import traceback


def make_with_lambda():
  limit = 1024
  loop = "fake_loop"
  protocol_factory = lambda: SubprocessStreamProtocol(limit=limit, loop=loop)
  return protocol_factory


def make_with_def():
  limit = 1024
  loop = "fake_loop"

  def protocol_factory():
      return SubprocessStreamProtocol(limit=limit, loop=loop)

  return protocol_factory


class SubprocessStreamProtocol:
  def __init__(self, limit, loop):
      raise RuntimeError("simulated init failure")


def show(label, factory):
  print(f"=== {label} ===")
  print(f"  __name__     = {factory.__name__!r}")
  print(f"  __qualname__ = {factory.__qualname__!r}")
  print(f"  repr         = {factory!r}")
  print()
  print("  Traceback when factory raises:")
  try:
      factory()
  except RuntimeError:
      tb = traceback.format_exc()
      for line in tb.splitlines():
          print(f"    {line}")
  print()


show("lambda-traceback", make_with_lambda())
show("def-traceback", make_with_def())