Re: im-config | Use im-config on Wayland without uninstalling IBus (!5)

[Osamu Aoki <osamu@debian.org>]

Hi Gunnar,

I admit my misunderstanding of gnome-session code and I have related
questions to you.

Q1: Leaving GTK_IM_MODULE unset by gnome session is not just for
   
wayland but also for X.  Am I correct?

Q2: Leaving GTK_IM_MODULE unset or NULL string is that equivalent of
    setting GTK_IM_MODULE=xim .  Am I correct?

The background of my question is below.

On Thu, 2020-07-23 at 08:11 +0200, Gunnar Hjalmarsson wrote:
> On 2020-07-20 04:28, Changwoo Ryu wrote:
> > There's an issue about the on-screen keyboard with
> > GTK_IM_MODULE=ibus. IIRC it's about entering accented characters by
> > long-press.
> 
> Actually it does not show up. At all.
> 
> > But it is not an issue for CJK users, as the current implementation
> > of GNOME on-screen keyboard is useless for CJK languages anyway.
> 
> That's a misleading description of the effects.
> 
> Debian's GNOME is shipped with GNOME on Wayland by default, 

But Debian's GNOME has an option to be started on X, too.

> and both 
> ibus and im-config are there by default. With the current state of 
> im-config in the devel branch, the on screen keyboard (OSK) is 
> consequently broken by default for everyone.
> 
> We know that the GNOME developers have integrated IBus into the
> desktop 
> in such a way that GTK_IM_MODULE is supposed to *not* be set to
> "ibus", 
> at least not for Wayland sessions. 

No wonder you know such details around this issue.

Author: Gunnar Hjalmarsson <gunnarhj@ubuntu.com>  2016-08-14 10:32:00
7060744a ("main: Don't override IM variables", 2016-08-13)

I somehow thought code around here was setting GTK_IM_MODULE.
I was wrong. In the gnome-session source, gnome-session/main.c


          {
                  gchar *ibus_path;
  
                  ibus_path = g_find_program_in_path("ibus-daemon");
  
                  if (ibus_path) {
                          const gchar *p;
                          p = g_getenv ("QT_IM_MODULE");

                          if (!p || !*p)
                                  p = "ibus";
                          gsm_util_setenv ("QT_IM_MODULE", p);
                          p = g_getenv ("XMODIFIERS");
                          if (!p || !*p)
                                  p = "@im=ibus";
                          gsm_util_setenv ("XMODIFIERS", p);
                  }
  
                  g_free (ibus_path);
          }

So in a plain language:
GNOME session checks if ibus-daemon available
  --> if not, don't bother any more for environment variables. 
GNOME session checks if QT_IM_MODULE is not set yet
  --> if not, set it to "ibus".
GNOME session checks if XMODIFIERS is not set yet
  --> if not, set it to @im=ibus".

Interesting...  (This seems to be the root cause of my confusion.  I
somehow thought GTK_IM_MODULE was also set to ibus here.) 

But this is also for X.  So even under X, GTK_IM_MODULE=xim is used
(not GTK_IM_MODULE=ibus).

This is not good for X.

(I will take a look at your patch now)

Osamu