PyQt4 setItemDelegateForRow causing segmentation fault

Question

I'm attempting to set an editor delegate on my QTableView specific to each row of data by using the QTableView.setItemDelegateForRow() method. When I set a delegate on multiple rows it causes PyQt4 to segmentation fault. It seems at least partially related to using the same variable to store different instances of the delegate class, like so:

# This code causes a segmentation fault
delegate = ListDelegate(choices0)
tableView.setItemDelegateForRow(0,delegate)
delegate = ListDelegate(choices1)
tableView.setItemDelegateForRow(1,delegate)

However, if I use different variables it seems to work properly, eg:

# This code works to set the delegate by row
delegate0 = ListDelegate(choices0)
tableView.setItemDelegateForRow(0,delegate0)
delegate1 = ListDelegate(choices1)
tableView.setItemDelegateForRow(1,delegate1)

I have an example of code that causes the segmentation fault which I'll include at the end. I've tested this against python 2.7 on both Ubuntu Linux and Windows 7, both 64-bit.

I realize that the quick fix would be to just use seperate variables, but in my actual program (not this sample code) I'm trying to set the delegates in a loop, and using a dictionary or list to store the delegates doesn't seem to solve the problem.

Sample application:

from PyQt4 import QtGui, QtCore
import sys

class PaletteListModel(QtCore.QAbstractListModel):

    def __init__(self, colors = [], parent = None):
        QtCore.QAbstractListModel.__init__(self,parent)
        self.__colors = colors

    # required method for Model class
    def rowCount(self, parent):
        return len(self.__colors)

    # optional method for Model class
    def headerData(self, section, orientation, role):
        if role == QtCore.Qt.DisplayRole:
            if orientation == QtCore.Qt.Horizontal:
                return QtCore.QString("Palette")
            else:
                return QtCore.QString("Color %1").arg(section)

        if role == QtCore.Qt.ToolTipRole:
            if orientation == QtCore.Qt.Horizontal:
                return QtCore.QString("Horizontal Header %s Tooltip" % str(section))
            else:
                return QtCore.QString("Vertical Header %s Tooltip" % str(section))


    # required method for Model class
    def data(self, index, role):
        # index contains a QIndexClass object. The object has the following
        # methods: row(), column(), parent()

        row = index.row()
        value = self.__colors[row]

        # keep the existing value in the edit box
        if role == QtCore.Qt.EditRole:
            return self.__colors[row].name()

        # add a tooltip
        if role == QtCore.Qt.ToolTipRole:
            return "Hex code: " + value.name()

        if role == QtCore.Qt.DecorationRole:
            pixmap = QtGui.QPixmap(26,26)
            pixmap.fill(value)

            icon = QtGui.QIcon(pixmap)

            return icon

        if role == QtCore.Qt.DisplayRole:

            return value.name()

    def setData(self, index, value, role = QtCore.Qt.EditRole):
        row = index.row()

        if role == QtCore.Qt.EditRole:
            color = QtGui.QColor(value)

            if color.isValid():
                self.__colors[row] = color
                self.dataChanged.emit(index, index)
                return True

        return False

    # implment flags() method
    def flags(self, index):
        return QtCore.Qt.ItemIsEditable | QtCore.Qt.ItemIsEnabled | QtCore.Qt.ItemIsSelectable

class ListDelegate(QtGui.QStyledItemDelegate):
    def __init__(self, colors = QtCore.QStringList(), parent = None):
        #super(ListDelegate, self).__init__()
        QtGui.QStyledItemDelegate.__init__(self,parent)
        self.__colors = colors
        #self.__current  = current

    def createEditor(self, parent, option, index):
        ed = QtGui.QComboBox(parent)
        ed.setEditable(True)

