ctypes.CDLL on Linux creates a "main program" object when passed an empty string

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Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
46/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
python
Domain
operating-systems

Research direction

Start by running the reported ctypes.CDLL('') reproducer on Linux and compare it with a missing library name. Trace the ctypes.CDLL loading path and make the empty-string case raise an exception rather than create a dummy object; done when that behavior is covered by a regression test.

Written by the indexing model from the issue text.

Description

docs topic-ctypes

Bug report

ctypes.CDLL throws an exception when it can't find a library in the path pointed at by its name argument; however, if name is an empty string a dummy object is created:

>>> import ctypes
>>> ctypes.CDLL('')
<CDLL '', handle 7fb30d2d3190 at 0x7fb30c2caa60>

I don't think this is correct, since that dummy object will break things when trying to use it later on.

Your environment

  • CPython versions tested on: 3.8.10, 3.10.8
  • Operating system and architecture: Ubuntu 20.04.5 LTS for x86_64

This doesn't happen on Windows with Python 3.10.7; there I see an exception being thrown for the empty string.

Dominant language
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