When quassel (client) is built with USE="X -qt5", the input widget's backlog/history seems prepend the input with a colour code, making text either repeated from history or entered after scrolling through history to be (in my case) black, and invalidating any "/" commands.
Steps to reproduce:
1. emerge net-irc/quassel[X,-qt5] (note that deps may be involved)
2. Connect to a network
3. Send a message
4. Press up and resend message
Text to be entered verbatim
Text is prefixed with a colour code, causing coloured text in channels without +c and invalidating any client/server commands (eg. /mode).
I suspect this is due to a dependency issue between the two USE flags.
Also, both the X and qt5 USE flags describe building the Qt5 GUI. It probably doesn't make sense to be able to install with these flags, so perhaps either use REQUIRED_USE or remove the qt5 flag to make it implicit.
Please paste the output of emerge --info =net-irc/quassel-0.12.4. qt5 use flag will be dropped in 0.13.0. So you could try with 9999 where the change is already applied.
The bug has been closed via the following commit(s):
Author: Andreas Sturmlechner <firstname.lastname@example.org>
AuthorDate: 2017-12-03 16:43:32 +0000
Commit: Andreas Sturmlechner <email@example.com>
CommitDate: 2017-12-03 17:01:39 +0000
net-irc/quassel: Drop USE=qt5, build with Qt5 unconditionally
Acked-by: Patrick Lauer <firstname.lastname@example.org>
Package-Manager: Portage-2.3.16, Repoman-2.3.6
net-irc/quassel/Manifest | 2 +-
net-irc/quassel/quassel-0.12.4.ebuild | 92 +++++++++++------------------------
2 files changed, 30 insertions(+), 64 deletions(-)