QT: internal drag and drop of rows in QTableView,

I want to perform a sort of rows in QTableView, so that the underlying TableModel would have its data sorted, too:

If I'm not mistaken, built-in sorts in QTableView don't affect the order of rows in underlying TableModel, so I had to write a custom QTableView and custom QAbstractTableModel implementation of internal drag and drop.

To test, if it works at all, I respond to any drag of cell by reordering first and second rows:

import sys
from PyQt4.QtGui import *
from PyQt4.QtCore import *

class Model(QAbstractTableModel):
    def __init__(self):
        QAbstractTableModel.__init__(self, parent=None)
        self.data = [("elem1", "ACDC"), ("elem2", "GUNSNROSES"), ("elem3", "UFO")]
        self.setSupportedDragActions(Qt.MoveAction)

    def flags(self, index):
        if index.isValid():
            return Qt.ItemIsDragEnabled | Qt.ItemIsDropEnabled | Qt.ItemIsEditable | Qt.ItemIsEnabled | Qt.ItemIsSelectable
        else:
            return Qt.ItemIsDropEnabled | Qt.ItemIsEditable | Qt.ItemIsEnabled | Qt.ItemIsSelectable

    def rowCount(self, parent=QModelIndex()):
        return len(self.data)

    def columnCount(self, parent=QModelIndex()):
        return 1

    def data(self, index, role):
        if role == Qt.DisplayRole:
            print "row = %s" % int(index.row())
            return QVariant(self.data[int(index.row())][1])
        return QVariant()

    def headerData(self, index, orientation, role):
        if orientation == Qt.Horizontal and role == Qt.DisplayRole:
            return QVariant(str(index))
        elif orientation == Qt.Vertical and role == Qt.DisplayRole:
            return self.data[index][0]

    def dragMoveEvent(self, event):
        event.setDropAction(QtCore.Qt.MoveAction)
        event.accept()

    def moveRows(self, parent, source_first, source_last, parent2, dest):
        print "moveRows called, self.data = %s" % self.data
        self.beginMoveRows(parent, source_first, source_last, parent2, dest)

        self.data = self.data[1] + self.data[0] + self.data[2]
        self.endMoveRows()
        print "moveRows finished, self.data = %s" % self.data

class View(QTableView):
    def __init__(self, parent=None):
        QTableView.__init__(self, parent=None)
        self.setSelectionMode(self.ExtendedSelection)
        self.setDragEnabled(True)
        self.acceptDrops()
        self.setDragDropMode(self.InternalMove)
        self.setDropIndicatorShown(True)

    def dragEnterEvent(self, event):
        event.accept()

    def dragMoveEvent(self, event):
        event.accept()

    def dropEvent(self, event):
        print "dropEvent called"
        point = event.pos()
        self.model().moveRows(QModelIndex(), 0, 0, QModelIndex(), 1)
        event.accept()

    def mousePressEvent(self, event):
        print "mousePressEvent called"
        self.startDrag(event)

    def startDrag(self, event):
        print "startDrag called"
        index = self.indexAt(event.pos())
        if not index.isValid():
            return

        self.moved_data = self.model().data[index.row()]

        drag = QDrag(self)

        mimeData = QMimeData()
        mimeData.setData("application/blabla", "")
        drag.setMimeData(mimeData)

        pixmap = QPixmap()
        pixmap = pixmap.grabWidget(self, self.visualRect(index))
        drag.setPixmap(pixmap)

        result = drag.start(Qt.MoveAction)

class Application(object):
    def __init__(self):
        app = QApplication(sys.argv)

        self.window = QWidget()
        self.window.show()

        layout = QVBoxLayout(self.window)

        self.view = View()
        self.view.setModel(Model())

        layout.addWidget(self.view)
        sys.exit(app.exec_())

For some reason, this code doesn't work. It successfully starts the drag (well, almost successfully, cause it shows the previous row, instead of the current one as the drag icon), invokes mousePressEvent, startDrag, dropEvent and moveRows function, but then dies within moveRows with message:

Qt has caught an exception thrown from an event handler. Throwing
exceptions from an event handler is not supported in Qt. You must
reimplement QApplication::notify() and catch all exceptions there.

Qt has caught an exception thrown from an event handler. Throwing
exceptions from an event handler is not supported in Qt. You must
reimplement QApplication::notify() and catch all exceptions there.

terminate called after throwing an instance of 'std::bad_alloc'
  what():  std::bad_alloc
Aborted

(Duplication of paragraph in error message is intentional - that's what it outputs verbatim).

How do I debug this error? (inserting try-except in moveRows doesn't help)

Do you have a better recipe for performing internal drag-and-drops, affecting the model in tableviews?

You have several problems in your code I will address just two here:

You are calling Model.moveRows with the wrong arguments:
change self.model().moveRows(QModelIndex(), 0, 0, QModelIndex(), 1)
by self.model().moveRows(QModelIndex(), 1, 1, QModelIndex(), 0)
You are changing your data in the wrong way:
change self.data = self.data[1] + self.data[0] + self.data[2]
by self.data = [self.data[1], self.data[0] , self.data[2]]

Note: problem 1 is the one who is provoking the exception on your code. Also note that is a bad idea naming an instance variable and a function the same (Model.data)