Hello.

First, see the below bug marked as "Cannot Reproduce".

QFileSystemWatcher::removePaths: list is empty
https://bugs.kde.org/show_bug.cgi?id=393991
https://bugreports.qt.io/browse/QTBUG-68607

The bug could be reproduced in my KDE neon.

The cause is "libfcitxplatforminputcontextplugin.so", in the package "fcitx-frontend-qt5".

In the Konsole, after "fcitx-frontend-qt5" is installed:

Code: Select all

$ kde-open5 hoge.txt  # launching any Qt application
QFileSystemWatcher::removePaths: list is empty
QFileSystemWatcher::removePaths: list is empty
$ QT_IM_MODULE="" kde-open5 hoge.txt # disabling fcitx, then no message is displayed


Of course, the input method can not be used in the second case.

I don't know the development manners of KDE.
How can I report this?

Thanks.

KDE Plasma: 5.14.5
KDE Frameworks: 5.54.0
Qt: 5.11.2
Kernel: 4.15.0-43-generic

I have tried that Morten Sørvig said "Can you set a breakpoint in removePaths() and provide a stack trace?", at the last November.
The following is the log of the time.
"libfcitxplatforminputcontextplugin.so" had appeared in the backtrace.

Code: Select all

(gdb) r
Starting program: /usr/bin/kwrite
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[New Thread 0x7fffdf96d700 (LWP 8742)]
[New Thread 0x7fffd7798700 (LWP 8743)]

Thread 1 "kwrite" hit Breakpoint 5, 0x00007fffd77a1840 in QFileSystemWatcher::removePaths(QStringList const&)@plt ()
   from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforminputcontexts/libfcitxplatforminputcontextplugin.so
(gdb) c
Continuing.

Thread 1 "kwrite" hit Breakpoint 5, 0x00007ffff487e440 in QFileSystemWatcher::removePaths(QStringList const&) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
(gdb)
Continuing.

Thread 1 "kwrite" hit Breakpoint 5, 0x00007fffd77a1840 in QFileSystemWatcher::removePaths(QStringList const&)@plt ()
   from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforminputcontexts/libfcitxplatforminputcontextplugin.so
(gdb)
Continuing.

Thread 1 "kwrite" hit Breakpoint 5, 0x00007ffff487e440 in QFileSystemWatcher::removePaths(QStringList const&) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
(gdb)
Continuing.
[Thread 0x7fffdf96d700 (LWP 8742) exited]

Thread 1 "kwrite" hit Breakpoint 5, 0x00007fffd77a1840 in QFileSystemWatcher::removePaths(QStringList const&)@plt ()
   from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforminputcontexts/libfcitxplatforminputcontextplugin.so
(gdb) bt
#0  0x00007fffd77a1840 in QFileSystemWatcher::removePaths(QStringList const&)@plt () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforminputcontexts/libfcitxplatforminputcontextplugin.so
#1  0x00007fffd77aa524 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforminputcontexts/libfcitxplatforminputcontextplugin.so
#2  0x00007fffd77aa5f6 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforminputcontexts/libfcitxplatforminputcontextplugin.so
#3  0x00007fffd77acc92 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforminputcontexts/libfcitxplatforminputcontextplugin.so
#4  0x00007fffd77ace09 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforminputcontexts/libfcitxplatforminputcontextplugin.so
#5  0x00007fffe2934f38 in QXcbIntegration::~QXcbIntegration() () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#6  0x00007fffe2934fb9 in QXcbIntegration::~QXcbIntegration() () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#7  0x00007ffff4e87c1d in QGuiApplicationPrivate::~QGuiApplicationPrivate() () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#8  0x00007ffff568d6c9 in QApplicationPrivate::~QApplicationPrivate() () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#9  0x00007ffff4938733 in QObject::~QObject() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#10 0x00007ffff4904536 in QCoreApplication::~QCoreApplication() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#11 0x00007ffff568f879 in QApplication::~QApplication() () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#12 0x000055555555f202 in main ()
(gdb) c
Continuing.

