[PATCH 3/3] fhandler_pty_slave::setup_locale: respect charset == "UTF-8"

[Takashi Yano]

On Thu, 10 Sep 2020 23:16:10 +0900
Takashi Yano  wrote:

> On Thu, 10 Sep 2020 16:04:07 +0200
> Corinna Vinschen wrote:
> 
> > Hi Takashi,
> > 
> > On Sep 10 09:15, Takashi Yano via Cygwin-patches wrote:
> > > On Wed, 9 Sep 2020 09:21:23 +0200
> > > Corinna Vinschen wrote:
> > > > Takashi, does the patch from
> > > > https://cygwin.com/pipermail/cygwin-developers/2020-August/011951.html
> > > > still apply to the latest from master?  Question is, shouldn't the
> > > > Windows calls setting the codepage be only called if started from
> > > > child_info_spawn::worker for non-Cygwin executables?
> > > 
> > > I'd propose the patch:
> > > 
> > > diff --git a/winsup/cygwin/fhandler_tty.cc b/winsup/cygwin/fhandler_tty.cc
> > > index 37d033bbe..95b28c3da 100644
> > > --- a/winsup/cygwin/fhandler_tty.cc
> > > +++ b/winsup/cygwin/fhandler_tty.cc
> > > @@ -1830,7 +1830,11 @@ fhandler_pty_slave::setup_locale (void)
> > >    extern UINT __eval_codepage_from_internal_charset ();
> > > 
> > >    if (!get_ttyp ()->term_code_page)
> > > -    get_ttyp ()->term_code_page = __eval_codepage_from_internal_charset ();
> > > +    {
> > > +      get_ttyp ()->term_code_page = __eval_codepage_from_internal_charset ();
> > > +      SetConsoleCP (get_ttyp ()->term_code_page);
> > > +      SetConsoleOutputCP (get_ttyp ()->term_code_page);
> > > +    }
> > >  }
> > > 
> > >  void
> > > 
> > > However, Johannes insists setting codepage for non-cygwin apps
> > > even when pseudo console is enabled, which I cannot agree.
> > > 
> > > Actually, I hesitate even the patch above, however, it seems to
> > > be necessary for msys apps in terms of backward compatibility.
> > 
> > If we do as above, doesn't that mean the invocation of convert_mb_str in
> > fhandler_pty_master::accept_input, as well as the second invocation of
> > convert_mb_str in fhandler_pty_master::pty_master_fwd_thread are
> > redundant?  Both are only called if get_ttyp ()->term_code_page differs
> > from the input or output console codepage.  Given the above setting of
> > the console CP to term_code_page, this would never be the case, right?
> 
> You are right by default. However, if user change the code page using
> chcp.com, conversion does work.

Not only user, but also app may change the codepage by SetConsoleCP()
and SetConsoleOutputCP().

-- 
Takashi Yano <takashi.yano@nifty.ne.jp>