UnboundLocalError in overloading.py

[Tom Henderson]

building ns-3-dev with python bindings enabled (changeset 04ef86d43986) yields the following error in build/src/lte/bindings/ns3modulegen.log

Traceback (most recent call last):
  File "bindings/python/ns3modulegen-modular.py", line 125, in <module>
    main(sys.argv)
  File "bindings/python/ns3modulegen-modular.py", line 121, in main
    root_module.generate(out)
  File "/a/users/tomh/ns-3-allinone/pybindgen/pybindgen/module.py", line 894, in generate
    self.do_generate(sink_manager, module_file_base_name)
  File "/a/users/tomh/ns-3-allinone/pybindgen/pybindgen/module.py", line 761, in do_generate
    class_.generate(sink, self)
  File "/a/users/tomh/ns-3-allinone/pybindgen/pybindgen/cppclass.py", line 2029, in generate
    self._generate_methods(code_sink, parent_caller_methods)
  File "/a/users/tomh/ns-3-allinone/pybindgen/pybindgen/cppclass.py", line 2412, in _generate_methods
    utils.call_with_error_handling(overload.generate, (code_sink,), {}, overload)
  File "/a/users/tomh/ns-3-allinone/pybindgen/pybindgen/utils.py", line 147, in call_with_error_handling
    return callback(*args, **kwargs)
  File "/a/users/tomh/ns-3-allinone/pybindgen/pybindgen/overloading.py", line 131, in generate
    self._normalize_py_method_flags()
  File "/a/users/tomh/ns-3-allinone/pybindgen/pybindgen/overloading.py", line 114, in _normalize_py_method_flags
    settings.error_handler.handle_error(wrapper, ex, tb)
UnboundLocalError: local variable 'ex' referenced before assignment

I worked around this with a small hack:

=== modified file 'pybindgen/overloading.py'
--- pybindgen/overloading.py 2009-09-16 12:06:59 +0000
+++ pybindgen/overloading.py 2013-08-01 16:06:39 +0000
@@ -111,6 +111,7 @@
                         modified = True
                         self.wrappers.remove(wrapper)
                         tb = traceback.extract_stack()
+ ex = 'none'
                         settings.error_handler.handle_error(wrapper, ex, tb)
                         break

I could not easily determine what has changed in the lte bindings to force this error, but the above workaround lets me build ns-3 and run all python tests successfully.