bug#64310: 29.0.92; pure-GTK warning under Wayland

[Eli Zaretskii <eliz@gnu.org>]

Ping!  Pankaj, can you please answer Po Lu's questions?

> From: Po Lu <luangruo@yahoo.com>
> Cc: Pankaj Jangid <pankaj@codeisgreat.org>,  64310@debbugs.gnu.org
> Date: Sat, 22 Jul 2023 21:38:47 +0800
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > Ping!  Can we make some progress in this issue?
> >
> >> From: Pankaj Jangid <pankaj@codeisgreat.org>
> >> Cc: Eli Zaretskii <eliz@gnu.org>,  64310@debbugs.gnu.org
> >> Date: Thu, 13 Jul 2023 15:00:16 +0530
> >> 
> >> Po Lu <luangruo@yahoo.com> writes:
> >> 
> >> >>> > Pankaj Jangid <pankaj@codeisgreat.org> writes:
> >> >>> >
> >> >>> >> Exec=sh -c "u=\\$(echo \\"\\$1\\" | sed 's/[\\\\\\"]/\\\\\\\\&/g');
> >> >>> >> exec emacsclient --alternate-editor= --display=\\"\\$DISPLAY\\"
> >> >>> >> --eval \\"(message-mailto \\\\\\"\\$u\\\\\\")\\"" sh %u
> >> >>> >
> >> >>> > I think this line here is the problem: it will make emacsclient try to
> >> >>> > use the Xwayland display.  What happens if you delete the `--display'
> >> >>> > argument from this command line?  Emacsclient should be smart enough to
> >> >>> > figure out which display to use from the environment alone.
> >> >>> 
> >> >>> Nope. I removed the "--display=..."  argument from
> >> >>> .local/share/emacs/29.0.92/etc/emacsclient-mail.desktop. It did not make
> >> >>> any difference.
> >> >>> 
> >> >
> >> > Sorry, I must've missed that reply.  Pankaj, what if you replace
> >> > --display="$DISPLAY" with --display="$WAYLAND_DISPLAY"?
> >> >
> >> 
> >> Nothing changes. When there is no default email handler configured
> >> i.e. when Firefox is set to ask each time. It shows two options for
> >> Emacs - (1) Emacs(Mail, Client) (2) Emacs (Mail). When I select the
> >> first one, it shows error that I reported. If I select option (2), Emacs
> >> launches without any warning (desired behaviour).
> >> 
> >> 
> 
> I tried to reproduce this myself a few weeks ago, but I guess the line
> eater ate my reply.
> 
> Unfortunately, the desktop file works as expected.  Are you sure the
> emacsclient you've installed corresponds to a PGTK build of Emacs?  If
> it's part of an Emacs installation built with another window system,
> PGTK-specific code within won't be present, demonstrating symptoms
> similar to what you are experiencing.