        # add each settings option to the combobox
        for s in self.__colors:
            ed.addItem(s)

        return ed


if __name__ == '__main__':


    app = QtGui.QApplication(sys.argv)
    app.setStyle("plastique")

    data = QtCore.QStringList()
    data << "one" << "two" << "three" << "four" << "five"

    tableView = QtGui.QTableView()
    tableView.show()

    red   = QtGui.QColor(255,0,0)
    green = QtGui.QColor(0,255,0)
    blue  = QtGui.QColor(0,0,255)

    model = PaletteListModel([red, green, blue])

    choices0 = QtCore.QStringList(["#FF0000","#00FF00","#0000FF"])
    choices1 = QtCore.QStringList(["#FF0000","#0000FF"])

    # This code works to set the delegate by row
    delegate0 = ListDelegate(choices0)
    tableView.setItemDelegateForRow(0,delegate0)
    delegate1 = ListDelegate(choices1)
    tableView.setItemDelegateForRow(1,delegate1)

    # This code causes a segmentation fault
    delegate = ListDelegate(choices0)
    tableView.setItemDelegateForRow(0,delegate)
    delegate = ListDelegate(choices1)
    tableView.setItemDelegateForRow(1,delegate)

    tableView.setModel(model)
    tableView.horizontalHeader()

    sys.exit(app.exec_())

Stacktrace (from Ubuntu box) though I don't really know how to interpret it:

gdb python2.7-dbg
GNU gdb (GDB) 7.5-ubuntu
Copyright (C) 2012 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /usr/bin/python2.7-dbg...done.
(gdb) run TestDelegateForRow.py
Starting program: /usr/bin/python2.7-dbg TestDelegateForRow.py
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[New Thread 0x7fffe6a78700 (LWP 12070)]
[New Thread 0x7fffe6277700 (LWP 12071)]
[New Thread 0x7fffe5442700 (LWP 12072)]

