[ANNOUNCEMENT] TEST: Cygwin 3.1.0-0.3

Thomas Wolff towo@towo.net
Sat Sep 7 11:53:00 GMT 2019


Am 07.09.2019 um 05:32 schrieb Takashi Yano:
> On Fri, 6 Sep 2019 12:02:36 +0200
> Thomas Wolff wrote:
>> A tool that sets up conpty itself (rawpty from
>> https://github.com/Biswa96/wslbridge2) does not work anymore with
>> conpty-enabled cygwin. This suggest that double-conpty enabling may be
>> interfering.
>> Unfortunately, I have not yet had the time to checkout the patch code in
>> detail, but my suspicion is that conpty may be enabled always, while it
>> should in fact be activated only if a non-cygwin program is run.
>> Please check out on this.
> I have not looked into this yet, but as you might expect, the pseudo
> console is always enabled behind even if it is not used.
>
> Owing to this, a cygwin program which directly accesses the console,
> as your previous test case, can work normally by just switching the
> r/w pipe to pseudo console side.
I guess you are right. We are having different use cases. For the 
generic case, the always-enabled conpty support is probably the best 
solution. However, there are exceptions. One particular case is the 
gateway to WSL (wslbridge, wslbridge2, hvpty). When you run WSL from 
cygwin with conpty enabled, unfortunately, the pseudo console will 
enforce MS's idea of what a terminal is, i.e., it handles escape 
sequences, does not pass everthing through, responds to enquiry 
sequences itself, so the terminal cannot even report itself as mintty 
(or whatever) anymore.
This unfortunate situation may hopefully resolve once they provide 
conpty "passthrough mode" as discussed in 
https://github.com/microsoft/terminal/issues/1173 and also in 
https://github.com/mintty/wsltty/issues/171#issuecomment-526778377.
So there is need to switch off conpty support for certain applications, 
e.g. via the CYGWIN environment variable. Please consider.
Thomas

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