Draft: Capture args by reference instead of copy (!394) · Merge requests · Software / ArmarX / RobotAPI

Rainer Kartmann requested to merge feature/passing-non-const-ref-to-skill-factory into master Oct 23, 2023

I have skills that were initialized with connectTo(armarx::armem::client::MemoryNameSystem& mns) function after creation. Note that the mns is passed by reference to allow subscriptions etc. (see https://git.h2t.iar.kit.edu/research-projects/jubot/demo/-/merge_requests/11)

I updated them now to the changes in the skill framework. This lead to the skill receiving the MNS reference via constructor, and the component passing the MNS reference via the addSkillFactory<>() function.

Currently, this leads to

error message

In file included from /usr/include/c++/8/memory:80,
                 from /home/.../armarx/ArmarXCore/source/ArmarXCore/core/logging/LoggingUtil.h:26,
                 from /home/.../armarx/ArmarXCore/source/ArmarXCore/core/logging/LogSender.h:28,
                 from /home/.../armarx/ArmarXCore/source/ArmarXCore/core/logging/Logging.h:30,
                 from /home/.../armarx/ArmarXCore/source/ArmarXCore/core/ManagedIceObject.h:31,
                 from /home/.../armarx/ArmarXCore/source/ArmarXCore/core/Component.h:28,
                 from /home/.../h2t/research_projects/jubot/demo/source/jubot/demo/components/personalized_dialog_skills/Component.h:29,
                 from /home/.../h2t/research_projects/jubot/demo/source/jubot/demo/components/personalized_dialog_skills/Component.cpp:24:
/usr/include/c++/8/bits/unique_ptr.h: In instantiation of ‘typename std::_MakeUniq<_Tp>::__single_object std::make_unique(_Args&& ...) [with _Tp = jubot::demo::personalized_dialog::skills::Hello; _Args = {const armarx::armem::client::MemoryNameSystem&}; typename std::_MakeUniq<_Tp>::__single_object = std::unique_ptr<jubot::demo::personalized_dialog::skills::Hello, std::default_delete<jubot::demo::personalized_dialog::skills::Hello> >]’:
/home/.../armarx/RobotAPI/source/RobotAPI/libraries/skills/provider/SkillFactory.h:36:56:   required from ‘static std::unique_ptr<armarx::skills::SkillBlueprint> armarx::skills::SkillBlueprint::ForSkill(Args&& ...) [with _Skill = jubot::demo::personalized_dialog::skills::Hello; Args = {armarx::armem::client::MemoryNameSystem&}]’
/home/.../armarx/RobotAPI/source/RobotAPI/libraries/skills/provider/SkillProviderComponentPlugin.h:62:64:   required from ‘armarx::skills::SkillBlueprint* armarx::plugins::SkillProviderComponentPlugin::addSkillFactory(Args&& ...) [with SkillT = jubot::demo::personalized_dialog::skills::Hello; Args = {armarx::armem::client::MemoryNameSystem&}]’
/home/.../armarx/RobotAPI/source/RobotAPI/libraries/skills/provider/SkillProviderComponentPlugin.h:184:79:   required from ‘armarx::skills::SkillBlueprint* armarx::SkillProviderComponentPluginUser::addSkillFactory(Args&& ...) [with SkillT = jubot::demo::personalized_dialog::skills::Hello; Args = {armarx::armem::client::MemoryNameSystem&}]’
/home/.../h2t/research_projects/jubot/demo/source/jubot/demo/components/personalized_dialog_skills/Component.cpp:72:43:   required from here
/usr/include/c++/8/bits/unique_ptr.h:835:30: error: binding reference of type ‘armarx::armem::client::MemoryNameSystem&’ to ‘const armarx::armem::client::MemoryNameSystem’ discards qualifiers
     { return unique_ptr<_Tp>(new _Tp(std::forward<_Args>(__args)...)); }
                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /home/.../h2t/research_projects/jubot/demo/source/jubot/demo/components/personalized_dialog_skills/Component.cpp:34:
/home/.../h2t/research_projects/jubot/demo/source/jubot/demo/personalized_dialog/skills/Hello.h:28:9: note:   initializing argument 1 of ‘jubot::demo::personalized_dialog::skills::Hello::Hello(armarx::armem::client::MemoryNameSystem&)’
         Hello(armarx::armem::client::MemoryNameSystem& mns);
