I would like to know if rosdep init and rosdep update that we perform during ROS installation make any changes outside the ROS environment? like does it update or modify the debian packages or any other non-ROS components? Thank you.
Originally posted by sam26 on ROS Answers with karma: 231 on 2017-02-21
Post score: 2
Well, rosdep init puts a file in /etc/ros/rosdep/, if this is "outside of the ROS environment" for you.
rosdep update fetches the new rosdep definition files and stores them somewhere too.
Other than that, rosdep does nothing as long as you don't do a rosdep install <PKG>. This will then install the required dependencies that are specified in the package. This can be other released ROS packages or third party packages as debian pkgs or from any other package manager, e.g. pip.
Originally posted by mgruhler with karma: 12390 on 2017-02-21
This answer was ACCEPTED on the original site
Post score: 3
Comment by sam26 on 2017-02-21:
Thank you. But does rosdep update updates the package list of other package managers too or does it just update the available ROS package list?
Comment by gvdhoorn on 2017-02-21:
@sam26: it does not install any package or change anything besides the files that @mig already mentioned (ie: /etc/ros/rosdep) and a cache in your $HOME.
Comment by mgruhler on 2017-02-21:
Just the rosdep definitions. Those are "remappings" pointing to specific, distro dependent version. They are defined, e.g. here. Thus, the rosdep key ace points to ace for arch and libace-dev for debian...
Comment by sam26 on 2017-02-21:
Thank you!
Comment by sam26 on 2017-02-22:
@mig @gvdhoorn But when I look at the sources that rosdep sources.listcontains, it points to packages that are present in universe and multiverse as well ( non-ROS packages ). So rosdep update would update these non-ROS packages right (just like apt-get update) ?
Comment by gvdhoorn on 2017-02-22:
rosdep only uses a 20-default.list in /etc/ros/rosdep/sources.list.d, and that does not contain any mention of universe or multiverse.
But in any case: rosdep itself will never install or upgrade anything, that is the pkg mgrs job, only after you accept what it wants to do.
