Userfriendly error message for missing DEPENDENCIES in generate_messages

[mkjaergaard]

If the correct dependencies are not specified in generate_messages macro the genmsg will spit out a confusing python error. This should give a usefull error like:
"actionlib_msgs not found when generating for actionlib. Did you forget to specify actionlib_msgs in generate_messages() DEPENDENCIES" or something similar....

The current error message is:

--- Error parsing token: @{
import sys, genmsg, os
genmsg.base.log_verbose('GENMSG_VERBOSE' in os.environ)
# put this path at the beginning
sys.path.insert(0, genmsg_python_path)
import genmsg.deps

msg_deps = {}
for m in messages:
  msg_deps[m] = genmsg.deps.find_msg_dependencies(pkg_name, m, dep_search_paths)

srv_deps = {}
for s in services:
  srv_deps[s] = genmsg.deps.find_srv_dependencies(pkg_name, s, dep_search_paths)

}
    if __name__ == '__main__': main()
  File "/usr/bin/empy", line 3290, in main
    invoke(sys.argv[1:])
  File "/usr/bin/empy", line 3273, in invoke
    interpreter.wrap(interpreter.file, (file, name))
  File "/usr/bin/empy", line 2273, in wrap
    self.fail(e)
  File "/usr/bin/empy", line 2264, in wrap
    apply(callable, args)
  File "/usr/bin/empy", line 2337, in file
    self.safe(scanner, done, locals)
  File "/usr/bin/empy", line 2379, in safe
    self.parse(scanner, locals)
  File "/usr/bin/empy", line 2400, in parse
    token.run(self, locals)
  File "/usr/bin/empy", line 1410, in run
    interpreter.execute(self.code, locals)
  File "/usr/bin/empy", line 2580, in execute
    exec statements in self.globals
  File "<string>", line 10, in <module>
  File "/home/local/catkin_build2/build/lib/genmsg/deps.py", line 17, in find_msg_dependencies
    genmsg.msg_loader.load_depends(msg_context, spec, search_paths)
  File "/home/local/catkin_build2/build/lib/genmsg/msg_loader.py", line 343, in load_depends
    return load_msg_depends(msg_context, spec, msg_search_path)
  File "/home/local/catkin_build2/build/lib/genmsg/msg_loader.py", line 320, in load_msg_depends
    load_msg_depends(msg_context, depspec, search_path)
  File "/home/local/catkin_build2/build/lib/genmsg/msg_loader.py", line 312, in load_msg_depends
    depspec = load_msg_by_type(msg_context, resolved_type, search_path)
  File "/home/local/catkin_build2/build/lib/genmsg/msg_loader.py", line 118, in load_msg_by_type
    file_path = get_msg_file(package_name, base_type, search_path)
  File "/home/local/catkin_build2/build/lib/genmsg/msg_loader.py", line 78, in get_msg_file
    % (base_type, package, search_path))
genmsg.msg_loader.MsgNotFound: Cannot locate message [GoalID]: unknown package [actionlib_msgs] on search path [{'actionlib': '/home/local/catkin_build2/build/actionlib/actions_gen', 'std_msgs': '/home/local/catkin_build2/std_msgs/msg'}]
CMake Error at catkin/cmake/safe_execute_process.cmake:13 (message):
  Error executing process with arguments COMMAND
  /home/local/catkin_build2/build/env.sh /usr/bin/empy --raw-errors -F
  /home/local/catkin_build2/catkin/cmake/empy_util.py -F
  /home/local/catkin_build2/build/actionlib/cmake/actionlib-genmsg-context.py
  -F /home/local/catkin_build2/build/catkin/catkin-context.py -o
  /home/local/catkin_build2/build/actionlib/cmake/actionlib-genmsg.cmake
  /home/local/catkin_build2/genmsg/cmake/pkg-genmsg.cmake.em
Call Stack (most recent call first):
  catkin/cmake/em_expand.cmake:14 (safe_execute_process)
  build/cmake/genmsg/genmsg-extras.cmake:101 (em_expand)
  actionlib/CMakeLists.txt:28 (generate_messages)

[dawonn]

agreed, especially for someone new to catkin who is pretty sure he included all the proper depend strings and is very confused as to why it is 'missing'..... /le sigh...

[jbohren]

Three months after the groovy release I find myself adding the documentation to actually build a real package that generates ROS messages that depend on other messages...

[jbohren]

Not to mention the fact that "std_msgs" is mentioned in the following places if you want to use something in std_msgs in a message that you generate:

<build_depend>std_msgs</build_depend>
<run_depend>std_msgs</run_depend>

find_package(catkin REQUIRED COMPONENTS std_msgs)
#...
generate_messages(DEPENDENCIES std_msgs)
#...
catkin_package(CATKIN_DEPENDS std_msgs)

Yes I understand this is a catkin issue as much as it's a genmsg issue. @tkruse

[jbohren]

I am surprised that generate_messages() automatically creates install targets for the messages. It's uncharacteristically user-friendly in that regard.

[jbohren]

Thanks!