Getting rosbag2-bag-v2-plugins to build

[acowley]

The rosbag2-bag-v2-plugins package did not build out of the box for me with the following error,

> -- Checking for module 'roscpp'
> --   No package 'roscpp' found
> CMake Error at CMakeLists.txt:28 (message):
>   Failed to find ROS 1 roscpp, cannot build.

I was eventually able to get through the configure phase with these changes,

rosbag2-bag = ros.rosbag2-bag-v2-plugins.overrideAttrs (old: {
            buildInputs = old.buildInputs or [] ++ [ros1.roscpp ros1.cpp-common ros1.rosbag-storage];
            nativeBuildInputs = old.nativeBuildInputs or [] ++ [ros.pluginlib ros.std-msgs ros.rosgraph-msgs];
          });

Where I am working with flakes, and have,

ros = ros-flake.packages.${system}.foxy;
ros1 = ros-flake.packages.${system}.noetic;

The configure error I showed was due to pkg-config failing to find the things I added to buildInputs. Later during the configure phase, various msg definitions are wanted for code generation, so I added those dependencies.

I also had to hand edit the CMakeLists.txt file to mention ros1_rosbag_storage_vendor rather than ros1_rosbag_storage. That name is used to construct file names for cmake to look for which it fails to find as the actual files in the nix store have the _vendor part.

The next problem is that the build phase fails with,

Traceback (most recent call last):
  File "/home/acowley/Projects/ros/bag/rosbag2_bag_v2-release-release-foxy-rosbag2_bag_v2_plugins-0.0.10-1/src/generate_converter_cpp.py", line 19, in <module>
    from ros1_bridge import generate_messages
ModuleNotFoundError: No module named 'ros1_bridge'

I am a bit stuck here as the Python parts of ros1_bridge seem to be lost at some point.

So my questions are:

1. Have I gone too far into the weeds here? Am I just missing a simpler fix for the original failure of this package not building?
2. If I'm on a more or less good path to fixing this, can you suggest a maneuver to get the ros1-bridge python components included in its output?

Thank you!

[lopsided98]

The core of the problem is that these packages depend on ROS 1 packages, which can't be specified in package.xml for a ROS 2 package. Also, it so happens that if ros1-rosbag-storage-vendor doesn't find roscpp, it just installs an empty package rather than failing. This is why you had to edit CMakeLists.txt.

I fixed those issues in #114, but I'm now running into this error:

CMake Error at CMakeLists.txt:74 (add_library):
  Target "rosbag2_bag_v2_plugins" links to target
  "std_msgs::std_msgs__rosidl_typesupport_cpp" but the target was not found.
  Perhaps a find_package() call is missing for an IMPORTED target, or an
  ALIAS target is missing?

I'm not sure what's wrong here, but I'm thinking that this code is supposed to call find_package(std_msgs), but for some reason ament_index_get_resources() isn't finding std_msgs.