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff5ca7cf8 in ?? () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
(gdb) backtrace
#0  0x00007ffff5ca7cf8 in ?? () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#1  0x00007ffff5cb27f6 in QTableView::paintEvent(QPaintEvent*) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#2  0x00007ffff64f54d3 in sipQTableView::paintEvent (this=0xfbfa60, a0=0x7fffffffc0a0) at sipQtGuipart2.cpp:35590
#3  0x00007ffff57be802 in QWidget::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#4  0x00007ffff5b6db66 in QFrame::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#5  0x00007ffff5c7959b in QAbstractItemView::viewportEvent(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#6  0x00007ffff64fbc9b in viewportEvent (a0=0x7fffffffc0a0, this=0xfbfa60) at sipQtGuipart2.cpp:36150
#7  sipQTableView::viewportEvent (this=0xfbfa60, a0=0x7fffffffc0a0) at sipQtGuipart2.cpp:36142
#8  0x00007ffff524a6d6 in QCoreApplicationPrivate::sendThroughObjectEventFilters(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#9  0x00007ffff576ee6c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#10 0x00007ffff577330a in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#11 0x00007ffff67b62a6 in notify (a1=0x7fffffffc0a0, a0=0xe31b10, this=0xcfbcb0) at sipQtGuipart9.cpp:35916
#12 sipQApplication::notify (this=0xcfbcb0, a0=0xe31b10, a1=0x7fffffffc0a0) at sipQtGuipart9.cpp:35908
#13 0x00007ffff524a56e in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#14 0x00007ffff57ba524 in QWidgetPrivate::drawWidget(QPaintDevice*, QRegion const&, QPoint const&, int, QPainter*, QWidgetBackingStore*) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#15 0x00007ffff57bb01f in QWidgetPrivate::paintSiblingsRecursive(QPaintDevice*, QList<QObject*> const&, int, QRegion const&, QPoint const&, int, QPainter*, QWidgetBackingStore*) ()
   from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#16 0x00007ffff57bae64 in QWidgetPrivate::paintSiblingsRecursive(QPaintDevice*, QList<QObject*> const&, int, QRegion const&, QPoint const&, int, QPainter*, QWidgetBackingStore*) ()
   from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#17 0x00007ffff57bae64 in QWidgetPrivate::paintSiblingsRecursive(QPaintDevice*, QList<QObject*> const&, int, QRegion const&, QPoint const&, int, QPainter*, QWidgetBackingStore*) ()
   from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#18 0x00007ffff57bae64 in QWidgetPrivate::paintSiblingsRecursive(QPaintDevice*, QList<QObject*> const&, int, QRegion const&, QPoint const&, int, QPainter*, QWidgetBackingStore*) ()
   from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#19 0x00007ffff57ba0b5 in QWidgetPrivate::drawWidget(QPaintDevice*, QRegion const&, QPoint const&, int, QPainter*, QWidgetBackingStore*) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#20 0x00007ffff5988958 in ?? () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#21 0x00007ffff5988d1e in ?? () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#22 0x00007ffff57eb6aa in ?? () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#23 0x00007ffff57ec6bb in QApplication::x11ProcessEvent(_XEvent*) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#24 0x00007ffff5813fa2 in ?? () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#25 0x00007ffff44b7ab5 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#26 0x00007ffff44b7de8 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#27 0x00007ffff44b7ea4 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#28 0x00007ffff5278bf6 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#29 0x00007ffff5813c1e in ?? () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#30 0x00007ffff52492bf in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#31 0x00007ffff5249548 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#32 0x00007ffff524e708 in QCoreApplication::exec() () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#33 0x00007ffff677762b in meth_QApplication_exec_ (sipArgs=<optimized out>) at sipQtGuipart9.cpp:37856
