use ament export targets

.github/workflows/colcon_ament.yml

@@ -0,0 +1,58 @@
+name: colcon ament Ubuntu
+
+on: [push, pull_request]
+
+env:
+  # Customize the CMake build type here (Release, Debug, RelWithDebInfo, etc.)
+  BUILD_TYPE: Release
+
+jobs:
+  build:
+    container: osrf/ros:${{matrix.ros_distro}}-desktop
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-22.04]
+        ros_distro: [humble, rolling]
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Install binary dependencies with rosdep
+      id: rosdep
+      run: |
+        apt update
+        rosdep update
+        source /opt/ros/${{matrix.ros_distro}}/setup.bash
+        rosdep install --from-paths src --ignore-src -y
+      shell: bash
+
+    - name: Build with colcon
+      id: colcon-build
+      run: |
+        source /opt/ros/${{matrix.ros_distro}}/setup.bash
+        colcon build
+      shell: bash
+
+    - name: Test with colcon
+      id: colcon-test
+      run: |
+        source /opt/ros/${{matrix.ros_distro}}/setup.bash
+        colcon test
+        colcon test-result --all --verbose
+      shell: bash
+
+    - name: Test consuming with ament_target_dependencies
+      run: |
+        source /opt/ros/${{matrix.ros_distro}}/setup.bash
+        # This sets the variable AMENT_PREFIX_PATH
+        source install/setup.bash
+        cd tests/export/ament_target_deps
+        colcon build
+
+    - name: Test consuming with target_link_libraries
+      run: |
+        source /opt/ros/${{matrix.ros_distro}}/setup.bash
+        # This sets the variable AMENT_PREFIX_PATH
+        source install/setup.bash
+        cd tests/export/target_link_libs
+        colcon build

CMakeLists.txt

@@ -50,6 +50,9 @@ endif()
 
 find_package(ament_cmake QUIET)
 
+# This is a private variable to control the exported namespace name for installation
+# macros that support namespace targets.
+set(_BTCPP_EXPORTED_NAMESPACE BT::)
 if ( ament_cmake_FOUND )
 
     add_definitions( -DUSING_ROS2 )

README.md

@@ -60,7 +60,7 @@ If you are looking for a more fancy graphical user interface (and I know you do)
 
 **BT.CPP** requires a compile that supports c++17.
 
-Three build systems are supported:
+Four build systems are supported:
 
 - **catkin**, if you use ROS
 - **colcon (ament)**, if you use ROS2

cmake/ament_build.cmake

@@ -18,8 +18,6 @@ set( BTCPP_EXTRA_LIBRARIES
     $<BUILD_INTERFACE:${SQLite3_LIBRARIES}>
 )
 
-ament_export_dependencies(ament_index_cpp)
-
 set( BTCPP_LIB_DESTINATION     lib )
 set( BTCPP_INCLUDE_DESTINATION include )
 set( BTCPP_BIN_DESTINATION     bin )
@@ -31,7 +29,11 @@ mark_as_advanced(
     BTCPP_BIN_DESTINATION )
 
 macro(export_btcpp_package)
-    ament_export_include_directories(include)
-    ament_export_libraries(${BTCPP_LIBRARY})
+    ament_export_targets(
+        ${PROJECT_NAME}Targets
+        NAMESPACE "{_BTCPP_EXPORTED_NAMESPACE}"
+        HAS_LIBRARY_TARGET
+    )
+    ament_export_dependencies(ament_index_cpp)
     ament_package()
 endmacro()

cmake/conan_build.cmake

@@ -29,7 +29,7 @@ macro(export_btcpp_package)
     install(EXPORT ${PROJECT_NAME}Targets
         FILE "${PROJECT_NAME}Targets.cmake"
         DESTINATION "${BTCPP_LIB_DESTINATION}/cmake/${PROJECT_NAME}"
-        NAMESPACE BT::
+        NAMESPACE "{_BTCPP_EXPORTED_NAMESPACE}"
         )
     export(PACKAGE ${PROJECT_NAME})
 

tests/export/README.md

@@ -0,0 +1,5 @@
+# Export tests
+
+The purpose of the tests below is to ensure that BTCPP exports itself correctly for use with find_package.
+
+Without testing this, it is easy to accidentally break consumer applications when working on CMake installation code.

tests/export/ament_target_deps/CMakeLists.txt

@@ -0,0 +1,15 @@
+cmake_minimum_required(VERSION 3.22.1) # version on Ubuntu Jammy
+project(btcpp_ament_tgt_dep LANGUAGES CXX)
+
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+find_package(ament_cmake 1 CONFIG REQUIRED)
+find_package(behaviortree_cpp 4 REQUIRED)
+
+add_executable(btcpp_sample main.cpp)
+
+# This function doesn't yet support PRIVATE as an argument.
+# See https://github.com/ament/ament_cmake/issues/158#issuecomment-475384147
+# Instead, test preserving legacy usage with no linkage specifier.
+ament_target_dependencies(btcpp_sample behaviortree_cpp)

