  See 
https://cygwin.com/faq/faq.html#faq.programming.msvcrt-and-cygwin

This could be tricky to solve though.  Removing setmode() call entirely works 
for me as far as the test suite is concerned.  But it leaves _pyio slightly 
incongruous with the C implementation in this one small aspect, and it *is* a 
bug.

I would propose for Python 3.7 adding an os.setmode() function.  On Windows 
this could be simply an alias for msvcrt.setmode() (or vice-versa).  But 
because setmode() is available also in Cygwin (and technically some other 
platforms too, though none that are currently supported by Python) it would be 
a good candidate for inclusion in the os module I think (for those platforms 
that have it).

--
components: IO
messages: 278802
nosy: erik.bray
priority: normal
severity: normal
status: open
title: _pyio module broken on Cygwin / setmode not usable
type: crash

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com