"Po Lu" <luangruo@yahoo.com> writes:

> Trey Peacock <gpg@treypeacock.com> writes:
>
>> Neither of the WMs I mentioned use GNOME Shell, but they do both use
>> wlroots. Looking into this, it seems that any wlroots based Wayland
>> compositor will use GDK_MOD4_MASK as Super. However, mutter (GNOME's
>> WM) uses GDK_SUPER_MASK. Rebuilding emacs with the below patch seems
>> to have fixed the issue. I'm not sure if there could be further
>> implications for pgtk_emacs_to_gtk_modifiers.
>
> GDK_MOD4_MASK is a real modifier.  GDK_SUPER_MASK is a "virtual
> modifier" mask.
>
> The entire point of that change was to rely on GDK to compute the
> correspondence between real modifiers and virtual modifiers instead of
> doing it ourselves, since a real modifier can mean any number of virtual
> modifiers and vice versa.

It does not seem to be a requirement of GTK 3.2 or XKB to send virtual
modifiers. The only compositor I have come across that actually sends a
virtual modifier is mutter/GNOME. Neither wlroots nor Weston, the
Wayland reference implementation, send them. I'm unsure about Plasma,
but I believe this highlights an issue with the development of pgtk, if
it is meant to be targeted towards wayland users it should be tested
against more than just one compositor.

> Hard-coding the meaning of GDK_MOD4_MASK would be a step backwards.

The experience of a user updating Emacs and realizing a key is no longer
recognized, without any notification or justification would also be a
step backwards.

> This seems to either be a bug in wlroots or GDK, so I suggest that a bug
> be filed with their developers.

I have spoken with devs of wlroots & wayland over IRC and they seem to
agree that it is not necessary. I don't mean to be adversarial but would
be happy to see this change amended to incorporate the entirety of
wayland compositors.