Fixed line_number being inserted as a string into the %edit payload.

IPython/frontend/qt/console/ipython_widget.py

@@ -25,7 +25,7 b' class IPythonWidget(FrontendWidget):'
 
     # Signal emitted when an editor is needed for a file and the editor has been
     # specified as 'custom'. See 'set_editor' for more information.
-    custom_edit_requested = QtCore.pyqtSignal(object, int)
+    custom_edit_requested = QtCore.pyqtSignal(object, object)
 
     # The default stylesheet: black text on a white background.
     default_stylesheet = """

IPython/zmq/zmqshell.py

@@ -246,6 +246,12 b' class ZMQInteractiveShell(InteractiveShell):'
         
         # Default line number value
         lineno = opts.get('n',None)
+        if lineno is not None:
+            try:
+                lineno = int(lineno)
+            except:
+                warn("The -n argument must be an integer.")
+                return
 
         if opts_p:
             args = '_%s' % last_call[0]