[mintty] Problem of the control key on focus change

[Thomas Wolff]

Am 27.01.2025 um 12:17 schrieb Takashi Yano via Cygwin:
> Hi Thomas,
>
> A few days ago, Corinna asked me to check a problem of TTY.
> The problem is as follows.
>
> Reproduce steps:
> (1) Open mintty.
> (2) Open another mintty.
> (3) Place the second mintty window over the first one.
> (4) Hold ctrl key down.
> (5) Press 'd' key while holding ctrl key. The second mintty
>      window will be closed. Keep ctrl key still hold down.
> (6) Now the first mintty window is focused. Then press 'd' key
>      while holding ctrl key down.
> (7) The first mintty window will not logout but displays 'd'.
>
> I checked the pty and found the pty in the first mintty
> receives just 'd' but not Ctrl-D from mintty. In other words,
> fhandler_pty_master::write() is called with 'd'. So I suspect it
> might be a problem of mintty. Therefore, I tried old version
> of mintty. The results are:
>
> 3.7.7-1: NG
> 3.7.4-1: NG
> 2.9.6-0: OK
>
> I guess this bug(?) was introduced between 2.x.x and 3.7.x.
>
> Any idea?
>
> If you need more information from pty side, please let me know.
>
Hi Takashi,
sorry this was attributed to pty, it is an issue of mintty I was aware
of which appeared in 3.7.2.
More precisely, it slipped in with
be73970877a99548aeeab60a2572ffb04b695066 "revise AltGr handling to
support flexible right-Alt+left-Ctrl combinations (#1266)", as a
trade-off for what I meant to be a final fix for control modifier
handling. I guess I hadn't considered it serious enough to reopen the
issue for another workaround. To be reconsidered...
Thomas