#34 0x0000000000486b1a in PyCFunction_Call (func=<built-in method exec_ of QApplication object at remote 0xe891e0>, arg=(), kw=0x0) at ../Objects/methodobject.c:81
#35 0x0000000000526610 in call_function (pp_stack=0x7fffffffd960, oparg=0) at ../Python/ceval.c:4021
#36 0x00000000005213fb in PyEval_EvalFrameEx (f=Frame 0xb89c00, for file TestDelegateForRow.py, line 131, in <module> (), throwflag=0) at ../Python/ceval.c:2666
#37 0x0000000000523de9 in PyEval_EvalCodeEx (co=0xcbd510, globals=
    {'choices0': <QStringList at remote 0x10fc2e0>, 'choices1': <QStringList at remote 0x10fc380>, 'app': <QApplication at remote 0xe891e0>, 'delegate0': <ListDelegate(_ListDelegate__colors=<...>) at remote 0xe89420>, 'delegate1': <ListDelegate(_ListDelegate__colors=<...>) at remote 0xe894e0>, 'blue': <QColor at remote 0x10fc240>, 'QtGui': <module at remote 0xcd2a20>, 'data': <QStringList at remote 0x10fc060>, '__package__': None, 'ListDelegate': <PyQt4.QtCore.pyqtWrapperType at remote 0xcfb6a0>, '__doc__': None, 'red': <QColor at remote 0x10fc100>, 'tableView': <QTableView at remote 0xe892a0>, '__builtins__': <module at remote 0x7ffff7fc5470>, '__file__': 'TestDelegateForRow.py', 'sys': <module at remote 0x7ffff7fc55a8>, '__name__': '__main__', 'PaletteListModel': <PyQt4.QtCore.pyqtWrapperType at remote 0xb955b0>, 'green': <QColor at remote 0x10fc1a0>, 'delegate': <ListDelegate(_ListDelegate__colors=<...>) at remote 0xe89660>, 'model': <PaletteListModel(_PaletteListModel__colors=[<...>, <...>, <...>]) at remote ...(truncated), locals=
    {'choices0': <QStringList at remote 0x10fc2e0>, 'choices1': <QStringList at remote 0x10fc380>, 'app': <QApplication at remote 0xe891e0>, 'delegate0': <ListDelegate(_ListDelegate__colors=<...>) at remote 0xe89420>, 'delegate1': <ListDelegate(_ListDelegate__colors=<...>) at remote 0xe894e0>, 'blue': <QColor at remote 0x10fc240>, 'QtGui': <module at remote 0xcd2a20>, 'data': <QStringList at remote 0x10fc060>, '__package__': None, 'ListDelegate': <PyQt4.QtCore.pyqtWrapperType at remote 0xcfb6a0>, '__doc__': None, 'red': <QColor at remote 0x10fc100>, 'tableView': <QTableView at remote 0xe892a0>, '__builtins__': <module at remote 0x7ffff7fc5470>, '__file__': 'TestDelegateForRow.py', 'sys': <module at remote 0x7ffff7fc55a8>, '__name__': '__main__', 'PaletteListModel': <PyQt4.QtCore.pyqtWrapperType at remote 0xb955b0>, 'green': <QColor at remote 0x10fc1a0>, 'delegate': <ListDelegate(_ListDelegate__colors=<...>) at remote 0xe89660>, 'model': <PaletteListModel(_PaletteListModel__colors=[<...>, <...>, <...>]) at remote ...(truncated), args=0x0, argcount=0, kws=0x0, kwcount=0, defs=0x0, defcount=0, closure=0x0) at ../Python/ceval.c:3253
---Type <return> to continue, or q <return> to quit---
#38 0x0000000000519e56 in PyEval_EvalCode (co=0xcbd510, globals=
    {'choices0': <QStringList at remote 0x10fc2e0>, 'choices1': <QStringList at remote 0x10fc380>, 'app': <QApplication at remote 0xe891e0>, 'delegate0': <ListDelegate(_ListDelegate__colors=<...>) at remote 0xe89420>, 'delegate1': <ListDelegate(_ListDelegate__colors=<...>) at remote 0xe894e0>, 'blue': <QColor at remote 0x10fc240>, 'QtGui': <module at remote 0xcd2a20>, 'data': <QStringList at remote 0x10fc060>, '__package__': None, 'ListDelegate': <PyQt4.QtCore.pyqtWrapperType at remote 0xcfb6a0>, '__doc__': None, 'red': <QColor at remote 0x10fc100>, 'tableView': <QTableView at remote 0xe892a0>, '__builtins__': <module at remote 0x7ffff7fc5470>, '__file__': 'TestDelegateForRow.py', 'sys': <module at remote 0x7ffff7fc55a8>, '__name__': '__main__', 'PaletteListModel': <PyQt4.QtCore.pyqtWrapperType at remote 0xb955b0>, 'green': <QColor at remote 0x10fc1a0>, 'delegate': <ListDelegate(_ListDelegate__colors=<...>) at remote 0xe89660>, 'model': <PaletteListModel(_PaletteListModel__colors=[<...>, <...>, <...>]) at remote ...(truncated), locals=
