From 409be8336f4c597bcca9d9eaa09df0abc065afff Mon Sep 17 00:00:00 2001 From: Wenzel Jakob Date: Fri, 24 Sep 2021 13:03:57 +0200 Subject: [PATCH] CMake: react to python version changes The new FindPython-based variant of the CMake scripts caches information about the chosen Python version that can become stale. For example, suppose I configure a simple pybind11-based project as follows ``` cmake -S . -B build -GNinja -DPython_ROOT= ``` which will generate `my_extension.cpython-38-x86_64-linux-gnu.so`. A subsequent change to the python version like ``` cmake -S . -B build -GNinja -DPython_ROOT= ``` does not update all necessary build system information. In particular, the compiled file is still called `my_extension.cpython-38-x86_64-linux-gnu.so`. This commit fixes the problem by detecting changes in `Python_EXECUTABLE` and re-running Python as needed. Note that the previous way of detecting Python does not seem to be affected, it always specifies the right suffix. --- tools/pybind11NewTools.cmake | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/tools/pybind11NewTools.cmake b/tools/pybind11NewTools.cmake index a20803bc..b93f9145 100644 --- a/tools/pybind11NewTools.cmake +++ b/tools/pybind11NewTools.cmake @@ -82,6 +82,15 @@ if(NOT DEFINED ${_Python}_EXECUTABLE) endif() +if(NOT ${_Python}_EXECUTABLE STREQUAL PYTHON_EXECUTABLE_LAST) + # Detect changes to the Python version/binary in subsequent CMake runs, and refresh config if needed + unset(PYTHON_IS_DEBUG CACHE) + unset(PYTHON_MODULE_EXTENSION CACHE) + set(PYTHON_EXECUTABLE_LAST + "${${_Python}_EXECUTABLE}" + CACHE INTERNAL "Python executable during the last CMake run") +endif() + if(NOT DEFINED PYTHON_IS_DEBUG) # Debug check - see https://stackoverflow.com/questions/646518/python-how-to-detect-debug-Interpreter execute_process(