Python 3.5 调试启动错误
我尝试使用 Visual Studio 2005 在调试模式下启动一个小型 Python 程序。但它无法到达第一个语句，即import语句。为什么会__file__出现如下所述的错误？
一个名为 Swap.py 的 Quantlib 示例在 Visual Studio 2015 中以发布模式运行而没有错误。但在调试模式下，它会在启动时出现此错误：
Additional information: 'module' object has no attribute '__file__'
Quantlib 版本是 1.6.2，QuantLib SWIG 版本是 1.6.1。
这是 swap.py 的第一行，但并没有那么远：
from QuantLib import *
我安装了 Python 3.5 调试组件。
然后在 Visual Studio 2015 for Python 中，我创建了一个 Python 环境来使用 python_d.exe、pythonw_d.exe 和 python35_d.dll。
输出窗口：
'python_d.exe' (Win32): Loaded 'C:\Program Files (x86)\Python 3.5\python_d.exe'. Symbols loaded.
'python_d.exe' (Win32): Loaded 'C:\Windows\SysWOW64\ntdll.dll'. Cannot find or open the PDB file.
'python_d.exe' (Win32): Loaded 'C:\Windows\SysWOW64\kernel32.dll'. Cannot find or open the PDB file.
'python_d.exe' (Win32): Loaded 'C:\Windows\SysWOW64\KernelBase.dll'. Cannot find or open the PDB file.
'python_d.exe' (Win32): Loaded 'C:\Program Files (x86)\Python 3.5\python35_d.dll'. Symbols loaded.
'python_d.exe' (Win32): Loaded 'C:\Windows\SysWOW64\vcruntime140d.dll'. Cannot find or open the PDB file.
'python_d.exe' (Win32): Loaded 'C:\Windows\SysWOW64\ucrtbased.dll'. Cannot find or open the PDB file.
'python_d.exe' (Win32): Loaded 'C:\Windows\SysWOW64\ws2_32.dll'. Cannot find or open the PDB file. <frozen importlib._bootstrap>!_spec_from_module Line 483 Python
<frozen importlib._bootstrap>!_setup Line 1107 Python
<frozen importlib._bootstrap>!_install Line 1134 Python
[External Code]
python_d.exe!wmain(int argc, wchar_t * * argv) Line 14 C
[External Code]
'python_d.exe' (Win32): Loaded 'C:\Windows\SysWOW64\advapi32.dll'. Cannot find or open the PDB file.
'python_d.exe' (Win32): Loaded 'C:\Windows\SysWOW64\nsi.dll'. Cannot find or open the PDB file.
'python_d.exe' (Win32): Loaded 'C:\Windows\SysWOW64\rpcrt4.dll'. Cannot find or open the PDB file.
'python_d.exe' (Win32): Loaded 'C:\Windows\SysWOW64\msvcrt.dll'. Cannot find or open the PDB file.
'python_d.exe' (Win32): Loaded 'C:\Windows\SysWOW64\sechost.dll'. Cannot find or open the PDB file.
'python_d.exe' (Win32): Loaded 'C:\Windows\SysWOW64\sspicli.dll'. Cannot find or open the PDB file.
'python_d.exe' (Win32): Loaded 'C:\Windows\SysWOW64\cryptbase.dll'. Cannot find or open the PDB file.
'python_d.exe' (Win32): Loaded 'C:\Windows\SysWOW64\bcryptprimitives.dll'. Cannot find or open the PDB file.
'python_d.exe' (Win32): Loaded 'C:\Windows\SysWOW64\cryptsp.dll'. Cannot find or open the PDB file.
'python_d.exe' (Win32): Loaded 'D:\ProgramFiles\vc2015\Common7\IDE\Extensions\Microsoft\Python Tools for Visual Studio\2.2\Microsoft.PythonTools.Debugger.Helper.x86.dll'. Symbols loaded.
'python_d.exe' (Python): Loaded ''. Module was built without symbols.
The thread 0x26d4 has exited with code 1577189376 (0x5e020000).
'python_d.exe' (Win32): Loaded 'C:\Windows\SysWOW64\rsaenh.dll'. Cannot find or open the PDB file.
'python_d.exe' (Win32): Loaded 'C:\Windows\SysWOW64\bcrypt.dll'. Cannot find or open the PDB file.
'python_d.exe' (Python): Loaded '<frozen importlib._bootstrap>'. Module was built without symbols.
AttributeError
Additional information: 'module' object has no attribute '__file__'
堆栈：
<frozen importlib._bootstrap>!_spec_from_module Line 483 Python
<frozen importlib._bootstrap>!_setup Line 1107 Python
<frozen importlib._bootstrap>!_install Line 1134 Python
[External Code]
python_d.exe!wmain(int argc, wchar_t * * argv) Line 14 C
[External Code]
我能够调试 Python 代码（至少查看 Visual Studio Locals）。我们需要能够在 Python 和本机代码中进行调试。这是失败后堆栈的样子：
这是失败的 Python 函数（代码为失败点）：
def _spec_from_module(module, loader=None, origin=None):
# This function is meant for use in _setup().
try:
spec = module.__spec__
except AttributeError:
pass
else:
if spec is not None:
return spec
name = module.__name__
if loader is None:
try:
loader = module.__loader__
except AttributeError:
# loader will stay None.
pass
try:
location = module.__file__
但是__file__模块中没有字段：
loader 对象有很多字段，下面是其中的一些：
loader has type class BuiltinImporter
loader.__module__'_frozen_importlib' str
loader.__mro__ (<class 'BuiltinImporter'>, <class 'object'>) tuple