def _safe_lock_release_py2(rlock):
  """Ensure that a threading.RLock is fully released for Python 2.

  The RLock release code is:
    https://github.com/python/cpython/blob/2.7/Lib/threading.py#L187

  The RLock object's release method does not release all of its state if an
  exception is raised in the middle of its operation.  There are three pieces of
  internal state that must be cleaned up:
  - owning thread ident, an integer.
  - entry count, an integer that counts how many times the current owner has
      locked the RLock.
  - internal lock, a threading.Lock instance that handles blocking.

  Args:
    rlock: threading.RLock, lock to fully release.

  Yields:
    None.
  """
  assert isinstance(rlock, threading._RLock)
  ident = _thread.get_ident()
  expected_count = 0
  if rlock._RLock__owner == ident:
    expected_count = rlock._RLock__count
  try:
    yield
  except ThreadTerminationError:
    # Check if the current thread still owns the lock by checking if we can
    # acquire the underlying lock.
    if rlock._RLock__block.acquire(0):
      # Lock is clean, so unlock and we are done.
      rlock._RLock__block.release()
    elif rlock._RLock__owner == ident and expected_count > 0:
      # The lock is still held up the stack, so make sure the count is accurate.
      if rlock._RLock__count != expected_count:
        rlock._RLock__count = expected_count
    elif rlock._RLock__owner == ident or rlock._RLock__owner is None:
      # The internal lock is still acquired, but either this thread or no thread
      # owns it, which means it needs to be hard reset.
      rlock._RLock__owner = None
      rlock._RLock__count = 0
      rlock._RLock__block.release()
    raise
Ensure that a threading.RLock is fully released for Python 2.

  The RLock release code is:
    https://github.com/python/cpython/blob/2.7/Lib/threading.py#L187

  The RLock object's release method does not release all of its state if an
  exception is raised in the middle of its operation.  There are three pieces of
  internal state that must be cleaned up:
  - owning thread ident, an integer.
  - entry count, an integer that counts how many times the current owner has
      locked the RLock.
  - internal lock, a threading.Lock instance that handles blocking.

  Args:
    rlock: threading.RLock, lock to fully release.

  Yields:
    None.