python npm-bazel-gen.py hangs

[pcj]

I get a bunch of these stack traces when trying to get started:

$ python npm-bazel-gen.py

...

Exception in thread Thread-16:
Traceback (most recent call last):
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/threading.py", line 808, in __bootstrap_inner
    self.run()
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/threading.py", line 761, in run
    self.__target(*self.__args, **self.__kwargs)
  File "npm-bazel-gen.py", line 125, in worker
    for name, version in get_dependencies(parent_name, resolved_parent_version).viewitems():
  File "npm-bazel-gen.py", line 74, in get_dependencies
    output = json.loads(result_string)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/__init__.py", line 338, in loads
    return _default_decoder.decode(s)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/decoder.py", line 365, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/decoder.py", line 383, in raw_decode
    raise ValueError("No JSON object could be decoded")
Exception: error reading dependencies for [email protected]: <
>
Caused by: ValueError: No JSON object could be decoded

Looks like if exception is thrown by get_dependencies, q.task_done() not called and q.join() can't pass.