I can reproduce.

Or wait, I actually get a different crash on this document when doing ctrl+a and the ctrl+c. It's related to sections. Discussing it a little with Casper now.

Looks as following backtrace Indicates a mismatch between 
writer->startElement("text:section", false);
vs 
writer->endElement();
calls. The section-code calls endElement() at least one time to much...

Assigning to Boudwijn cause afaik it's his code and he probably knows why it's wrong :)

Application: Words (words), signal: Aborted
[KCrash Handler]
#6  0x00007fa435bedab5 in raise () from /lib64/libc.so.6
#7  0x00007fa435beefb6 in abort () from /lib64/libc.so.6
#8  0x00007fa43694bef8 in qt_message_output (msgType=QtFatalMsg, buf=0xfcbe58 "ASSERT: \"!this->isEmpty()\" in file /home/kde4/qt/include/QtCore/qstack.h, line 67") at /home/kde4/svn/qt/src/corelib/global/qglobal.cpp:2259
#9  0x00007fa43694c074 in qt_message(QtMsgType, const char *, typedef __va_list_tag __va_list_tag *) (msgType=QtFatalMsg, msg=0x7fa436af47f0 "ASSERT: \"%s\" in file %s, line %d", ap=0x7ffff022eaf0) at /home/kde4/svn/qt/src/corelib/global/qglobal.cpp:2305
#10 0x00007fa43694c8e2 in qFatal (msg=0x7fa436af47f0 "ASSERT: \"%s\" in file %s, line %d") at /home/kde4/svn/qt/src/corelib/global/qglobal.cpp:2488
#11 0x00007fa43694baab in qt_assert (assertion=0x7fa43b6a91be "!this->isEmpty()", file=0x7fa43b6a9198 "/home/kde4/qt/include/QtCore/qstack.h", line=67) at /home/kde4/svn/qt/src/corelib/global/qglobal.cpp:2004
#12 0x00007fa43b687b49 in QStack<KoXmlWriter::Tag>::pop (this=0x7263a8) at /home/kde4/qt/include/QtCore/qstack.h:67
#13 0x00007fa43b6865b1 in KoXmlWriter::endElement (this=0x1012b10) at /home/snoopy/src/calligra/libs/odf/KoXmlWriter.cpp:180
#14 0x00007fa43bce1a4c in KoSectionEnd::saveOdf (this=0xb05750, context=...) at /home/snoopy/src/calligra/libs/kotext/KoSection.cpp:121
#15 0x00007fa43bd6d892 in KoTextWriter::Private::writeBlocks (this=0x10823c0, document=0xb82770, from=0, to=717, listStyles=..., currentTable=0x0, currentFrame=0x0, currentList=0x0) at /home/snoopy/src/calligra/libs/kotext/opendocument/KoTextWriter.cpp:1735
#16 0x00007fa43bd7384c in KoTextWriter::write (this=0x7ffff022ef60, document=0xb82770, from=0, to=717) at /home/snoopy/src/calligra/libs/kotext/opendocument/KoTextWriter.cpp:2549
#17 0x00007fa43bcbff86 in KoTextOdfSaveHelper::writeBody (this=0x7ffff022f270) at /home/snoopy/src/calligra/libs/kotext/KoTextOdfSaveHelper.cpp:72
#18 0x00007fa43bd81102 in KoTextDrag::setOdf (this=0x7ffff022f260, mimeType=0x7fa43b6a2b48 "application/vnd.oasis.opendocument.text", helper=...) at /home/snoopy/src/calligra/libs/kotext/KoTextDrag.cpp:109
#19 0x00007fa4229a37bc in TextTool::copy (this=0xd8ef40) at /home/snoopy/src/calligra/plugins/textshape/TextTool.cpp:792
#20 0x00007fa43b9a0797 in KoToolProxy::copy (this=0xd63520) at /home/snoopy/src/calligra/libs/flake/KoToolProxy.cpp:450
#21 0x00007fa43b931827 in KoCopyControllerPrivate::copy (this=0x1032ff0) at /home/snoopy/src/calligra/libs/flake/KoCopyController.cpp:62
#22 0x00007fa43b931c60 in KoCopyController::qt_metacall (this=0x10344c0, _c=QMetaObject::InvokeMetaMethod, _id=2, _a=0x7ffff022f4d0) at /home/kde4/svn/build/calligra/libs/flake/KoCopyController.moc:82
#23 0x00007fa436a7c28f in QMetaObject::metacall (object=0x10344c0, cl=QMetaObject::InvokeMetaMethod, idx=6, argv=0x7ffff022f4d0) at /home/kde4/svn/qt/src/corelib/kernel/qmetaobject.cpp:237
#24 0x00007fa436a910c5 in QMetaObject::activate (sender=0x103d5d0, m=0x7fa438b45d40, local_signal_index=1, argv=0x7ffff022f4d0) at /home/kde4/svn/qt/src/corelib/kernel/qobject.cpp:3272
#25 0x00007fa437ded5f2 in QAction::triggered (this=0x103d5d0, _t1=false) at .moc/debug-shared/moc_qaction.cpp:263
#26 0x00007fa437dec8f4 in QAction::activate (this=0x103d5d0, event=QAction::Trigger) at /home/kde4/svn/qt/src/gui/kernel/qaction.cpp:1257
#27 0x00007fa437dec660 in QAction::event (this=0x103d5d0, e=0x7ffff022fd70) at /home/kde4/svn/qt/src/gui/kernel/qaction.cpp:1183
#28 0x00007fa438d0b0e7 in KAction::event (this=0x103d5d0, event=0x7ffff022fd70) at /home/snoopy/src/kdelibs/kdeui/actions/kaction.cpp:131
