Questions on the Locale issue

wxPython Users
#1

I have some questions regarding the handling of the issue 1637. I’ve seen that you released a new version, that fixes that point. It was an actual issue that some end users reported to me. And I fixed this with a workaround as Robin suggested in the past. This issue is now part of what I’ll scrutinize when testing this new wxPython version.

First, I had real difficulty to reproduce this issue. It was only triggered on a limited number of PCs, out of my reach (at the end user side). On this matter, do you know any easy and fast method to configure a Windows system to trigger this issue? This way I could easily test on my own in the developement process, and observe whether the 4.2 version is fixing this point.

I’m taking some time to open a discussion here, because there are some people who complain about the quality, or express doubt about the real effect of your issue fixing. I quote : “It is just the workaround, It doesn’t solve the problem but merely shuffles it around. Please revert.” So I want to understand what are these concerns? What is the actual issue remaining with this fix? Is is about the locale input which can’t be set as the Windows desktop one?

Still, as far as I can see, the fix seems to be exactly what I did to fix this issue (based on what Robin suggested). And to me, it works fine with this modification. I can’t see any issues with my app. But I don’t use date formatting not advanced locale input stuff. So what would be some adverse effects of this change?

By the way, thank you for this new version. One key point for me is the ability to run on Python3.10. I’ve seen many people having a bad time trying to install wxPython on 3.10, and now this is fixed. For these cases, I suggested them to remove 3.10 and stick to 3.9. I feel that we can also benefit a lot from the new wxWidgets 3.2 version. :slight_smile:

#2

The issue is setting any locale that is not wx.LANGUAGE_DEFAULT.

Try this:

import wx,locale,datetime
app = wx.App()
loc = wx.Locale(wx.LANGUAGE_ENGLISH_US)
print(datetime.datetime.strptime('2020', "%Y"))
Outcome

Using 4.2.0 msw on Python 3.10.5-64:

Traceback (most recent call last):
  File "c:\work\locset.py", line 4, in <module>
    print(datetime.datetime.strptime('2020', "%Y"))
  File "C:\flonidan\env\Python310\lib\_strptime.py", line 268, in <module>
    _TimeRE_cache = TimeRE()
  File "C:\flonidan\env\Python310\lib\_strptime.py", line 182, in __init__
    self.locale_time = LocaleTime()
  File "C:\flonidan\env\Python310\lib\_strptime.py", line 69, in __init__
    self.lang = _getlang()
  File "C:\flonidan\env\Python310\lib\_strptime.py", line 28, in _getlang
    return locale.getlocale(locale.LC_TIME)
  File "C:\flonidan\env\Python310\lib\locale.py", line 603, in getlocale
    return _parse_localename(localename)
  File "C:\flonidan\env\Python310\lib\locale.py", line 511, in _parse_localename
    raise ValueError('unknown locale: %s' % localename)
ValueError: unknown locale: en-US

The problem is in the Python stdlib: https://github.com/python/cpython/issues/87281. wxWidgets calls the C library setlocale function with a value that is perfectly legitimate but that locale.getlocale chooses to reject.

I can no longer remember what specific issue I saw with Change InitLocale to just do locale.setlocale(locale.LC_ALL, "C") to … · wxWidgets/Phoenix@040c59f · GitHub. I think my conclusion at the time was that the problem couldn’t be properly solved in App.InitLocale, whatever you write there, and I wanted to avoid a proliferation of half-baked workarounds. Something like that.

#3

I will check tomorrow at work the configuration of the PCs that were causing this problem for me.

In my wx App I was not using any locale definition.
I ported my application from python 2.7 with 3.1.1wx to python 3.7.9 with 4.2.0wx and the application would crash on a couple of PCs.

I had to add in the wx.locale definition suggested by Robin to be able to run it.

#4

I have checked on the PC which had the issue & my PC which doesnt have the issue.
On the PC which has the issue, it is installed with Windows 10 & Suisse French as the base Operating system language.
The other PCs which dont have a problem are installed with Windows 10 & American English as the base operating system language (although all using Suisse French or French-French as the keyboard language locale)

In my case, I was not defining any python locale() or wx.locale() in my code.
However, as @AndersMunch mentions, if you use a function which itself requires a locale (datetime.strptime() as an example) then the application will crash.

In all my wx applications I now add the following which works on all PCs:

locale.setlocale(locale.LC_ALL, "C")
self.locale = wx.Locale()

Another comment is that I am using Python 3.7.9.
In the releases notes/threads from Robin he suggests that the locale change from Python occurs from 3.8
I can only assume that whatever change was made was also backported to other versions with the minor releases.

There is a small script I ran showing differences between Python 2.7 & Python 3.7 in a post I made on StackOverflow before I found the threads here from Robin.

Happy to provide any more information if required.