无法获取Python函数源代码：咨询是否需重装及环境排查

问题说明 #

无法通过inspect.getsource()获取函数源代码，报错OSError: could not get source code，且使用marvin库的@ai_fn装饰器时也出现相同错误。涉及环境为conda-forge打包的Python 3.7.6（Linux）及Python 3.10。

交互式定义函数报错示例 #

# python
Python 3.7.6 | packaged by conda-forge | (default, Mar 23 2020, 22:25:07)
[GCC 7.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> def foo(arg1,arg2):
...     #do something with args
...     a = arg1 + arg2
...     return a
...
>>> import inspect
>>> lines = inspect.getsource(foo)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/root/miniforge3/lib/python3.7/inspect.py", line 973, in getsource
    lines, lnum = getsourcelines(object)
  File "/root/miniforge3/lib/python3.7/inspect.py", line 955, in getsourcelines
    lines, lnum = findsource(object)
  File "/root/miniforge3/lib/python3.7/inspect.py", line 786, in findsource
    raise OSError('could not get source code')
OSError: could not get source code

使用marvin装饰器报错示例 #

>>> from marvin import ai_fn
>>> @ai_fn
... @ai_fn
... def rhyme(word: str) -> str:
...     "Returns a word that rhymes with the input word."
...
>>> rhyme("blue")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python3.10/site-packages/marvin/bots/ai_functions.py", line 128, in ai_fn_wrapper
    return_value = fn(*args, **kwargs)
  File "/usr/local/lib/python3.10/site-packages/marvin/bots/ai_functions.py", line 141, in ai_fn_wrapper
    function_def = inspect.cleandoc(inspect.getsource(fn))
  File "/usr/local/lib/python3.10/inspect.py", line 1139, in getsource
    lines, lnum = getsourcelines(object)
  File "/usr/local/lib/python3.10/inspect.py", line 1121, in getsourcelines
    lines, lnum = findsource(object)
  File "/usr/local/lib/python3.10/inspect.py", line 958, in findsource
    raise OSError('could not get source code')
OSError: could not get source code

原因分析 #

1. inspect.getsource()依赖磁盘上的物理源文件读取函数代码，而Python交互式命令行（stdin）中定义的函数仅存在于内存中，没有对应的源文件，因此无法被inspect模块定位。
2. marvin库的@ai_fn装饰器内部调用了inspect.getsource()，当装饰的函数是在交互式环境中定义时，同样会触发上述错误。

结论与解决方案 #

• 无需重装Python，当前Python环境完全正常，该报错是inspect模块的预期行为，而非环境损坏。
• 解决方案：
  • 将需要获取源代码的函数写入.py文件，而非在交互式命令行中定义。
  • 运行该.py文件或在文件内调用inspect.getsource()，即可正常获取函数源代码。
  • 使用marvin的@ai_fn装饰器时，需将装饰的函数放在.py文件中执行，避免使用交互式环境。

内容的提问来源于stack exchange，提问作者shantanuo