message and crate generation

[christianrauch]

I am trying to build https://github.com/esteve/ros2_rust/pull/3 but the examples fail because of the missing std_msgs crate. I manually cloned common_interfaces to the workspace and the std_msgs get successfully generated in install/std_msgs/share/std_msgs/rust/src.
I then added std_msgs = { path = '[...]/rust_ws/install/std_msgs/share/std_msgs/rust' } to the dependencies section in the rclrs_examples but cargo still cannot find the std_msgs crate.
I did not apply the patch rosidl_typesupport_ros2_rust.patch since the rust code was successfully generated.

How do I set the path to the crate such that cargo is able to build the examples?
Also, is it possible to reuse already installed message definitions (e.g. from package ros-crystal-std-msgs) instead of duplicating the messages in the workspace?

[christianrauch]

The path to the std_msgs crate was already set and the compilation failed because I set it twice.

I can compile the examples now by registering the generator: lelongg#1

But I still need to add std_msgs and builtin_interfaces manually to the workspace. It would be useful if the *.msg or *.idl could be reused.

[nnmm]

This should not be an issue anymore when following instructions in the README, and to the extent that it is still an issue, I think #11 covers it.