Fixed traceback from CompletionWidget when hideEvent is received when the widget is not visible

IPython/frontend/qt/console/completion_widget.py

@@ -1,121 +1,124 b''
 # System library imports
 from PyQt4 import QtCore, QtGui
 
 
 class CompletionWidget(QtGui.QListWidget):
     """ A widget for GUI tab completion.
     """
 
     #--------------------------------------------------------------------------
     # 'QWidget' interface
     #--------------------------------------------------------------------------
 
     def __init__(self, parent):
         """ Create a completion widget that is attached to the specified Qt
             text edit widget.
         """
         assert isinstance(parent, (QtGui.QTextEdit, QtGui.QPlainTextEdit))
         QtGui.QListWidget.__init__(self, parent)
 
         self.setWindowFlags(QtCore.Qt.ToolTip | QtCore.Qt.WindowStaysOnTopHint)
         self.setAttribute(QtCore.Qt.WA_StaticContents)
 
         # Ensure that parent keeps focus when widget is displayed.
         self.setFocusProxy(parent)
 
         self.setFrameShadow(QtGui.QFrame.Plain)
         self.setFrameShape(QtGui.QFrame.StyledPanel)
 
         self.itemActivated.connect(self._complete_current)
 
     def hideEvent(self, event):
         """ Reimplemented to disconnect the cursor movement handler.
         """
         QtGui.QListWidget.hideEvent(self, event)
-        self.parent().cursorPositionChanged.disconnect(self._update_current)
+        try:
+            self.parent().cursorPositionChanged.disconnect(self._update_current)
+        except TypeError:
+            pass
         
     def keyPressEvent(self, event):
         """ Reimplemented to update the list.
         """
         key, text = event.key(), event.text()
 
         if key in (QtCore.Qt.Key_Return, QtCore.Qt.Key_Enter, 
                    QtCore.Qt.Key_Tab):
             self._complete_current()
             event.accept()
 
         elif key == QtCore.Qt.Key_Escape:
             self.hide()
             event.accept()
 
         elif key in (QtCore.Qt.Key_Up, QtCore.Qt.Key_Down, 
                      QtCore.Qt.Key_PageUp, QtCore.Qt.Key_PageDown, 
                      QtCore.Qt.Key_Home, QtCore.Qt.Key_End):
             QtGui.QListWidget.keyPressEvent(self, event)
             event.accept()
 
         else:
             event.ignore()
 
     def showEvent(self, event):
         """ Reimplemented to connect the cursor movement handler.
         """
         QtGui.QListWidget.showEvent(self, event)
         self.parent().cursorPositionChanged.connect(self._update_current)
 
     #--------------------------------------------------------------------------
     # 'CompletionWidget' interface
     #--------------------------------------------------------------------------
 
     def show_items(self, cursor, items):
         """ Shows the completion widget with 'items' at the position specified
             by 'cursor'.
         """
         text_edit = self.parent()
         point = text_edit.cursorRect(cursor).bottomRight()
         point = text_edit.mapToGlobal(point)
         screen_rect = QtGui.QApplication.desktop().availableGeometry(self)
         if screen_rect.size().height() - point.y() - self.height() < 0:
             point = text_edit.mapToGlobal(text_edit.cursorRect().topRight())
             point.setY(point.y() - self.height())
         self.move(point)
 
         self._start_position = cursor.position()
         self.clear()
         self.addItems(items)
         self.setCurrentRow(0)
         self.show()
 
     #--------------------------------------------------------------------------
     # Protected interface
     #--------------------------------------------------------------------------
 
     def _complete_current(self):
         """ Perform the completion with the currently selected item.
         """
         self._current_text_cursor().insertText(self.currentItem().text())
         self.hide()
 
     def _current_text_cursor(self):
         """ Returns a cursor with text between the start position and the
             current position selected.
         """
         cursor = self.parent().textCursor()
         if cursor.position() >= self._start_position:
             cursor.setPosition(self._start_position, 
                                QtGui.QTextCursor.KeepAnchor)
         return cursor
         
     def _update_current(self):
         """ Updates the current item based on the current text.
         """
         prefix = self._current_text_cursor().selectedText()
         if prefix:
             items = self.findItems(prefix, (QtCore.Qt.MatchStartsWith | 
                                             QtCore.Qt.MatchCaseSensitive))
             if items:
                 self.setCurrentItem(items[0])
             else:
                 self.hide()
         else:
             self.hide()