Migrating from Fuerte catkin

Catkin still changes a lot, so a migration from catkin in fuerte to catkin in groovy is necessary. Changes to catkin in Groovy are not designed to be backwards compatible to catkin in Fuerte.

The main difference to know is that in fuerte, the atomic unit of build was a stack declared in a stack.xml file, whereas in groovy, stacks do no exist anymore, and the atomic unit is a package declared in a package.xml file.

If in fuerte you had a stack with several subprojects acting as packages, this should be migrated to one metapackage and several packages for groovy. If instead you had a stack with sources, this can become a single catkin package.

Metapackages are not required for packages, they may just be helpful to define a relationship between packages, and for installing your packages it might be easier to just give the name of a metapackage than to list all your packages.

To update an already catkinized ROS stack from the Fuerte-version of catkin to Groovy the following steps are necessary:

Make a metapackage for the stack

The version of Catkin for ROS groovy does not support the idea of a “stack” of packages which get wrapped up together into a Debian (or similar) installable package. Instead, catkin packages now get built into separate installable Debian (or similar) packages. To maintain compatibility with software which has a dependency on the stack name, you need to make a new catkin package which is a “metapackage”. This package has the same name as the stack and contains no source code, only a list of dependencies containing all the packages which used to be in the stack.

For example, say our old stack was named “stick” and it had 2 packages: “pickage” and “peckage”. The directories would look like this:

/stick/stack.xml
/stick/CMakeLists.xml
/stick/pickage/... (pickage files)
/stick/peckage/... (peckage files)

The new version adds a new “stick” metapackage subdirectory under /stick, along with a package.xml and CMakeLists.txt file:

/stick/stick/package.xml
/stick/stick/CMakeLists.xml
/stick/pickage/... (pickage files)
/stick/peckage/... (peckage files)

The contents of the /stick/stick/package.xml must look like this:

<package>
  <name>stick</name>
  <version>0.1.1</version>
  <description>Metapackage relevant to sticks.</description>
  <maintainer email="coder@example.com">Lucy Coder</maintainer>
  <license>BSD</license>

  <url type="website">http://www.example.com/stick</url>

  <buildtool_depend>catkin</buildtool_depend>

  <!-- a former stack run depends only on all its child packages -->
  <run_depend>pickage</run_depend>
  <run_depend>peckage</run_depend>

  <export>
    <metapackage/>
  </export>
</package>

The contents of the /stick/stick/CMakeLists.txt looks like this:

cmake_minimum_required(VERSION 2.8.3)
project(stick)
find_package(catkin REQUIRED)
catkin_metapackage()

Note that the package.xml for stick has a buildtool depend on catkin. This is required because the CMakeLists.txt for a metapackage contains a catkin macro (catkin_metapackage), therefore catkin is required at build time. This is the only non-run_depend allowed in the package.xml of a metapackage.

The rest of these instructions refer to changes within regular (not meta-) catkin packages.

Migrate packages

In fuerte, catkin had no strong notion of packages, only stacks, and package manifests were at most kept for backwards compatibility with rosbuild. In groovy, it was decided to instead drop the notion of stacks (for metapackages), and make packages the atomic unit of build.

1. Rename manifest.xml to package.xml, or create new package.xml.
2. Adapt the contents of package.xml

• add a name tag
• add a maintainer tag

3. Create/Update CMakeLists.txt` files

• Instead of find_package(ROS ...) use find_package(catkin ...).

Make sure to update the corresponding variables like ROS_INLCUDE_DIRS to catkin_INCLUDE_DIRS.

Do not search a component called catkin.

• catkin_package(...) should be called near the beginning of the CMake, directly after find_package-ing catkin and other dependencies. Unlike the old catkin_project() macro, catkin_package() doesn’t need the name of the package it is part of.

• Switch to renamed catkin functions:

  • add_gtest => catkin_add_gtest

    Do not use path-like string for the target name. The first argument must be a valid CMake target name.

  • add_nosetests => catkin_add_nosetests

• Update install() invocations to use the new FHS compliant destinations (see Variables). Always specify the necessary destinations explicitly.

  Specify DESTINATION, ARCHIVE DESTINATION, LIBRARY DESTINATION and RUNTIME DESTINATION as required.

• Remove manually install() invocations for stack.xml and manifest.xml files (this is handled by catkin automatically).

• After creating a GTest target using catkin_add_gtest(target ...) you should test for the existence of the target before trying to use it (i.e. by calling target_link_libraries(target ..,)):

  % if(TARGET target)
  %   target_link_libraries(target ...)
  % endif()

  This handles the case gracefully when GTest is not available.

CMake extra files

CMake extra files must now work in devel space as well as in installspace. The templates can determine the different invocation cases using the variables @DEVELSPACE@ and @INSTALLSPACE@.

Custom find_package() config files

The find_package() config have been renamed from <projectname>-config.cmake.in to <ProjectName>Config.cmake.in. Note that the project name is no longer converted to lower case but used as-is.

Custom environment hooks

The names of the templates for the environment hooks for devel space and installspace have been unified. There is only one template for both. The templates can determine the different invocation cases using the variables @DEVELSPACE@ and @INSTALLSPACE@.