[Impact]
Qt applications incorrectly interpret keyboard input when running over some VNC clients such as TightVNC.
[Test Case]
1. Have Ubuntu 18.04 LTS installed with VNC server
2. Connect to Ubuntu 18.04 LTS from other machine with VNC client
3. Launch any Qt5 based application such as `assistant`, `kate` or `retext`
4. Press keyboard combination on VNC client
Expected results:
all keypresses are recognized successfully
Actual results:
* <Shift> produces `1`
* <Alt> produces `5`
* <`> produces `p`
* <Delete> and <Backspace> are not working
* all letters are messed
[Proposed Fix]
The proposed fix is a backport of two upstream commits: the second being the actual fix, the first one is some refactoring of the code to make it easier to write the second. The commits are:
- https://code.qt.io/cgit/qt/qtbase.git/commit/?id=f8b164e1c37ca901
- https://code.qt.io/cgit/qt/qtbase.git/commit/?id=3edcd9420e3ad661
[Regression Potential]
Most of the new code is triggered only when the keymap is missing rules, models, or layout (i.e. rmlvo_is_incomplete == true). This minimizes the risk of regressions when working with simple X11 server. In any case, the potential regressions will be related to input handling.
[Other Info]
Note:
only Qt applications are affected, the GTK-based work as expected (including Chromium from which I write this bug-report)
ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: qt5-assistant 5.9.5-0ubuntu1
Uname: Linux 4.4.78-perf+ aarch64
NonfreeKernelModules: wlan exfat
ApportVersion: 2.20.9-0ubuntu7
Architecture: armhf
CurrentDesktop: MATE
Date: Tue Jun 4 00:46:55 2019
ProcEnviron:
TERM=xterm
PATH=(custom, no user)
LANG=en_US.UTF-8
SHELL=/bin/bash
SourcePackage: qttools-opensource-src
UpgradeStatus: No upgrade log present (probably fresh install)
The CPU architecture is not the problem.
Got the same behavior on amd64 <-> amd64 connection with default settings of TightVNC server.