roslz4 linking against the wrong python version

[spaghetti-]

Something with the CMakeFiles.txt of roslz4 makes it disregard python overrides. On my most recent compilation os MacOS Sierra -

./src/catkin/bin/catkin_make_isolated --install --install-space /opt/ros/kinetic -DSETUPTOOLS_DEB_LAYOUT=OFF -DCMAKE_BUILD_TYPE=RelWithDebInfo  -DCMAKE_PYTHON_EXECTUABLE=`which python` -DCMAKE_PYTHON_LIBRARY=/usr/local/Frameworks/Python.framework/Versions/2.7/lib/libpython2.7.dylib --pkg roslz4

❯ python -c "import rosbag"
Fatal Python error: PyThreadState_Get: no current thread
[1]    89264 abort      python -c "import rosbag"

Because

❯ otool -L _roslz4.so
_roslz4.so:
        _roslz4.so (compatibility version 0.0.0, current version 0.0.0)
        libroslz4.dylib (compatibility version 0.0.0, current version 0.0.0)
        /System/Library/Frameworks/Python.framework/Versions/2.7/Python (compatibility version 2.7.0, current version 2.7.10)
        /usr/local/opt/lz4/lib/liblz4.1.dylib (compatibility version 1.0.0, current version 1.7.1)
        /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1238.0.0)

Fixed by

install_name_tool -change /System/Library/Frameworks/Python.framework/Versions/2.7/Python /usr/local/Frameworks/Python.framework/Versions/2.7/Python _roslz4.so

It shouldn't happen because I specified my python libs, so it could be a bug.

[dirk-thomas]

The package is using the Python include dir as well as Python library detected in CMake (

ros_comm/utilities/roslz4/CMakeLists.txt

Line 39 in 753ff95

find_package(PythonLibs "${PYTHON_VERSION_MAJOR}.${PYTHON_VERSION_MINOR}" REQUIRED)

). I don't know if / how the CMake module takes your arguments into considerations. The code of the Python CMake module will show what is happening and if there is a way to pass a specific library dir.

[mikepurvis]

In ros-install-osx, we set PYTHON_LIBRARY and PYTHON_INCLUDE_DIR; this has seemed to work consistently, at least when targeting brewed python:

https://github.com/mikepurvis/ros-install-osx/blob/fb9febdcfa9b965b0b6f347f4963d9277b1d1b26/install#L159-L160

[mikepurvis]

Note that as of Trusty, there's an upstream lz4 package; as of Xenial, there's an upstream python-lz4 bindings package:

http://packages.ubuntu.com/source/trusty/lz4
http://packages.ubuntu.com/source/xenial/python-lz4

Potentially for Lunar+, the roslz4 package could be hollowed out and made to delegate to these system implementations.

[oliverlee]

In ros-install-osx, we set PYTHON_LIBRARY and PYTHON_INCLUDE_DIR; this has seemed to work consistently, at least when targeting brewed python:

This still links to the wrong Python (at least for me) since roslz4 uses (deprecated) PYTHON_INCLUDE_PATH instead of PYTHON_INCLUDE_DIR.

[alper111]

This is still an issue on MacOS Catalina, and the solution @spaghetti- mentioned works for me.