PYTHON_SITE_PACKAGES_DIR is not honored about libarcus

[ForceFaction]

I see. Your argument makes perfect sense and i agree.

I will search how to influence FIndPython3 then.

Thank you for your time :)

[ForceFaction]

commit 724d8f6 seems to have removed that option from the CMakeLists.txt.

I should add i'm trying to build 4.7.1 :)

[Ghostkeeper]

Yup, you're right. It seems that functionality was removed then to fix an issue with the CMake version we're running on our CentOS build server. I'll remove it from the documentation.

[ForceFaction]

That's unfortunate. I'm trying to package this library for Guix and i get a permission denied error because the package tries to install files outside of it's CMAKE_INSTALL_PREFIX'ed path. Build log is attached. If you have questions regarding the build log and what different things mean, please ask :-)

log.txt

[Ghostkeeper]

Hmm, yeah I guess that could happen due to the installation directive at

libArcus/cmake/SIPMacros.cmake

Line 131 in 3925125

INSTALL(TARGETS ${_logical_name} DESTINATION "${Python3_SITEARCH}/${_parent_module_path}")

Could you try adjusting Python3_SITEARCH?

[ForceFaction]

Setting this variable with -DPython3_SITEARCH doesn't make a difference. Even hardcoding doesn't seem to help.

[ForceFaction]

I see, no wonder it doesn't work i'm using CMake 3.16 that means the line you mentioned doesn't get executed here, so changes there make no sense.

EDIT: I also see that this is different on master ... I'm on 4.7.1

[ForceFaction]

I tried the master and the following worked:

diff --git a/cmake/FindSIP.cmake b/cmake/FindSIP.cmake
index b93873f..4d3f703 100644
--- a/cmake/FindSIP.cmake
+++ b/cmake/FindSIP.cmake
@@ -56,7 +56,8 @@ execute_process(
    OUTPUT_STRIP_TRAILING_WHITESPACE
 )
 if(${_process_status} EQUAL 0)
-   string(STRIP ${_process_output} Python3_SITEARCH)
+   string(STRIP ${_process_output} _Python3_SITEARCH)
+   set(Python3_SITEARCH _Python3_SITEARCH CACHE PATH "Python modules install directory.")
 else()
    message(FATAL_ERROR "Failed to get Python3_SITEARCH. Error: ${_process_output}")
 endif()

This should do the trick, i guess

[ForceFaction]

@Ghostkeeper Is it possible this way? Or does it imply annoying side effects? If not it would be nice if this was added :)

[Ghostkeeper]

I think changing Python3_SITEARCH somewhere in the FindSIP script can have bad side effects: If another script uses Python3_SITEARCH it'll get a different directory based on whether this FindSIP script was executed before or after. So then maybe it's going to install some Python modules in one place, and other Python modules in another.

It also doesn't address the underlying problem that your Python3_SITEARCH was apparently incorrect or undesirable. This variable is the output of the FindPython3 script so I don't know if you're really supposed to change it. It would be better to change the inputs of that script, e.g. Python3_ROOT_DIR, if you have an alternative location where Python3 is installed.

Only we've since reverted to using FindPythonInterp since that worked better with our build servers which are using a rather old version of CMake (3.6). This script doesn't have any Python3_SITEARCH output variable nor does it have an input to tell it which Python interpreter to use.