msvcrt could not be imported

[petrikas]

BPO	23995
Nosy	@tjguk, @bitdancer, @zware, @eryksun, @zooba

^{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/zooba'
closed_at = <Date 2015-05-14.11:06:55.852>
created_at = <Date 2015-04-18.18:45:16.087>
labels = ['library', 'OS-windows', 'type-crash', 'release-blocker']
title = 'msvcrt could not be imported'
updated_at = <Date 2015-05-14.23:05:33.389>
user = 'https://bugs.python.org/petrikas'

bugs.python.org fields:

activity = <Date 2015-05-14.23:05:33.389>
actor = 'eryksun'
assignee = 'steve.dower'
closed = True
closed_date = <Date 2015-05-14.11:06:55.852>
closer = 'r.david.murray'
components = ['Library (Lib)', 'Windows']
creation = <Date 2015-04-18.18:45:16.087>
creator = 'petrikas'
dependencies = []
files = []
hgrepos = []
issue_num = 23995
keywords = []
message_count = 15.0
messages = ['241438', '241439', '241449', '241453', '241456', '243098', '243099', '243143', '243144', '243145', '243146', '243150', '243174', '243192', '243229']
nosy_count = 9.0
nosy_names = ['tim.golden', 'r.david.murray', 'BreamoreBoy', 'python-dev', 'zach.ware', 'eryksun', 'steve.dower', 'petrikas', 'Kain']
pr_nums = []
priority = 'release blocker'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'crash'
url = 'https://bugs.python.org/issue23995'
versions = ['Python 3.5']

[petrikas]

Python cannot access msvcrt's putwch() when using manage.py syncdb

To reproduce:

1. Call manage.py syncdb and try to create a new superuser
2. It crashes after inputting email (or before asking for the password)

Reproducible with 3.5a3, seems to be a regression from 3.4.3. Downgrading fixed the issue

[petrikas]

Edit: I am using a windows 8.1 system and django 1.8

[bitdancer]

Can you reproduce this without involving Django? That would make it more likely that someone will have time to take a look at it.

[eryksun]

The new CRT used by 3.5 has a separate header, corecrt_wconio.h, for declarations shared by conio.h and wchar.h. Thus the _WCONIO_DEFINED macro is no longer defined, and consequently PC/msvcrtmodule.c skips defining getwch, getwche, putwch, and ungetwch.

I guess this check was added to support DOS-based Windows 9x. NT-based Windows would always support wide-character console I/O.

[zooba]

You're right, we should be able to remove the ifdef for these (or hide them behind MS_WINDOWS if necessary).

[Kain]

Had the same problem but was able to fix this by rewriting the win_getpass method in getpass.py:

def win_getpass(prompt='Password: ', stream=None):
    """Prompt for password with echo off, using Windows getch()."""
    if sys.stdin is not sys.__stdin__:
        return fallback_getpass(prompt, stream)
    import msvcrt
    for c in prompt:
        msvcrt.putch(c.encode('utf-8'))
    pw = ""
    while 1:
        c = msvcrt.getch()
        if c == '\r'.encode('utf-8') or c == '\n'.encode('utf-8'):
            break
        if c == '\003'.encode('utf-8'):
            raise KeyboardInterrupt
        if c == '\b'.encode('utf-8'):
            pw = pw[:-1]
        else:
            pw = pw + c.decode('utf-8')
    msvcrt.putch('\r'.encode('utf-8'))
    msvcrt.putch('\n'.encode('utf-8'))
    return pw

[bitdancer]

I'm setting this to release blocker because it sounds like a simple fix and I don't think we should release with these basic windows functions missing. If you (Steve) don't think it is important for the beta you could set it to deferred blocker.

[zooba]

I'll just remove the ifdefs. We don't support any Windows versions that don't have these functions.

[zooba]

Short of hard-coding a list of expected functions and using hasattr, anyone have any ideas about how to test stuff like this? I kind of feel like alpha/beta releases are the most efficient way to find these.

[python-dev]

New changeset d56a941865fb by Steve Dower in branch 'default':
Issue bpo-23995: Removes _WCONIO_DEFINED check as the wchar_t console functions are always available.
https://hg.python.org/cpython/rev/d56a941865fb