error in find_package(), when building with custom message.

edit

Hello,

I have built ros2 from the latest stable source in Ubuntu 16.04. I was experimenting with colcon to build my own package as mentioned here and custom messages from this tutorial define custom interfaces/). My directory has the following structure:

--ros2_ws
      |--src
          |--pendulum_test
                      |--pendulum_controltwo
                            |--CMakeLists-.txt
                            |--package.xml
                            |--src
                                |--pendulum_demo.cpp
                      |--pendulumtwo_msgs
                            |--CMakeLists-.txt
                            |--package.xml
                            |--msg

my project is the same as pendulum_control and pendulum_msgs demo with appropriate name modifications in CMakeLists.txt and package.xml.

My build procedure is as follows:

1. In the pendulumtwo_msgs directory, I used

   colcon build

   It was successful

2. I sourced the pendulumtwo_msgs/install/local_setup.bash

3. In the pendulum_controltwo directory I used "colcon build" again

This gave me the following error:

-------------------------error starts here--------------------------

Starting >>> pendulumtwo_control
--- stderr: pendulumtwo_control                         
CMake Error at CMakeLists.txt:22 (find_package):
  By not providing "Findpendulumtwo_msgs.cmake" in CMAKE_MODULE_PATH this
  project has asked CMake to find a package configuration file provided by
  "pendulumtwo_msgs", but CMake did not find one.

  Could not find a package configuration file provided by "pendulumtwo_msgs"
  with any of the following names:

    pendulumtwo_msgsConfig.cmake
    pendulumtwo_msgs-config.cmake

  Add the installation prefix of "pendulumtwo_msgs" to CMAKE_PREFIX_PATH or
  set "pendulumtwo_msgs_DIR" to a directory containing one of the above
  files.  If "pendulumtwo_msgs" provides a separate development package or
  SDK, be sure it has been installed.


---
Failed   <<< pendulumtwo_control    [ Exited with code 1 ]

Summary: 0 packages finished [2.34s]
  1 package failed: pendulumtwo_control
  1 package had stderr output: pendulumtwo_control

---------------------error ends here-------------------------------------

The problem looked very similar to this thread. I looked in the build log and noticed that CMAKE_PREFIX_PATH was set to: /ros2_ws2/src/pendulum_test/pendulumtwo_msgs/install/pendulum_msgs and the cmake files mentioned in the error are present in the recently mentioned install directory. I'm not sure if CMAKE_FIND_ROOT_PATH is being overrided some how as mentioned in the referenced thread.

I hope my build procedure is correct and any advice on solving this error would be appreciated.

package.xml:

<?xml version="1.0"?>
<?xml-model href="http://download.ros.org/schema/package_format2.xsd" schematypens="http://www.w3.org/2001/XMLSchema"?>
<package format="2">
  <name>pendulum_controltwo</name>
  <version>0.5.1</version>
  <description>Demonstrates ROS 2's realtime capabilities with a simulated inverted pendulum.</description>

  <maintainer email="mikael@osrfoundation.org">Mikael Arguedas</maintainer>

  <license>Apache License 2.0</license>

  <author>Jackie Kay</author>

  <buildtool_depend>ament_cmake</buildtool_depend>

  <build_depend>rclcpp</build_depend>
  <build_depend>pendulumtwo_msgs</build_depend>
  <build_depend>rttest</build_depend>

  <exec_depend>rclcpp</exec_depend>
  <exec_depend>pendulumtwo_msgs</exec_depend>
  <exec_depend>rttest</exec_depend>

  <export>
    <build_type>ament_cmake</build_type>
  </export>
</package>

CMakeLists.txt:

cmake_minimum_required(VERSION 3.5)

project(pendulum_controltwo)

if(APPLE OR WIN32)
  message(STATUS "The pendulum_control demo is only supported on Linux. Package will not be built.")
  return()
endif()

find_package(ament_cmake REQUIRED)

# Default to C++14
if(NOT CMAKE_CXX_STANDARD)
  set(CMAKE_CXX_STANDARD 14)
endif()

if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
  add_compile_options(-Wall -Wextra -Wpedantic)
endif()

find_package(rclcpp REQUIRED)
find_package(pendulumtwo_msgs REQUIRED)
find_package(rttest)

include_directories(include)

if(NOT rttest_FOUND)
  message(STATUS "rttest not found. pendulum_control package will not be built.")
  return()
endif()

add_executable(pendulum_demo${target_suffix}
  src/pendulum_demo.cpp)
ament_target_dependencies(pendulum_demo${target_suffix}
  "pendulumtwo_msgs"
  "rclcpp${target_suffix}"
  "rttest ...