Is it possible to decompile a .dll/.pyd file to extract Python Source Code?

Question

Are there any ways to decompile a dll and/or a .pyd file in order to extract source code written in Python?

Thanks in advance

Answer 1

I don't agree with the accepted answer, it seems that yes, the content of the source code is accessible even in a .pyd.

Let's see for example what happens if an error arrives:

1) Create this file:

whathappenswhenerror.pyx

A = 6 
print 'hello'
print A
print 1/0 # this will generate an error

2) Compile it with python setup.py build:

setup.py

from distutils.core import setup
from Cython.Build import cythonize
setup(ext_modules = cythonize("whathappenswhenerror.pyx"), include_dirs=[])

3) Now import the .pyd file in a standard python file:

testwhathappenswhenerror.py

import whathappenswhenerror

4) Let's run it with python testwhathappenswhenerror.py. Here is the output:

hello 
6 
Traceback (most recent call last):
  File "D:\testwhathappenswhenerror.py", line 1, in 
    import whathappenswhenerror
  File "whathappenswhenerror.pyx", line 4, in init whathappenswhenerror (whathappenswhenerror.c:824)
    print 1/0 # this will generate an error 
ZeroDivisionError: integer division or modulo by zero

As you can see the line of code print 1/0 # this will generate an error that was in the .pyx source code is displayed! Even the comment is displayed!

4 bis) If I delete (or move somewhere else) the original .pyx file before step 3), then the original code print 1/0 # this will generate an error is no longer displayed:

hello
6
Traceback (most recent call last):
  File "D:\testwhathappenswhenerror.py", line 1, in 
    import whathappenswhenerror
  File "whathappenswhenerror.pyx", line 4, in init whathappenswhenerror (whathappenswhenerror.c:824)
ZeroDivisionError: integer division or modulo by zero

But does this mean it's not included in the .pyd? I'm not sure.