Hello @dirk-thomas, could you please grant me (or someone else) the necessary privileges to release this package to PyPI?

(reporting this here as I installed colcon-common-extensions)

ubuntu:xenial Docker container. Followed installation instructions with a python3 venv.

This installed most of the things I'd expect, but upon first time invoking colcon --help, I got:

ERROR:colcon.colcon_core.entry_point:Exception loading extension 'colcon_core.python_testing.pytest': No module named '_pytest'
Traceback (most recent call last):
  File "/catkin_ws/colcon_venv/lib/python3.5/site-packages/colcon_core/entry_point.py", line 86, in load_entry_points
    extension_type = load_entry_point(entry_point)
  File "/catkin_ws/colcon_venv/lib/python3.5/site-packages/colcon_core/entry_point.py", line 128, in load_entry_point
    return entry_point.load()
  File "/catkin_ws/colcon_venv/lib/python3.5/site-packages/pkg_resources/__init__.py", line 2229, in load
    return self.resolve()
  File "/catkin_ws/colcon_venv/lib/python3.5/site-packages/pkg_resources/__init__.py", line 2235, in resolve
    module = __import__(self.module_name, fromlist=['__name__'], level=0)
  File "/catkin_ws/colcon_venv/lib/python3.5/site-packages/colcon_core/task/python/test/pytest.py", line 7, in <module>
    from _pytest.main import EXIT_NOTESTSCOLLECTED
ImportError: No module named '_pytest'

usage: colcon [-h] [--log-level LOG_LEVEL]
              {build,extension-points,extensions,info,list,metadata,test,test-result}
              ...
...

After manually installing pytest in the virtualenv, this error disappeared.

Seems to me like colcon-clean should be part of the common extension as it is a "basic functionality" (as was catkin clean in ROS 1)

Relates to #18

I notice python3-colcon-mixin isn't installed with ros-dev-tools, and isn't part of python3-colcon-common-extensions.

Thoughts on adding it? The mixin documentation is already included in the "reference" section of the colcon documentation, so it would seem natural to me to make it one of the default plugins.

https://colcon.readthedocs.io/en/released/reference/verb/mixin.html

It would be great if tagged releases of colcon-common-extensions (pypi and/or deb) had pinned versions of colcon components, so it would be possible to install a consistent 'older' version of colcon.

For simplicity of CI config reasons I'd like to use colcon in the same way on 18.04 as I am on 20.04. I've been trying to use the pip based source install but it seems that it is missing some features (specifically the mixin verb and argument to build). I'm not sure what I'm doing wrong.

Note that I first tried using colcon via the debian packages and it is missing the mixin feature there too.

I discovered there is a package python3-colcon-mixin that I needed. However, now after trying to update mixin I don't have any available (colcon mixin list shows nothing).

$ colcon mixin show build
Passed verb name 'build' has no mixins

In case anyone else finds this in the future this is what I needed to do:

sudo apt install python3-colcon-mixin
colcon mixin add default https://raw.githubusercontent.com/colcon/colcon-mixin-repository/master/index.yaml
colcon mixin update default

I created a colcon extension for meson packages: https://github.com/christianrauch/colcon-meson and would like to have this moved inside the @colcon organisation for continued maintenance and releases to the Python Package Index.

This currently implements the bare minimum to identify, build and install meson packages.

To test it, build the libcamera and simple-cam packages.

# download colcon-meson and meson examples
mkdir -p ~/cam_ws/src
cd ~/cam_ws/src
git clone https://github.com/christianrauch/colcon-meson.git
git clone https://git.libcamera.org/libcamera/libcamera.git
git clone https://git.libcamera.org/libcamera/simple-cam.git
cd ~/cam_ws

# build colcon-meson
colcon build

# list packages
source install/setup.bash
colcon list
# should list:
#   colcon-meson	colcon-meson	(python)
#   libcamera	libcamera	(meson)
#   simple-cam	simple-cam	(meson)

# build 'libcamera' and 'simple-cam'
colcon build

# source workspace again and run the camera example
source install/setup.bash
qcam

@nuclearsandwich FYI. We had a quick chat about adding meson support a while ago. This should get this started.