Thread 1 "kwrite" hit Breakpoint 5, 0x00007ffff487e440 in QFileSystemWatcher::removePaths(QStringList const&) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
(gdb) bt
#0  0x00007ffff487e440 in QFileSystemWatcher::removePaths(QStringList const&) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#1  0x00007fffd77aa524 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforminputcontexts/libfcitxplatforminputcontextplugin.so
#2  0x00007fffd77aa5f6 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforminputcontexts/libfcitxplatforminputcontextplugin.so
#3  0x00007fffd77acc92 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforminputcontexts/libfcitxplatforminputcontextplugin.so
#4  0x00007fffd77ace09 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforminputcontexts/libfcitxplatforminputcontextplugin.so
#5  0x00007fffe2934f38 in QXcbIntegration::~QXcbIntegration() () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#6  0x00007fffe2934fb9 in QXcbIntegration::~QXcbIntegration() () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#7  0x00007ffff4e87c1d in QGuiApplicationPrivate::~QGuiApplicationPrivate() () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#8  0x00007ffff568d6c9 in QApplicationPrivate::~QApplicationPrivate() () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#9  0x00007ffff4938733 in QObject::~QObject() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#10 0x00007ffff4904536 in QCoreApplication::~QCoreApplication() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#11 0x00007ffff568f879 in QApplication::~QApplication() () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#12 0x000055555555f202 in main ()
(gdb) c
Continuing.
QFileSystemWatcher::removePaths: list is empty

Thread 1 "kwrite" hit Breakpoint 5, 0x00007fffd77a1840 in QFileSystemWatcher::removePaths(QStringList const&)@plt ()
   from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforminputcontexts/libfcitxplatforminputcontextplugin.so
(gdb) bt
#0  0x00007fffd77a1840 in QFileSystemWatcher::removePaths(QStringList const&)@plt () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforminputcontexts/libfcitxplatforminputcontextplugin.so
#1  0x00007fffd77aa551 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforminputcontexts/libfcitxplatforminputcontextplugin.so
#2  0x00007fffd77aa5f6 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforminputcontexts/libfcitxplatforminputcontextplugin.so
#3  0x00007fffd77acc92 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforminputcontexts/libfcitxplatforminputcontextplugin.so
#4  0x00007fffd77ace09 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforminputcontexts/libfcitxplatforminputcontextplugin.so
#5  0x00007fffe2934f38 in QXcbIntegration::~QXcbIntegration() () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#6  0x00007fffe2934fb9 in QXcbIntegration::~QXcbIntegration() () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#7  0x00007ffff4e87c1d in QGuiApplicationPrivate::~QGuiApplicationPrivate() () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#8  0x00007ffff568d6c9 in QApplicationPrivate::~QApplicationPrivate() () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#9  0x00007ffff4938733 in QObject::~QObject() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#10 0x00007ffff4904536 in QCoreApplication::~QCoreApplication() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#11 0x00007ffff568f879 in QApplication::~QApplication() () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#12 0x000055555555f202 in main ()
(gdb) c
Continuing.

Thread 1 "kwrite" hit Breakpoint 5, 0x00007ffff487e440 in QFileSystemWatcher::removePaths(QStringList const&) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
(gdb) bt
#0  0x00007ffff487e440 in QFileSystemWatcher::removePaths(QStringList const&) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#1  0x00007fffd77aa551 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforminputcontexts/libfcitxplatforminputcontextplugin.so
#2  0x00007fffd77aa5f6 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforminputcontexts/libfcitxplatforminputcontextplugin.so
#3  0x00007fffd77acc92 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforminputcontexts/libfcitxplatforminputcontextplugin.so
#4  0x00007fffd77ace09 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforminputcontexts/libfcitxplatforminputcontextplugin.so
#5  0x00007fffe2934f38 in QXcbIntegration::~QXcbIntegration() () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#6  0x00007fffe2934fb9 in QXcbIntegration::~QXcbIntegration() () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#7  0x00007ffff4e87c1d in QGuiApplicationPrivate::~QGuiApplicationPrivate() () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#8  0x00007ffff568d6c9 in QApplicationPrivate::~QApplicationPrivate() () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#9  0x00007ffff4938733 in QObject::~QObject() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#10 0x00007ffff4904536 in QCoreApplication::~QCoreApplication() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#11 0x00007ffff568f879 in QApplication::~QApplication() () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#12 0x000055555555f202 in main ()
(gdb) c
Continuing.
QFileSystemWatcher::removePaths: list is empty
[Thread 0x7fffd7798700 (LWP 8743) exited]
[Inferior 1 (process 8741) exited normally]
(gdb) bt
No stack.
(gdb)


The effective patch is proposed at https://gitlab.com/fcitx/fcitx-qt5/merge_requests/25, and it seems like the patch has been merged into openSUSE Tumbleweed already.
How is that in KDE neon?