Trying to build with Ninja results nrfjprog.py in an AttributeError.

Question

I am able to build my project, but when I try to flash it to the board via ninja flash_<target> I can select the device in nrfjprog.py, I know, that I have to use "'0'" as input, so that the script doesn't result in an error, but then I get the following error: 
 nrf5_SDK_for_Mesh_v4.0.0_src/CMake/nrfjprog.py", line 93, in main
with multiprocessing.Pool(len(devices)) as p:
AttributeError: __exit__ 
 Is there a way to fix this?

Tilltheman · Answer

So I think I found the solution to this problem. I am using the SDK on an Ubuntu machine, as I said. On this machine I have two versions of python installed. Python2.7 and python3.6. cmake version is 3.10. When I try to build my project, cmake searches for the PythonInterpreter by calling 
 find_package(PythonInterp) 
 This for whatever reason does not return the interpreter for python3 but for python2.7. But the required one is Python3, because in Python3 the input-function always returns a String, instead of like in python2, where it returns an int if you enter 0. So in the CMakeLists.txt I changed the code to 
 # Needed tools for generating documentation and serial PyACI
if(CMAKE_VERSION VERSION_LESS 3.12)
 find_package(PythonInterp 3 REQUIRED)
else ()
 find_package(Python3)
endif()
find_package(Doxygen) 
 in order to use at least Python3 and from cmake version 3.12 on FindPythonInterp is deprecated. I did not test it with a cmake version higher than 3.12 yet, I hope it helps some people anyways.

Tilltheman · Answer

Hello Hung, 
 I just testet this on a machine with higher cmake package. We also have to actually set PYTHON_EXECUTABLE in the else-Part, because when searching for package Python3, cmake will set Python3_EXECUTABLE, where in the cmake-scripts it is checked for the existance of PYTHON_EXECUTABLE. So the code has to be the following: 
 # Needed tools for generating documentation and serial PyACI
if(CMAKE_VERSION VERSION_LESS 3.12)
 find_package(PythonInterp 3 REQUIRED)
else ()
 find_package(Python3)
 SET(PYTHON_EXECUTABLE "${Python3_EXECUTABLE}")
endif()