Fixes bug #502.

The ownership of the editor returned by the Python override of
QAbstractItemDelegate.createEditor(...) is now transferred to C++.

A test was added to simulate the situation that triggers the bug,
instead of relying on an example with a view, model and editable cells.

See: http://bugs.openbossa.org/show_bug.cgi?id=502

Reviewed by Lauro Moura <lauro.neto@openbossa.org>
Reviewed by Renato Araújo <renato.filho@openbossa.org>

tests/pysidetest/delegatecreateseditor_test.py

@@ -0,0 +1,55 @@
+#!/usr/bin/python
+
+import unittest
+from helper import UsesQApplication
+
+from testbinding import TestView
+from PySide.QtCore import Qt
+from PySide.QtGui import QAbstractItemDelegate, QComboBox
+
+id_text = 'This is me'
+
+class DelegateDoesntKeepReferenceToEditor(QAbstractItemDelegate):
+    def createEditor(self, parent, option, index):
+        comboBox = QComboBox(parent)
+        comboBox.addItem(id_text)
+        return comboBox
+
+
+class DelegateKeepsReferenceToEditor(QAbstractItemDelegate):
+    def __init__(self, parent=None):
+        QAbstractItemDelegate.__init__(self, parent)
+        self.comboBox = QComboBox()
+        self.comboBox.addItem(id_text)
+
+    def createEditor(self, parent, option, index):
+        self.comboBox.setParent(parent)
+        return self.comboBox
+
+
+class EditorCreatedByDelegateTest(UsesQApplication):
+
+    def testDelegateDoesntKeepReferenceToEditor(self):
+        view = TestView(None)
+        delegate = DelegateDoesntKeepReferenceToEditor()
+        view.setItemDelegate(delegate)
+        editor = view.getEditorWidgetFromItemDelegate()
+        self.assertEqual(type(editor), QComboBox)
+        self.assertEqual(editor.count(), 1)
+        self.assertEqual(editor.itemData(0, Qt.DisplayRole), id_text)
+        editor.metaObject()
+
+    def testDelegateKeepsReferenceToEditor(self):
+        view = TestView(None)
+        delegate = DelegateKeepsReferenceToEditor()
+        view.setItemDelegate(delegate)
+        editor = view.getEditorWidgetFromItemDelegate()
+        self.assertEqual(type(editor), QComboBox)
+        self.assertEqual(editor.count(), 1)
+        self.assertEqual(editor.itemData(0, Qt.DisplayRole), id_text)
+        editor.metaObject()
+
+
+if __name__ == '__main__':
+    unittest.main()
+