Include listing of rosdep sources in the pull request blurb

[tfoote]

We found an instance of someone who locally modified the rosdep sources locally to extend for wily and xenial, but the changes were never pushed back to the rosdep database. As such the debian package could build on the farm, but could not be installed from source due to missing rosdep rules. Also the devel jobs will fail due to the failure to resolve dependencies.

We don't want to prevent people from using custom rosdep rules in general, especially to support things like custom buildfarms etc. But having the rosdep sources that bloom used to resolve would be good for verification of pull requests. This won't automatically catch the fix, but we can at least catch it in review, and also find it later if we need to search. We found this one case since it's just added new dependencies in a predictable manner, but without that there is no way we could have known what happened under the hood.

[wjwwood]

This certainly could be added, but wouldn't it also make sense to check in the rosdistro? It has the package.xml's in the release cache and it knows what rosdep sources the build farm will use (presumably)? What determines which rosdep sources the build farm uses?

[tfoote]

We can only check if there's a source entry. And we do kind of have a check already that the devel jobs fail: http://build.ros.org:8080/job/Kdev__vision_opencv__ubuntu_xenial_amd64/ though that's not exhaustive.

We could extend @mikepurvis 's extended rosdistro cache possibly?

The biggest thing I'm hoping bloom will catch is to backtrace where the embedded dependencies in the control files came from.

[mikepurvis]

IMO, the rosdistro's index.yaml file should point to the rosdep path relative to itself, and bloom should resolve using those. Just parse the yaml manually from within bloom, and dump all of the create_default_installer_context madness— bypass the system rosdep entirely.

We're doing this to resolve deps for our bundle builds, and it's very nice.

[stonier]

Just to flesh out what caused the problem in more detail - we had a rosdep rules file installed in /etc/ros/rosdep/sources.list.d/25-yujin.list with contents:

yaml https://raw.githubusercontent.com/yujinrobot/rosdistro/master/rosdep/yujinrobot-build-indigo.yaml
yaml https://raw.githubusercontent.com/yujinrobot/rosdistro/master/rosdep/yujinrobot-system.yaml

However we didn't include the third argument to the first line to filter it exclusively for indigo, i.e. the following corrects the situation.

yaml https://raw.githubusercontent.com/yujinrobot/rosdistro/master/rosdep/yujinrobot-build-indigo.yaml indigo
yaml https://raw.githubusercontent.com/yujinrobot/rosdistro/master/rosdep/yujinrobot-system.yaml

Definitely having a way for bloom to introspect what it used would be useful for debugging.