在Python 3.4中使用runpy时未显示回溯

Question

通过runpy运行Python模块有时不会显示任何回溯。

例如，如果模块引发一个AttributeError，那么结果将是这样；

$ echo 'import random; random.dsgjdgj' > hello/__init__.py
$ python -m hello
/bin/python: Error while finding spec for 'hello.__main__' 
(<class 'AttributeError'>: 'module' object has no attribute 'dsgjdgj');
'hello' is a package and cannot be directly executed

但是，如果您引发了NameError，回溯将正确显示；

$ echo 'lalalalal' > hello/__init__.py
$ python -m hello
Traceback (most recent call last):
  File "/usr/lib/python3.4/runpy.py", line 151, in _run_module_as_main
    mod_name, mod_spec, code = _get_module_details(mod_name)
  File "/usr/lib/python3.4/runpy.py", line 118, in _get_module_details
    return _get_module_details(pkg_main_name)
  File "/usr/lib/python3.4/runpy.py", line 104, in _get_module_details
    spec = importlib.util.find_spec(mod_name)
  File "/usr/lib/python3.4/importlib/util.py", line 86, in find_spec
    parent = __import__(parent_name, fromlist=['__path__'])
  File "/vagrant/server/hello/__init__.py", line 1, in <module>
    lalalalal
NameError: name 'lalalalal' is not defined

我想要显示一个完整的回溯，不管错误是什么。我尝试了几个命令行界面选项，包括-v -d，但没有任何影响。

它似乎与这个cpython/Lib/runpy.py有关

try:
    spec = importlib.util.find_spec(mod_name)
except (ImportError, AttributeError, TypeError, ValueError) as ex:
    # This hack fixes an impedance mismatch between pkgutil and
    # importlib, where the latter raises other errors for cases where
    # pkgutil previously raised ImportError
    msg = "Error while finding spec for {!r} ({}: {})"
    raise ImportError(msg.format(mod_name, type(ex), ex)) from ex

据我所知，from ex应该确保原始的回溯保持得当，并在某个阶段通过标准输出打印出来。

问题的根源似乎是；

except ImportError as exc:
    # Try to provide a good error message
    # for directories, zip files and the -m switch
    if alter_argv:
        # For -m switch, just display the exception
        info = str(exc)

有什么想法吗？

Answer 1

这是Python中的一个潜在错误，已在here中提出。