catkin_tools_prebuild:cmake step fails if the Travis CI language is "cpp"

[pjreed]

I have a few repositories that I want to build with both clang and gcc. In order for the compiler: value in the .travis.yml file to work, the language: needs to be set to cpp rather than generic; otherwise it will only compile using gcc. However, If I make that change, the build fails almost immediately. When cmake is running for the first package, it prints out this error:

[catkin_tools_prebuild:cmake] -- Found gtest sources under '/usr/src/gtest': gtests will be built
[catkin_tools_prebuild:cmake] -- Using Python nosetests: /usr/bin/nosetests-2.7
[catkin_tools_prebuild:cmake] ImportError: "from catkin_pkg.package import parse_package" failed: No module named catkin_pkg.package
[catkin_tools_prebuild:cmake] Make sure that you have installed "catkin_pkg", it is up to date and on the PYTHONPATH.
[catkin_tools_prebuild:cmake] CMake Error at /opt/ros/indigo/share/catkin/cmake/safe_execute_process.cmake:11 (message):
[catkin_tools_prebuild:cmake]   execute_process(/opt/python/2.7.10/bin/python
[catkin_tools_prebuild:cmake]   "/opt/ros/indigo/share/catkin/cmake/parse_package_xml.py"
[catkin_tools_prebuild:cmake]   "/opt/ros/indigo/share/catkin/cmake/../package.xml"
[catkin_tools_prebuild:cmake]   "/home/travis/ros/ws_marti_common/build/catkin_tools_prebuild/catkin/catkin_generated/version/package.cmake")
[catkin_tools_prebuild:cmake]   returned error code 1
[catkin_tools_prebuild:cmake] Call Stack (most recent call first):
[catkin_tools_prebuild:cmake]   /opt/ros/indigo/share/catkin/cmake/catkin_package_xml.cmake:63 (safe_execute_process)
[catkin_tools_prebuild:cmake]   /opt/ros/indigo/share/catkin/cmake/all.cmake:151 (_catkin_package_xml)
[catkin_tools_prebuild:cmake]   /opt/ros/indigo/share/catkin/cmake/catkinConfig.cmake:20 (include)
[catkin_tools_prebuild:cmake]   CMakeLists.txt:4 (find_package)

If I set the language back to generic, the error goes away. In the build log, it does look like the python-catkin-pkg package was installed, so I'm not sure why cmake can't find it. Here's a complete example of a build log: https://travis-ci.org/pjreed/marti_common/jobs/125634383

[130s]

Thanks for the report!
Glad that you managed to work around the issue (I believe in swri-robotics/marti_common#318). Although my workload this week is limited, I feel like implementing something permanent to industrial_ci for this issue (code, or doc).

Travis CI does special thing with language: cpp for the convenience for Autotools and make, but I'm not sure how that effects cmake-based catkin.

https://docs.travis-ci.com/user/languages/cpp

Default Test Script #

Because C++ projects on travis-ci.org assume Autotools and Make by default, naturally, the default command Travis CI will use to run your project test suite is

./configure && make && make test

Projects that find this sufficient can use a very minimalistic .travis.yml file:
language: cpp

[mathias-luedtke]

If I remember it correctly the "language: cpp" pulls in a wrong/incompatible python version.

otherwise it will only compile using gcc

Can't you just install another compiler and set the CC/CXX environment variables?
This way I am using clang on my machines.

[pjreed]

I can, although being able to use the compiler: setting is nice because Travis CI will generate a build matrix from all of the permutations of that and all of the other environment variables I've set in the matrix: section. I can work around it, it just means having to manually add gcc and clang variations of all of the existing matrix lines.

[mathias-luedtke]

This should be resolved because all command are run in docker now.
However, the build matrix feature cannot be used.