[Python-ideas] Fix default encodings on Windows

[Paul Moore]

On 12 August 2016 at 13:38, eryk sun <eryksun at gmail.com> wrote:
>> ... At this point what codepage does Python see? What codepage does
>> process X see? (Note that they are both sharing the same console).
>
> The input and output codepages are global data in conhost.exe. They
> aren't tracked for each attached process (unlike input history and
> aliases). That's how chcp.com works in the first place. Otherwise its
> calls to SetConsoleCP and SetConsoleOutputCP would be pointless.

That's what I expected, but hadn't had time to confirm (your point
about chcp didn't occur to me). Thanks.

> But IMHO all talk of using codepage 65001 is a waste of time. I think
> the trailing garbage output with this codepage in Windows 7 is
> unacceptable. And getting EOF for non-ASCII input is a show stopper.
> The problem occurs in conhost. All you get is the EOF result from
> ReadFile/ReadConsoleA, so it can't be worked around. This kills the
> REPL and raises EOFError for input(). ISTM the only people who think
> codepage 65001 actually works are those using Windows 8+ who
> occasionally need to print non-OEM text and never enter (or paste)
> anything but ASCII text.

Agreed, mucking with global state that subprocesses need was
sufficient for me, but the other issues you mention seem conclusive. I
understand Steve's point about being an improvement over 100% wrong,
but we've lived with the current state of affairs long enough that I
think we should take whatever time is needed to do it right, rather
than briefly postponing the inevitable with a partial solution.

Paul

PS I've spent the last week on a different project trying to "save
time" with partial solutions to precisely this issue, so apologies if
I'm in a particularly unforgiving mood about it right now :-(