    {'choices0': <QStringList at remote 0x10fc2e0>, 'choices1': <QStringList at remote 0x10fc380>, 'app': <QApplication at remote 0xe891e0>, 'delegate0': <ListDelegate(_ListDelegate__colors=<...>) at remote 0xe89420>, 'delegate1': <ListDelegate(_ListDelegate__colors=<...>) at remote 0xe894e0>, 'blue': <QColor at remote 0x10fc240>, 'QtGui': <module at remote 0xcd2a20>, 'data': <QStringList at remote 0x10fc060>, '__package__': None, 'ListDelegate': <PyQt4.QtCore.pyqtWrapperType at remote 0xcfb6a0>, '__doc__': None, 'red': <QColor at remote 0x10fc100>, 'tableView': <QTableView at remote 0xe892a0>, '__builtins__': <module at remote 0x7ffff7fc5470>, '__file__': 'TestDelegateForRow.py', 'sys': <module at remote 0x7ffff7fc55a8>, '__name__': '__main__', 'PaletteListModel': <PyQt4.QtCore.pyqtWrapperType at remote 0xb955b0>, 'green': <QColor at remote 0x10fc1a0>, 'delegate': <ListDelegate(_ListDelegate__colors=<...>) at remote 0xe89660>, 'model': <PaletteListModel(_PaletteListModel__colors=[<...>, <...>, <...>]) at remote ...(truncated)) at ../Python/ceval.c:667
#39 0x000000000055685c in run_mod (mod=0xb91aa8, filename=0x7fffffffe374 "TestDelegateForRow.py", globals=
    {'choices0': <QStringList at remote 0x10fc2e0>, 'choices1': <QStringList at remote 0x10fc380>, 'app': <QApplication at remote 0xe891e0>, 'delegate0': <ListDelegate(_ListDelegate__colors=<...>) at remote 0xe89420>, 'delegate1': <ListDelegate(_ListDelegate__colors=<...>) at remote 0xe894e0>, 'blue': <QColor at remote 0x10fc240>, 'QtGui': <module at remote 0xcd2a20>, 'data': <QStringList at remote 0x10fc060>, '__package__': None, 'ListDelegate': <PyQt4.QtCore.pyqtWrapperType at remote 0xcfb6a0>, '__doc__': None, 'red': <QColor at remote 0x10fc100>, 'tableView': <QTableView at remote 0xe892a0>, '__builtins__': <module at remote 0x7ffff7fc5470>, '__file__': 'TestDelegateForRow.py', 'sys': <module at remote 0x7ffff7fc55a8>, '__name__': '__main__', 'PaletteListModel': <PyQt4.QtCore.pyqtWrapperType at remote 0xb955b0>, 'green': <QColor at remote 0x10fc1a0>, 'delegate': <ListDelegate(_ListDelegate__colors=<...>) at remote 0xe89660>, 'model': <PaletteListModel(_PaletteListModel__colors=[<...>, <...>, <...>]) at remote ...(truncated), locals=
    {'choices0': <QStringList at remote 0x10fc2e0>, 'choices1': <QStringList at remote 0x10fc380>, 'app': <QApplication at remote 0xe891e0>, 'delegate0': <ListDelegate(_ListDelegate__colors=<...>) at remote 0xe89420>, 'delegate1': <ListDelegate(_ListDelegate__colors=<...>) at remote 0xe894e0>, 'blue': <QColor at remote 0x10fc240>, 'QtGui': <module at remote 0xcd2a20>, 'data': <QStringList at remote 0x10fc060>, '__package__': None, 'ListDelegate': <PyQt4.QtCore.pyqtWrapperType at remote 0xcfb6a0>, '__doc__': None, 'red': <QColor at remote 0x10fc100>, 'tableView': <QTableView at remote 0xe892a0>, '__builtins__': <module at remote 0x7ffff7fc5470>, '__file__': 'TestDelegateForRow.py', 'sys': <module at remote 0x7ffff7fc55a8>, '__name__': '__main__', 'PaletteListModel': <PyQt4.QtCore.pyqtWrapperType at remote 0xb955b0>, 'green': <QColor at remote 0x10fc1a0>, 'delegate': <ListDelegate(_ListDelegate__colors=<...>) at remote 0xe89660>, 'model': <PaletteListModel(_PaletteListModel__colors=[<...>, <...>, <...>]) at remote ...(truncated), flags=0x7fffffffde50, arena=0x9f8ae0) at ../Python/pythonrun.c:1365
#40 0x00000000005567e2 in PyRun_FileExFlags (fp=0xb3e1b0, filename=0x7fffffffe374 "TestDelegateForRow.py", start=257, globals=
