[Noetic] changes to make it work with Python3

[ahcorde]

Changes to make it work with Python3

Signed-off-by: ahcorde ahcorde@gmail.com

[ahcorde]

For some reason when the second test starts in gazebo_ros called ros_network/ros_network_disabled.test Gazebo dies immediately. The test fails with a timeout failure.

I tested each one of them individually, and it works. any thoughts?

[ahcorde]

Chnged enviroment variable GAZEBO_MASTER_URI to avoid the issue the collision of gazebo instances because of the binded ports

[mabelzhang]

A few minor comments. Should the Python files have python3 in the shebang or are they intended to still support python 2?

gazebo_ros tests worked for me. I didn't run the gazebo_plugins tests (that's problem on my end. I can't get its dependencies to compile yet...)

[ahcorde]

shebang lines look like : #! /usr/bin/env python. Ubuntu Focal only allows Python3 which I think it's fine with the python version installed in the system

[mabelzhang]

I think for Python3, usually the shebang lines would look like #!/usr/bin/env python3.

[sloretz]

A few minor comments. Should the Python files have python3 in the shebang or are they intended to still support python 2?

@mabelzhang @ahcorde IIUC PEP 394 recommends shebangs match the python version (python2 or python3) when they're installed. There's a CMake macro catkin_install_python() that writes the shebang to the specific python version used. The current recommendation is to use #!/usr/bin/env python and catkin_install_python() http://wiki.ros.org/UsingPython3/SourceCodeChanges#Changing_shebangs . Is that macro being used here?

[mabelzhang]

Thank you for the clarification and the link!
Looks like the current CMakeLists.txt for gazebo_plugins and gazebo_ros do not have catkin_install_python()
https://github.com/ros-simulation/gazebo_ros_pkgs/blob/noetic-devel/gazebo_plugins/CMakeLists.txt
https://github.com/ros-simulation/gazebo_ros_pkgs/blob/noetic-devel/gazebo_ros/CMakeLists.txt

[ahcorde]

the scripts in gazebo_ros are written in bash not in Python. Should I install them with catkin_install_python()?

[sloretz]

the scripts in gazebo_ros are written in bash not in Python. Should I install them with catkin_install_python()?

Definitely not. If they're bash scripts, what has the #!/usr/bin/env python shebang?

[ahcorde]

gazebo_ros has some, but right now it's fixed 6cabcc7

[sloretz]

LGTM! Tests pass on my machine using Gazebo 11 (currently using gazebo11 from packages.osrfoundation.org, but hope to use packages.ros.org when that becomes available).

[sloretz]

@chapulina @j-rivero I think this should go in before the other Noetic PRs since it has changes required for Noetic. Mind taking a look, and if it looks ok then merging it?

[chapulina]

Works for me. Let's just merge it like this, but beware that the *11 rosdep keys are not working yet, see ros-infrastructure/reprepro-updater#75 (comment).