[PATCH] py3: partially fix pager spawning on Windows

[Yuya Nishihara]

On Sun, 16 Sep 2018 00:40:37 -0400, Matt Harbison wrote:
> # HG changeset patch
> # User Matt Harbison <matt_harbison at yahoo.com>
> # Date 1537032701 14400
> #      Sat Sep 15 13:31:41 2018 -0400
> # Node ID efffacd34255117920417dfb2d71627929499500
> # Parent  87539f615b878fe39973fb059b0531fa4fd7e6ff
> py3: partially fix pager spawning on Windows

> diff --git a/mercurial/encoding.py b/mercurial/encoding.py
> --- a/mercurial/encoding.py
> +++ b/mercurial/encoding.py
> @@ -233,6 +233,14 @@ if not _nativeenviron:
>      environ = dict((tolocal(k.encode(u'utf-8')), tolocal(v.encode(u'utf-8')))
>                     for k, v in os.environ.items())  # re-exports
>  
> +    def tonativeenv(env):
> +        return {
> +            strfromlocal(k): strfromlocal(v) for k, v in env.items()
> +        }
> +else:
> +    def tonativeenv(env):
> +        return env

Can you move this to procutil?

And pycompat.rapply() might be useful as it has a fast path for
strfromlocal == identity.


>  # How to treat ambiguous-width characters. Set to 'wide' to treat as wide.
>  _wide = _sysstr(environ.get("HGENCODINGAMBIGUOUS", "narrow") == "wide"
>                  and "WFA" or "WF")
> diff --git a/mercurial/ui.py b/mercurial/ui.py
> --- a/mercurial/ui.py
> +++ b/mercurial/ui.py
> @@ -1130,7 +1130,7 @@ class ui(object):
>  
>          try:
>              pager = subprocess.Popen(
> -                command, shell=shell, bufsize=-1,
> +                encoding.strfromlocal(command), shell=shell, bufsize=-1,

Do that only on Windows.

> diff --git a/mercurial/utils/procutil.py b/mercurial/utils/procutil.py
> --- a/mercurial/utils/procutil.py
> +++ b/mercurial/utils/procutil.py
> @@ -315,7 +315,8 @@ def shellenviron(environ=None):
>      if environ:
>          env.update((k, py2shell(v)) for k, v in environ.iteritems())
>      env['HG'] = hgexecutable()
> -    return env
> +
> +    return encoding.tonativeenv(env)

I think it's better to leave this to callers. Mixing unicode and bytes APIs
is a source of bugs.