try/except for site.getsitepackages()

[guruofquality]

In the never ending python install path whack-a-mole, site.getsitepackages() sometimes does not exist

• resolves Installing in virtualenv not trivial #239

• @gasparka are you able to test this change on your setup?

[gasparka]

Error is fixed, but install prefix is wrong (/usr/local). It should be set to $VIRTUAL_ENV (/home/gaspar/git/rantelon/detector/venv) if exist.

Cmake log:

(venv) gaspar@RA-108 ~/git/rantelon/detector/environment/SoapySDR/build (master)> cmake ..
-- The C compiler identification is GNU 9.1.0
-- The CXX compiler identification is GNU 9.1.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Build type not specified: defaulting to release.
-- Found Doxygen: /usr/bin/doxygen (found version "1.8.16") found components:  doxygen dot 
-- 
-- #############################################
-- ## Begin configuration for Python support...
-- #############################################
-- Enabling optional Python bindings if possible...
-- Found SWIG: /usr/bin/swig (found version "4.0.1") 
-- SWIG_FOUND: TRUE - 4.0.1
-- Found PythonInterp: /home/gaspar/git/rantelon/detector/venv/bin/python (found version "3.7.4") 
-- PYTHONINTERP_FOUND: TRUE - 3.7.4
-- PYTHON_EXECUTABLE: /home/gaspar/git/rantelon/detector/venv/bin/python
-- PYTHON_INSTALL_DIR: ${prefix}/lib/python3.7/site-packages
-- PYTHONLIBS_FOUND: TRUE - 3.7.4
-- PYTHON_INCLUDE_DIRS: /home/gaspar/git/rantelon/detector/venv/include/python3.7m;/home/gaspar/git/rantelon/detector/venv/include/python3.7m
-- PYTHON_LIBRARIES: -lpython3.7m -lcrypt -lpthread -ldl -lutil -lm -Xlinker -export-dynamic
-- Performing Test SIZE_T_IS_UNSIGNED_INT
-- Performing Test SIZE_T_IS_UNSIGNED_INT - Failed
-- CMAKE_SWIG_FLAGS=-c++;-threads;-I/home/gaspar/git/rantelon/detector/environment/SoapySDR/include
CMake Warning (dev) at /usr/share/cmake-3.15/Modules/UseSWIG.cmake:607 (message):
  Policy CMP0078 is not set: UseSWIG generates standard target names.  Run
  "cmake --help-policy CMP0078" for policy details.  Use the cmake_policy
  command to set the policy and suppress this warning.

Call Stack (most recent call first):
  python/CMakeLists.txt:155 (SWIG_ADD_LIBRARY)
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) at /usr/share/cmake-3.15/Modules/UseSWIG.cmake:460 (message):
  Policy CMP0086 is not set: UseSWIG honors SWIG_MODULE_NAME via -module
  flag.  Run "cmake --help-policy CMP0086" for policy details.  Use the
  cmake_policy command to set the policy and suppress this warning.

Call Stack (most recent call first):
  /usr/share/cmake-3.15/Modules/UseSWIG.cmake:702 (SWIG_ADD_SOURCE_TO_MODULE)
  python/CMakeLists.txt:155 (SWIG_ADD_LIBRARY)
This warning is for project developers.  Use -Wno-dev to suppress it.

-- 
-- #############################################
-- ## Begin configuration for Python3 support...
-- #############################################
-- Enabling optional Python3 bindings if possible...
-- 
-- ######################################################
-- ## SoapySDR enabled features
-- ######################################################
-- 
 * Library, runtime library v0.8.0-gcafa4ba5
 * Apps, command line applications
 * Tests, library unit tests
 * Docs, doxygen documentation
 * Python, python bindings v3.7.4

-- ######################################################
-- ## SoapySDR disabled features
-- ######################################################
-- 

-- SoapySDR version: v0.8.0-gcafa4ba5
-- ABI/so version: v0.8
-- Install prefix: /usr/local
-- Configuring done
-- Generating done
-- Build files have been written to: /home/gaspar/git/rantelon/detector/environment/SoapySDR/build

[guruofquality]

Error is fixed,

Thanks

but install prefix is wrong (/usr/local). It should be set to $VIRTUAL_ENV (/home/gaspar/git/rantelon/detector/venv) if exist.

You are going to want to pass this to cmake: -DCMAKE_INSTALL_PREFIX=$VIRTUAL_ENV

[gasparka]

IMO #239 is not yet solved.

My argument is that -DCMAKE_INSTALL_PREFIX=$VIRTUAL_ENV should be set automatically because current situation results in broken install (using "naively" cmake .. in virtualenv). That is, install succeeds BUT you cant import SoapySDR - that is confusing to people who have little experience with cmake.

Is there any downside of setting it automatically (i mean only if $VIRTUAL_ENV is set, and of course it can be overwritten with -DCMAKE_INSTALL_PREFIX)?

[guruofquality]

Double checking: Should the libsoapysdr.so, support modules, and includes go into /usr/local, and the python modules should go into $VIRTUAL_ENV. Or all of the install, every lib and include should also be in the same $VIRTUAL_ENV prefix?

[gasparka]

My vision is that everything goes into $VIRTUAL_ENV, main system will stay untouched.

[guruofquality]

There could be upwards of 100 projects in this ecosystem from drivers to applications that would need to understand a new default for the install prefix (both cmake and autotools stuff --prefix). Typically the build projects try to stay generic but support configuration variables. And then depending upon the system, these variables are scripted in a way to match the target system. debian has a rules file, homebrew has recipes and standard cmake args, im sure setup.py could be scripted to do something too.

[gasparka]

My idea was that $VIRTUAL_ENV is used only if set - this happens when user has activated the virtual environment. Builds out of virtual environment will stay the same.

However, i understand that this use case is not that common, lets see if there are more people interested.

Thanks for help!