#29 0x00007fa437dfd0b6 in QApplicationPrivate::notify_helper (this=0x685420, receiver=0x103d5d0, e=0x7ffff022fd70) at /home/kde4/svn/qt/src/gui/kernel/qapplication.cpp:4440
#30 0x00007fa437dfa6da in QApplication::notify (this=0x7ffff02316b0, receiver=0x103d5d0, e=0x7ffff022fd70) at /home/kde4/svn/qt/src/gui/kernel/qapplication.cpp:3840
#31 0x00007fa438e184bd in KApplication::notify (this=0x7ffff02316b0, receiver=0x103d5d0, event=0x7ffff022fd70) at /home/snoopy/src/kdelibs/kdeui/kernel/kapplication.cpp:311
#32 0x00007fa436a7411b in QCoreApplication::notifyInternal (this=0x7ffff02316b0, receiver=0x103d5d0, event=0x7ffff022fd70) at /home/kde4/svn/qt/src/corelib/kernel/qcoreapplication.cpp:732
#33 0x00007fa437dedbeb in QCoreApplication::sendEvent (receiver=0x103d5d0, event=0x7ffff022fd70) at ../../include/QtCore/../../../../qt/src/corelib/kernel/qcoreapplication.h:215
#34 0x00007fa437e3d6f4 in QShortcutMap::dispatchEvent (this=0x685548, e=0x7ffff02305a0) at /home/kde4/svn/qt/src/gui/kernel/qshortcutmap.cpp:879
#35 0x00007fa437e3be7b in QShortcutMap::tryShortcutEvent (this=0x685548, o=0xd629c0, e=0x7ffff02305a0) at /home/kde4/svn/qt/src/gui/kernel/qshortcutmap.cpp:364
#36 0x00007fa437dfa979 in QApplication::notify (this=0x7ffff02316b0, receiver=0xd629c0, e=0x7ffff02305a0) at /home/kde4/svn/qt/src/gui/kernel/qapplication.cpp:3882
#37 0x00007fa438e184bd in KApplication::notify (this=0x7ffff02316b0, receiver=0xd629c0, event=0x7ffff02305a0) at /home/snoopy/src/kdelibs/kdeui/kernel/kapplication.cpp:311
#38 0x00007fa436a7411b in QCoreApplication::notifyInternal (this=0x7ffff02316b0, receiver=0xd629c0, event=0x7ffff02305a0) at /home/kde4/svn/qt/src/corelib/kernel/qcoreapplication.cpp:732
#39 0x00007fa437dff86b in QCoreApplication::sendSpontaneousEvent (receiver=0xd629c0, event=0x7ffff02305a0) at ../../include/QtCore/../../../../qt/src/corelib/kernel/qcoreapplication.h:218
#40 0x00007fa437dfd409 in qt_sendSpontaneousEvent (receiver=0xd629c0, event=0x7ffff02305a0) at /home/kde4/svn/qt/src/gui/kernel/qapplication.cpp:5434
#41 0x00007fa437ed2cef in QKeyMapper::sendKeyEvent (keyWidget=0xd629c0, grab=false, type=QEvent::KeyPress, code=67, modifiers=..., text=..., autorepeat=false, count=1, nativeScanCode=54, nativeVirtualKey=99, nativeModifiers=20) at /home/kde4/svn/qt/src/gui/kernel/qkeymapper_x11.cpp:1867
#42 0x00007fa437ed29f4 in QKeyMapperPrivate::translateKeyEvent (this=0x6cd0f0, keyWidget=0xd629c0, event=0x7ffff02312a0, grab=false) at /home/kde4/svn/qt/src/gui/kernel/qkeymapper_x11.cpp:1837
#43 0x00007fa437e9af9f in QApplication::x11ProcessEvent (this=0x7ffff02316b0, event=0x7ffff02312a0) at /home/kde4/svn/qt/src/gui/kernel/qapplication_x11.cpp:3456
#44 0x00007fa437ed4d9c in x11EventSourceDispatch (s=0x688c30, callback=0, user_data=0x0) at /home/kde4/svn/qt/src/gui/kernel/qguieventdispatcher_glib.cpp:146
#45 0x00007fa43013cbd3 in g_main_context_dispatch () from /lib64/libglib-2.0.so.0
#46 0x00007fa43013d3b0 in ?? () from /lib64/libglib-2.0.so.0
#47 0x00007fa43013d650 in g_main_context_iteration () from /lib64/libglib-2.0.so.0
#48 0x00007fa436aad1bd in QEventDispatcherGlib::processEvents (this=0x64ef90, flags=...) at /home/kde4/svn/qt/src/corelib/kernel/qeventdispatcher_glib.cpp:415
#49 0x00007fa437ed514a in QGuiEventDispatcherGlib::processEvents (this=0x64ef90, flags=...) at /home/kde4/svn/qt/src/gui/kernel/qguieventdispatcher_glib.cpp:204
#50 0x00007fa436a71c7e in QEventLoop::processEvents (this=0x7ffff0231650, flags=...) at /home/kde4/svn/qt/src/corelib/kernel/qeventloop.cpp:149
#51 0x00007fa436a71dd2 in QEventLoop::exec (this=0x7ffff0231650, flags=...) at /home/kde4/svn/qt/src/corelib/kernel/qeventloop.cpp:201
#52 0x00007fa436a7480e in QCoreApplication::exec () at /home/kde4/svn/qt/src/corelib/kernel/qcoreapplication.cpp:1009
#53 0x00007fa437dfa252 in QApplication::exec () at /home/kde4/svn/qt/src/gui/kernel/qapplication.cpp:3714
#54 0x00007fa43c636ade in kdemain (argc=2, argv=0x7ffff0231898) at /home/snoopy/src/calligra/words/part/main.cpp:43
#55 0x0000000000400986 in main (argc=2, argv=0x7ffff0231898) at /home/kde4/svn/build/calligra/words/part/words_dummy.cpp:3

