IBUS:ERROR:candidatearea.c:509:candidate_area_set_candidates: assertion failed: (candidates.length < 16)

[Kyuuhachi]

Which distribution and version?:
Arch

Which desktop environment and version?:
i3

Which session type?:
X11

Which application and version?:
Seemingly any, including but probably not limited to gnome-terminal, firefox, and discord

IBus version?:
1.5.19

Issue description:
Sometimes when typing in japanese with ibus-kkc, the key for switching input methods stops working until I restart the ibus-daemon. While I've only seen the issue with ibus-kkc, the error appears to be in ibus itself.

Steps to reproduce:

1. Switch to ibus-kkc
2. Write つく (tsuku)
3. Activate conversion (default space)
4. A message appears in the daemon's output and the hotkey for toggling the IME stops working. Japanese writing still works, but no candidate popup.

Can you reproduce your problem when you restart ibus-daemon? (yes / no):
Yes, it happens every time.

Do you see any errors when you run ibus-daemon with the verbose option?:

(ibus-ui-gtk3:8722): IBUS-WARNING **: 09:32:53.001: panel.vala:255: If you launch KDE5 on xterm, export XDG_CURRENT_DESKTOP=KDE before launch KDE5.

(ibus-ui-gtk3:8722): IBUS-WARNING **: 09:32:53.047: ibus_bus_call_sync: org.freedesktop.DBus.Properties.Get: GDBus.Error:org.freedesktop.DBus.Error.Failed: No global engine.
**
IBUS:ERROR:candidatearea.c:509:candidate_area_set_candidates: assertion failed: (candidates.length < 16)

(The first two appear immediately when starting the daemon, the last appears when triggering the bug)

Can you reproduce your problem with a new user account instead of the current your account? (yes / no):
Haven't tried. I did try deleting all config files I could find (~/.config/ibus and ~/.config/ibus-kkc) though; it didn't change anything.

[Kyuuhachi]

Apparently, it's because I set the number of candidates in ibus-kkc to 16, which is above the allowed amount. I'll file a bug report to them instead, but I still think ibus shouldn't crash if it receives too many candidates (why even have a limit?).

[fujiwarat]

Sorry for the late response.
I understood the problem and will fix it.