CODEWITHSUNDEEP
pythonc++cmakepybind11
Alexander Soare
Alexander Soare

Reputation: 3257

Python version mismatch even though CMake reports having found the correct version

I'm building some C++ Python extensions for Python 3.10 (using PyBind11) but I'm finding that when trying to import these extensions I get: ImportError: Python version mismatch: module was compiled for Python 3.8, but the interpreter version is incompatible: 3.10.5.

I have find_package(Python3 3.10 REQUIRED) in my CMakeLists.txt and I use -DPYTHON_EXECUTABLE:FILEPATH=$(which python) when running cmake. I can confirm that which python points to a Python 3.10 executable. When running cmake part of the output says:

Found Python3: /PATH/TO/venv/bin/python3 (found suitable version "3.10.5", minimum required is "3.10") found components: Interpreter

and there are no other mentions of finding some other Python version. The compiled files look like module.cpython-310-x86_64-linux-gnu.so. Because of the 310 they can only be imported into a Python 3.10 interpreter sesion.

BUT, when I try importing them I get the ImportError I mentioned above. On the other hand, if I manually rename the compiled files to module.cpython-38-x86_64-linux-gnu.so and open up a Python 3.8 interpreter, I'm able to import.

How can I fix this? Why are all the clues suggesting that I have built the files correctly when I somehow haven't?

Note that I have already tried the solutions from the answers here.

Upvotes: 3

Views: 1644

Answers (1)

Alexander Soare
Alexander Soare

Reputation: 3257

There may have been other factors at play here (like including 3rd party CMake projects) so to fix my problem the first step was to remove those. Then I:

  • changed my find_package(Python3 3.10 REQUIRED) to find_package(Python3 3.10 REQUIRED COMPONENTS Interpreter Development) (see here). User @Tsyvarev also somewhat alluded to this in his comment on my question.
  • installed sudo apt install python3.10-dev (I only had this for Python 3.8). If you're like me and don't understand the difference between sudo apt install python and sudo apt install python-dev see this answer.

Upvotes: 2

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