Building with ros_comm in catkin_ws fails on test_rosmaster::String

[lucasw]

When I have ros_comm in my catkin_ws building with rosrust fails with:

...
  |       function or associated item `new` not found for this
  |       function or associated item not found in `test_rosmaster::String`
  |
  = help: items from traits can only be used if the trait is implemented and in scope
  = note: the following traits define an item `new`, perhaps you need to implement one of them:
          candidate #1: `error_chain::ChainedError`
          candidate #2: `gimli::read::lookup::PubStuffEntry`
          candidate #3: `aho_corasick::Transitions`
          candidate #4: `rand::distributions::uniform::UniformSampler`
          candidate #5: `error_chain::ChainedError`

test_rosmaster::String is built by ros_comm by default in devel, it doesn't get installed.

This docker command replicates it:

docker run --rm -it ros:noetic-robot bash -c "\
apt update && \
apt install -y curl git && \
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y && \
source /root/.cargo/env && \
source /opt/ros/noetic/setup.bash && \
mkdir catkin_ws/src -p && \
cd catkin_ws/src && \
git clone https://github.com/ros/ros_comm.git && \
cd .. && \
catkin build && \
source devel/setup.bash && \
cd .. && \
git clone https://github.com/adnanademovic/rosrust.git && \
cd rosrust && \
cargo build"

I've tried a few variations on not building the test_rosmaster messages at all but it's odd because the generated rosrust::rosmsg_include!(... ends up including them anyway and fails the same way. It even finds messages completely outside of the sourced workspace in a separate development workspace (but within my $HOME), rosmsg list won't show the messages as expected but rosrust_msg still finds them. Using a catkin install process didn't help. I can document that better in a separate issue with docker commands to reproduce.

This looks similar to #134

I've got additional less organized notes here lucasw/rust_test#1

[jobafr]

I can confirm this.