Random crashing in Wayland when not using keyboard #131
Description
I noticed Fedora KDE activates the on-screen keyboard by default. This results in random crashes in coredumpctl:
maliit/keyboard#8 0x00007ffae560dd5e in qBadAlloc () at global/qglobal.cpp:3372
maliit/keyboard#9 0x00007ffae56152e9 in QString::QString (this=this@entry=0x7fff1e6ad1b8, size=size@entry=-2140115104) at text/qstring.cpp:2168
maliit/keyboard#10 0x00007ffae5878322 in QUtf8::convertToUnicode (chars=0x55df11ae0ba8 "", len=-2140115104) at codecs/qutfcodec.cpp:485
maliit/keyboard#11 0x00007ffae56e07e9 in QString::fromUtf8_helper (str=<optimized out>, size=<optimized out>) at text/qstring.cpp:5598
maliit/keyboard#12 0x00007ffae734f756 in QString::fromUtf8 (str=<optimized out>, size=-2140115104) at /usr/include/qt5/QtCore/qstring.h:703
maliit/keyboard#13 Maliit::Wayland::InputMethodContext::zwp_input_method_context_v1_surrounding_text (this=0x55df11b79180, text=<optimized out>, cursor=0, anchor=2154852192) at /usr/src/debug/maliit-framework-2.3.0-9.fc42.x86_64/connection/waylandinputmethodconnection.cpp:601
maliit/keyboard#14 0x00007ffae734c4ba in QtWayland::zwp_input_method_context_v1::handle_surrounding_text (data=0x55df11b79180, object=<optimized out>, text=<optimized out>, cursor=0, anchor=2154852192) at /usr/src/debug/maliit-framework-2.3.0-9.fc42.x86_64/redhat-linux-build/qwayland-input-method-unstable-v1.cpp:207
maliit/keyboard#15 0x00007ffae54a8056 in ffi_call_unix64 () at ../src/x86/unix64.S:104
maliit/keyboard#16 0x00007ffae54a3d08 in ffi_call_int (cif=cif@entry=0x7fff1e6ad460, fn=fn@entry=0x7ffae734c450 <QtWayland::zwp_input_method_context_v1::handle_surrounding_text(void*, zwp_input_method_context_v1*, char const*, unsigned int, unsigned int)>, rvalue=<optimized out>, rvalue@entry=0x0, avalue=avalue@entry=0x7fff1e6ad530, closure=closure@entry=0x0) at ../src/x86/ffi64.c:673
maliit/keyboard#17 0x00007ffae54a670e in ffi_call (cif=cif@entry=0x7fff1e6ad460, fn=0x7ffae734c450 <QtWayland::zwp_input_method_context_v1::handle_surrounding_text(void*, zwp_input_method_context_v1*, char const*, unsigned int, unsigned int)>, rvalue=rvalue@entry=0x0, avalue=avalue@entry=0x7fff1e6ad530) at ../src/x86/ffi64.c:710
maliit/keyboard#18 0x00007ffae628c422 in wl_closure_invoke (closure=closure@entry=0x7ffabc006f70, target=<optimized out>, target@entry=0x7ffabc005b60, opcode=opcode@entry=0, data=<optimized out>, flags=1) at ../src/connection.c:1228
maliit/keyboard#19 0x00007ffae628cc79 in dispatch_event (display=display@entry=0x55df117d6a50, queue=queue@entry=0x55df117d6b48) at ../src/wayland-client.c:1674
maliit/keyboard#20 0x00007ffae628d063 in dispatch_queue (display=0x55df117d6a50, queue=0x55df117d6b48) at ../src/wayland-client.c:1820
maliit/keyboard#21 wl_display_dispatch_queue_pending (display=0x55df117d6a50, queue=0x55df117d6b48) at ../src/wayland-client.c:2062
maliit/keyboard#22 0x00007ffae0ea3a5e in QtWaylandClient::QWaylandDisplay::flushRequests (this=<optimized out>) at /usr/src/debug/qt5-qtwayland-5.15.17-1.fc42.x86_64/src/client/qwaylanddisplay.cpp:255
maliit/keyboard#23 0x00007ffae584c6b4 in QObject::event (this=<optimized out>, e=<optimized out>) at kernel/qobject.cpp:1347
maliit/keyboard#24 0x00007ffae581f258 in QCoreApplication::notifyInternal2 (receiver=0x55df117d68f0, event=0x7ffac4002610) at kernel/qcoreapplication.cpp:1064
maliit/keyboard#25 0x00007ffae581f472 in QCoreApplication::sendEvent (receiver=<optimized out>, event=<optimized out>) at kernel/qcoreapplication.cpp:1462
maliit/keyboard#26 0x00007ffae5822788 in QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=event_type@entry=0, data=0x55df117cb210) at kernel/qcoreapplication.cpp:1821
maliit/keyboard#27 0x00007ffae5822a30 in QCoreApplication::sendPostedEvents (receiver=<optimized out>, event_type=0) at kernel/qcoreapplication.cpp:1680
maliit/keyboard#28 0x00007ffae5874dcf in postEventSourceDispatch (s=0x55df11855be0) at kernel/qeventdispatcher_glib.cpp:277
maliit/keyboard#29 0x00007ffae6aeb880 in g_main_dispatch (context=0x7ffacc000ed0) at ../glib/gmain.c:3398
maliit/keyboard#30 g_main_context_dispatch_unlocked (context=0x7ffacc000ed0) at ../glib/gmain.c:4249
maliit/keyboard#31 0x00007ffae6af47c8 in g_main_context_iterate_unlocked (context=context@entry=0x7ffacc000ed0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ../glib/gmain.c:4314
maliit/keyboard#32 0x00007ffae6af4973 in g_main_context_iteration (context=0x7ffacc000ed0, may_block=1) at ../glib/gmain.c:4379
maliit/keyboard#33 0x00007ffae5874867 in QEventDispatcherGlib::processEvents (this=0x55df1184c680, flags=...) at kernel/qeventdispatcher_glib.cpp:423
maliit/keyboard#34 0x00007ffae581dbc2 in QEventLoop::exec (this=this@entry=0x7fff1e6adaf0, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:69
maliit/keyboard#35 0x00007ffae5825fa4 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1375
maliit/keyboard#36 0x000055deeaa6bf1d in main (argc=<optimized out>, argv=<optimized out>) at /usr/src/debug/maliit-keyboard-2.3.1-10.fc42.x86_64/src/keyboard/keyboard.cpp:40
QtWayland::zwp_input_method_context_v1::handle_surrounding_text appears to be called with an invalid anchor, which gets passed unchecked into an invalid length to convert via QString::fromUtf8, resulting in an abort. I don't know why this happens.