Created attachment 143684 [details]
TEST FILE

SUMMARY

If Kate is performing "Search and Replace" operation one can switch to another opened tab, then switch back and get a crash.

STEPS TO REPRODUCE
1. Unpack and open the attached text file.
2. Open a new empty tab (Ctrl+T)
3. Switch back to the file
4. Search and replace with values " and an empty string to get rid of " characters in the text. (Use Ctrl+F then "Switch to power search and replace bar")
5. While text is replacing (the file is very big) switch to a new tab.
6. Switch back to the tab where text is replaced

OBSERVED RESULT

Kate crashed

EXPECTED RESULT

Kate should show document

SOFTWARE/OS VERSIONS
Operating System: Kubuntu 21.10
KDE Plasma Version: 5.22.5
KDE Frameworks Version: 5.86.0
Qt Version: 5.15.2
Kernel Version: 5.13.0-21-generic (64-bit)
Graphics Platform: X11
Processors: 4 × Intel® Core™ i7-3520M CPU @ 2.90GHz
Memory: 7,6 GiB of RAM
Graphics Processor: Mesa DRI Intel® HD Graphics 4000

ADDITIONAL INFORMATION

I was able to debug it a bit with gdb to get a backtrace:

(gdb) backtrace
#0  0x00007effc10f4cd9 in KateSearchBar::findOrReplaceAll() () from /lib/x86_64-linux-gnu/libKF5TextEditor.so.5
#1  0x00007effbf3d573e in QObject::event(QEvent*) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#2  0x00007effbfe946b3 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /lib/x86_64-linux-gnu/libQt5Widgets.so.5
#3  0x00007effbf3a816a in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007effbf3ab257 in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) ()
   from /lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007effbf401ef7 in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007effbd3768bb in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#7  0x00007effbd3c9f08 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#8  0x00007effbd374003 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#9  0x00007effbf401548 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) ()
   from /lib/x86_64-linux-gnu/libQt5Core.so.5
#10 0x00007effbf3a6a9b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#11 0x00007effbf3af024 in QCoreApplication::exec() () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#12 0x000055c0f24d865e in main (argc=1, argv=0x7fff27294a78) at /tmp/kate/kate/main.cpp:700