ups, stupid typo, I meaned Boudewijn :-/ sorry

I guess the problem here is that we copy+paste only part of the ODF-code. So, probably we have an KoParagraphStyle::SectionEnd without a text:section in the ODF...

I did some investigation of this a while back and I think you're right. The thing is that with the approach to saving section start/ends that we have now, where the section start saved on the first block (i think) of the section, it won't work for nested structures such as

      <text:section text:style-name="Sect1" text:name="Område1">                                                     
        <text:section text:style-name="Sect1" text:name="Område2">                                                   
          <text:p text:style-name="Standard">blah</text:p>                                                   
        </text:section>                                                                                              
        <text:p text:style-name="Standard">blah</text:p>                                       
      </text:section>

where there's no <p> in between one opening <section> and the next. It will result in a mismatch, and hence this crash.

I sort of promised Casper I would look into saving multiple section starts per block instead (perhaps as a stack), which would fix this. But school caught up with me and now I have no time :/

But that's what needs to be done.

I'll attach a minimal file I created that provokes this crash.

Created attachment 60339 [details]
Minimal example .odt that provokes this crash

Minimal example .odt that provokes this crash. It has the following structure in content.xml:

      <text:section text:style-name="Sect1" text:name="Område1">                                                     
        <text:section text:style-name="Sect1" text:name="Område2">                                                   
          <text:p text:style-name="Standard">inside inner</text:p>                                                   
        </text:section>                                                                                              
        <text:p text:style-name="Standard">insider outer, after inner</text:p>                                       
      </text:section>

Ehm. And with "I think you're right" I mean "I think you're wrong, but..." ;)

Fixed with e0334411db7390900c793c1ad938f5f0b40bfe3a