I'm using a QTreeView and a custom model to display a tree of MIME types by group. The top-level items are the MIME groups (application, image, text,...) and each one has the list of MIME types belonging to that group (application/octet-stream, text/plain,...).

I get the selected MIME type and clear the selection, then I remove it from my internal data structures and I want to remove it also from the model. I'm using this method:

Qt Code: 
  1. void MIMETypesModel::removeMimeType(QString mimeType)
  2. {
  3. 	QString group = mimeType.left(mimeType.indexOf('/'));
  4. 	MIMETypesItem *groupItem = m_rootItem->findChild(group);
  5. 	if(!groupItem)
  6. 		return;
  7.  
  8. 	MIMETypesItem *mimeItem = groupItem->findChild(mimeType);
  9. 	if(mimeItem != NULL) {
  10. 		QModelIndex parentIndex = createIndex(groupItem->row(), 0, m_rootItem);
  11. 		beginRemoveRows(parentIndex, mimeItem->row(), mimeItem->row());
  12. 		groupItem->removeChild(mimeItem);
  13. 		endRemoveRows();
  14. 	}
  15.  
  16. 	if(groupItem->childCount() == 0) {
  17. 		beginRemoveRows(QModelIndex(), groupItem->row(), groupItem->row());
  18. 		m_rootItem->removeChild(groupItem);
  19. 		endRemoveRows();
  20. 	}
  21. }
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MIMETypesItem is based in the "Simple Tree Model" example from QT. MIMETypesItem::findChild() returns the child item that contains the specified MIME type/group (it searches for the string in the child items).

It's really strange, but if I remove, let's say, the second MIME type in the first group, it works flawlessly. But if I remove, let's say, the tenth MIME type in the first group, the program crashes in the beginRemoveRows() with a SIGABRT and this is printed to stdout:

ASSERT failure in QList<T>::at: "index out of range", file /usr/lib/qt4/include/QtCore/qlist.h, line 361
This is the backtrace:

Qt Code: 
  1. (gdb) bt
  2. #0  0xffffe410 in __kernel_vsyscall ()
  3. #1  0xb72a37d0 in raise () from /lib/libc.so.6
  4. #2  0xb72a4ea3 in abort () from /lib/libc.so.6
  5. #3  0xb75044ec in qt_message_output (msgType=QtFatalMsg,
  6.     buf=0xbf99f4d0 "ASSERT failure in QList<T>::at: \"index out of range\", file /usr/lib/qt4/include/QtCore/qlist.h, line 361")
  7.     at global/qglobal.cpp:1958
  8. #4  0xb750453e in qFatal (msg=0xb75e9e8c "ASSERT failure in %s: \"%s\", file %s, line %d") at global/qglobal.cpp:2174
  9. #5  0xb7504574 in qt_assert_x (where=0x80960a3 "QList<T>::at", what=0x8096090 "index out of range",
  10.     file=0x809606c "/usr/lib/qt4/include/QtCore/qlist.h", line=361) at global/qglobal.cpp:1731
  11. #6  0x080902cc in QList<MIMETypesItem*>::at (this=0x82cb2bc, i=11) at /usr/lib/qt4/include/QtCore/qlist.h:361
  12. #7  0x0808f8b9 in MIMETypesItem::child (this=0x82cb2b8, row=11) at mimetypesitem.cpp:80
  13. #8  0x0808ee78 in MIMETypesModel::index (this=0x82cacf0, row=11, column=0, parent=@0xbf9a1bec) at mimetypesmodel.cpp:104
  14. #9  0xb7d2ceec in QTreeView::rowsAboutToBeRemoved (this=0x82c0dd8, parent=@0xbf9a1bec, start=11, end=11) at itemviews/qtreeview.cpp:1341
  15. #10 0xb7cfd46e in QAbstractItemView::qt_metacall (this=0x82c0dd8, _c=QMetaObject::InvokeMetaMethod, _id=17, _a=0xbf9a1b54)
  16.     at .moc/debug-shared/moc_qabstractitemview.cpp:176
  17. #11 0xb7d8071e in QTreeView::qt_metacall (this=0x82c0dd8, _c=QMetaObject::InvokeMetaMethod, _id=43, _a=0xbf9a1b54)
  18.     at .moc/debug-shared/moc_qtreeview.cpp:88
  19. #12 0xb75c7614 in QMetaObject::activate (sender=0x82cacf0, from_signal_index=9, to_signal_index=9, argv=0xbf9a1b54)
  20.     at kernel/qobject.cpp:2671
  21. #13 0xb75c845f in QMetaObject::activate (sender=0x82cacf0, m=0x80b9a58, local_signal_index=5, argv=0xbf9a1b54) at kernel/qobject.cpp:2709
  22. #14 0xb75e8a13 in QAbstractItemModel::rowsAboutToBeRemoved (this=0x82cacf0, _t1=@0xbf9a1bec, _t2=11, _t3=11)
  23.     at .moc/debug-shared/moc_qabstractitemmodel.cpp:149
  24. #15 0xb75ac044 in QAbstractItemModel::beginRemoveRows (this=0x82cacf0, parent=@0xbf9a1bec, first=11, last=11)
  25.     at kernel/qabstractitemmodel.cpp:1727
  26. #16 0x0808e519 in MIMETypesModel::removeMimeType (this=0x82cacf0, mimeType=@0xbf9a1c6c) at mimetypesmodel.cpp:215
  27. #17 0x080870d3 in MIMETypesEditor::removeMimeType (this=0x8255b90, type=@0xbf9a1ca0) at mimetypeseditor.cpp:291
  28. #18 0x0808ab1a in MIMETypesPanel::removeMimeType (this=0x82bab58) at mimetypespanel.cpp:172
  29. #19 0x08092294 in MIMETypesPanel::qt_metacall (this=0x82bab58, _c=QMetaObject::InvokeMetaMethod, _id=0, _a=0xbf9a21ec)
  30.     at moc_mimetypespanel.cpp:67
  31. #20 0xb75c7614 in QMetaObject::activate (sender=0x82c4078, from_signal_index=25, to_signal_index=26, argv=0xbf9a21ec)
  32.     at kernel/qobject.cpp:2671
  33. #21 0xb75c7801 in QMetaObject::activate (sender=0x82c4078, m=0xb7ea3690, from_local_signal_index=2, to_local_signal_index=3, argv=0xbf9a21ec)
  34.     at kernel/qobject.cpp:2718
  35. #22 0xb7d79148 in QAbstractButton::clicked (this=0x82c4078, _t1=false) at .moc/debug-shared/moc_qabstractbutton.cpp:170
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Any idea?