tests/export/ament_target_deps/main.cpp

@@ -0,0 +1,78 @@
+// Copy of https://github.com/BehaviorTree/btcpp_sample/blob/main/main.cpp
+
+#include "behaviortree_cpp/bt_factory.h"
+
+using namespace BT;
+
+// clang-format off
+static const char* xml_text = R"(
+
+ <root BTCPP_format="4" >
+
+     <BehaviorTree ID="MainTree">
+        <Sequence name="root">
+            <AlwaysSuccess/>
+            <SaySomething   message="this works too" />
+            <ThinkWhatToSay text="{the_answer}"/>
+            <SaySomething   message="{the_answer}" />
+        </Sequence>
+     </BehaviorTree>
+
+ </root>
+ )";
+// clang-format on
+
+class SaySomething : public BT::SyncActionNode
+{
+  public:
+  SaySomething(const std::string& name, const BT::NodeConfig& config) :
+        BT::SyncActionNode(name, config)
+  {}
+
+  BT::NodeStatus tick() override
+  {
+    std::string msg;
+    getInput("message", msg);
+    std::cout << msg << std::endl;
+    return BT::NodeStatus::SUCCESS;
+  }
+
+  static BT::PortsList providedPorts()
+  {
+    return {BT::InputPort<std::string>("message")};
+  }
+};
+
+class ThinkWhatToSay : public BT::SyncActionNode
+{
+  public:
+  ThinkWhatToSay(const std::string& name, const BT::NodeConfig& config) :
+        BT::SyncActionNode(name, config)
+  {}
+
+  BT::NodeStatus tick() override
+  {
+    setOutput("text", "The answer is 42");
+    return BT::NodeStatus::SUCCESS;
+  }
+
+  static BT::PortsList providedPorts()
+  {
+    return {BT::OutputPort<std::string>("text")};
+  }
+};
+
+int main()
+{
+
+  BehaviorTreeFactory factory;
+
+  factory.registerNodeType<SaySomething>("SaySomething");
+  factory.registerNodeType<ThinkWhatToSay>("ThinkWhatToSay");
+
+  auto tree = factory.createTreeFromText(xml_text);
+
+  tree.tickWhileRunning();
+
+  return 0;
+}

tests/export/target_link_libs/CMakeLists.txt

@@ -0,0 +1,16 @@
+cmake_minimum_required(VERSION 3.22.1) # version on Ubuntu Jammy
+project(btcpp_tgt_link_libs LANGUAGES CXX)
+
+
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+find_package(ament_cmake 1 CONFIG REQUIRED)
+set(CMAKE_FIND_DEBUG_MODE TRUE)
+find_package(behaviortree_cpp 4 CONFIG REQUIRED)
+set(CMAKE_FIND_DEBUG_MODE FALSE)
+
+add_executable(btcpp_sample main.cpp)
+
+# Check it works with the same target that conan users use
+target_link_libraries(btcpp_sample PRIVATE BT::behaviortree_cpp)

tests/export/target_link_libs/main.cpp

@@ -0,0 +1,78 @@
+// Copy of https://github.com/BehaviorTree/btcpp_sample/blob/main/main.cpp
+
+#include "behaviortree_cpp/bt_factory.h"
+
+using namespace BT;
+
+// clang-format off
+static const char* xml_text = R"(
+
+ <root BTCPP_format="4" >
+
+     <BehaviorTree ID="MainTree">
+        <Sequence name="root">
+            <AlwaysSuccess/>
+            <SaySomething   message="this works too" />
+            <ThinkWhatToSay text="{the_answer}"/>
+            <SaySomething   message="{the_answer}" />
+        </Sequence>
+     </BehaviorTree>
+
+ </root>
+ )";
+// clang-format on
+
+class SaySomething : public BT::SyncActionNode
+{
+  public:
+  SaySomething(const std::string& name, const BT::NodeConfig& config) :
+        BT::SyncActionNode(name, config)
+  {}
+
+  BT::NodeStatus tick() override
+  {
+    std::string msg;
+    getInput("message", msg);
+    std::cout << msg << std::endl;
+    return BT::NodeStatus::SUCCESS;
+  }
+
+  static BT::PortsList providedPorts()
+  {
+    return {BT::InputPort<std::string>("message")};
+  }
+};
+
+class ThinkWhatToSay : public BT::SyncActionNode
+{
+  public:
+  ThinkWhatToSay(const std::string& name, const BT::NodeConfig& config) :
+        BT::SyncActionNode(name, config)
+  {}
+
+  BT::NodeStatus tick() override
+  {
+    setOutput("text", "The answer is 42");
+    return BT::NodeStatus::SUCCESS;
+  }
+
+  static BT::PortsList providedPorts()
+  {
+    return {BT::OutputPort<std::string>("text")};
+  }
+};
+
+int main()
+{
+
+  BehaviorTreeFactory factory;
+
+  factory.registerNodeType<SaySomething>("SaySomething");
+  factory.registerNodeType<ThinkWhatToSay>("ThinkWhatToSay");
+
+  auto tree = factory.createTreeFromText(xml_text);
+
+  tree.tickWhileRunning();
+
+  return 0;
+}