    {'choices0': <QStringList at remote 0x10fc2e0>, 'choices1': <QStringList at remote 0x10fc380>, 'app': <QApplication at remote 0xe891e0>, 'delegate0': <ListDelegate(_ListDelegate__colors=<...>) at remote 0xe89420>, 'delegate1': <ListDelegate(_ListDelegate__colors=<...>) at remote 0xe894e0>, 'blue': <QColor at remote 0x10fc240>, 'QtGui': <module at remote 0xcd2a20>, 'data': <QStringList at remote 0x10fc060>, '__package__': None, 'ListDelegate': <PyQt4.QtCore.pyqtWrapperType at remote 0xcfb6a0>, '__doc__': None, 'red': <QColor at remote 0x10fc100>, 'tableView': <QTableView at remote 0xe892a0>, '__builtins__': <module at remote 0x7ffff7fc5470>, '__file__': 'TestDelegateForRow.py', 'sys': <module at remote 0x7ffff7fc55a8>, '__name__': '__main__', 'PaletteListModel': <PyQt4.QtCore.pyqtWrapperType at remote 0xb955b0>, 'green': <QColor at remote 0x10fc1a0>, 'delegate': <ListDelegate(_ListDelegate__colors=<...>) at remote 0xe89660>, 'model': <PaletteListModel(_PaletteListModel__colors=[<...>, <...>, <...>]) at remote ...(truncated), locals=
    {'choices0': <QStringList at remote 0x10fc2e0>, 'choices1': <QStringList at remote 0x10fc380>, 'app': <QApplication at remote 0xe891e0>, 'delegate0': <ListDelegate(_ListDelegate__colors=<...>) at remote 0xe89420>, 'delegate1': <ListDelegate(_ListDelegate__colors=<...>) at remote 0xe894e0>, 'blue': <QColor at remote 0x10fc240>, 'QtGui': <module at remote 0xcd2a20>, 'data': <QStringList at remote 0x10fc060>, '__package__': None, 'ListDelegate': <PyQt4.QtCore.pyqtWrapperType at remote 0xcfb6a0>, '__doc__': None, 'red': <QColor at remote 0x10fc100>, 'tableView': <QTableView at remote 0xe892a0>, '__builtins__': <module at remote 0x7ffff7fc5470>, '__file__': 'TestDelegateForRow.py', 'sys': <module at remote 0x7ffff7fc55a8>, '__name__': '__main__', 'PaletteListModel': <PyQt4.QtCore.pyqtWrapperType at remote 0xb955b0>, 'green': <QColor at remote 0x10fc1a0>, 'delegate': <ListDelegate(_ListDelegate__colors=<...>) at remote 0xe89660>, 'model': <PaletteListModel(_PaletteListModel__colors=[<...>, <...>, <...>]) at remote ...(truncated), closeit=1, flags=0x7fffffffde50) at ../Python/pythonrun.c:1351
#41 0x0000000000555002 in PyRun_SimpleFileExFlags (fp=0xb3e1b0, filename=0x7fffffffe374 "TestDelegateForRow.py", closeit=1, flags=0x7fffffffde50) at ../Python/pythonrun.c:943
#42 0x00000000005546b5 in PyRun_AnyFileExFlags (fp=0xb3e1b0, filename=0x7fffffffe374 "TestDelegateForRow.py", closeit=1, flags=0x7fffffffde50) at ../Python/pythonrun.c:747
#43 0x0000000000570290 in Py_Main (argc=2, argv=0x7fffffffe068) at ../Modules/main.c:639
#44 0x00000000004171fc in main (argc=2, argv=0x7fffffffe068) at ../Modules/python.c:23
(gdb) ^Z

Of course, any help or guidance would be greatly appreciated.

Answer 1

The Qt documentation for setItemDelegateForRow is pretty clear on this:

Any existing row delegate for row will be removed, but not deleted.
QAbstractItemView does not take ownership of delegate.

So you've already diagnosed your problem, but not followed through on it.

The segfaults are occuring because some of the delegates are being garbage-collected before the table-view is initialized.

Try creating a table-view subclass which keeps an internal list of its delegates:

...    

class TableView(QtGui.QTableView):
    def __init__(self):
        QtGui.QTableView.__init__(self)
        colours = [
            QtGui.QColor(255,0,0),
            QtGui.QColor(0,255,0),
            QtGui.QColor(0,0,255),
            ]
        self._delegates = [
            ListDelegate(["#FF0000","#00FF00","#0000FF"]),
            ListDelegate(["#FF0000","#0000FF"]),
            ]
        for row in range(len(colours)):
            self.setItemDelegateForRow(
                row, self._delegates[bool(row % 2)])
        self.setModel(PaletteListModel(colours))

if __name__ == '__main__':

    app = QtGui.QApplication(sys.argv)
    app.setStyle("plastique")

    table = TableView()
    table.show()

    sys.exit(app.exec_())