         ^~~~~
In file included from /usr/include/c++/8/memory:80,
                 from /home/.../armarx/ArmarXCore/source/ArmarXCore/core/logging/LoggingUtil.h:26,
                 from /home/.../armarx/ArmarXCore/source/ArmarXCore/core/logging/LogSender.h:28,
                 from /home/.../armarx/ArmarXCore/source/ArmarXCore/core/logging/Logging.h:30,
                 from /home/.../armarx/ArmarXCore/source/ArmarXCore/core/ManagedIceObject.h:31,
                 from /home/.../armarx/ArmarXCore/source/ArmarXCore/core/Component.h:28,
                 from /home/.../h2t/research_projects/jubot/demo/source/jubot/demo/components/personalized_dialog_skills/Component.h:29,
                 from /home/.../h2t/research_projects/jubot/demo/source/jubot/demo/components/personalized_dialog_skills/Component.cpp:24:
/usr/include/c++/8/bits/unique_ptr.h: In instantiation of ‘typename std::_MakeUniq<_Tp>::__single_object std::make_unique(_Args&& ...) [with _Tp = jubot::demo::personalized_dialog::skills::LearnCurrentPerson; _Args = {const armarx::armem::client::MemoryNameSystem&, const std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&}; typename std::_MakeUniq<_Tp>::__single_object = std::unique_ptr<jubot::demo::personalized_dialog::skills::LearnCurrentPerson, std::default_delete<jubot::demo::personalized_dialog::skills::LearnCurrentPerson> >]’:
/home/.../armarx/RobotAPI/source/RobotAPI/libraries/skills/provider/SkillFactory.h:36:56:   required from ‘static std::unique_ptr<armarx::skills::SkillBlueprint> armarx::skills::SkillBlueprint::ForSkill(Args&& ...) [with _Skill = jubot::demo::personalized_dialog::skills::LearnCurrentPerson; Args = {armarx::armem::client::MemoryNameSystem&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&}]’
/home/.../armarx/RobotAPI/source/RobotAPI/libraries/skills/provider/SkillProviderComponentPlugin.h:62:64:   required from ‘armarx::skills::SkillBlueprint* armarx::plugins::SkillProviderComponentPlugin::addSkillFactory(Args&& ...) [with SkillT = jubot::demo::personalized_dialog::skills::LearnCurrentPerson; Args = {armarx::armem::client::MemoryNameSystem&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&}]’
/home/.../armarx/RobotAPI/source/RobotAPI/libraries/skills/provider/SkillProviderComponentPlugin.h:184:79:   required from ‘armarx::skills::SkillBlueprint* armarx::SkillProviderComponentPluginUser::addSkillFactory(Args&& ...) [with SkillT = jubot::demo::personalized_dialog::skills::LearnCurrentPerson; Args = {armarx::armem::client::MemoryNameSystem&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&}]’
/home/.../h2t/research_projects/jubot/demo/source/jubot/demo/components/personalized_dialog_skills/Component.cpp:74:93:   required from here
/usr/include/c++/8/bits/unique_ptr.h:835:30: error: binding reference of type ‘armarx::armem::client::MemoryNameSystem&’ to ‘const armarx::armem::client::MemoryNameSystem’ discards qualifiers
     { return unique_ptr<_Tp>(new _Tp(std::forward<_Args>(__args)...)); }
                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /home/.../h2t/research_projects/jubot/demo/source/jubot/demo/components/personalized_dialog_skills/Component.cpp:35:
/home/.../h2t/research_projects/jubot/demo/source/jubot/demo/personalized_dialog/skills/LearnCurrentPerson.h:29:9: note:   initializing argument 1 of ‘jubot::demo::personalized_dialog::skills::LearnCurrentPerson::LearnCurrentPerson(armarx::armem::client::MemoryNameSystem&, const string&)’
         LearnCurrentPerson(armarx::armem::client::MemoryNameSystem& mns,
         ^~~~~~~~~~~~~~~~~~

which is fixed by this MR.

However, this requires that the passed arguments exist as long as the skill can be created, which might be non-obvious. So I am not sure whether we should keep this.

@peller @dreher Do you have ideas/opinions on this situation?

Draft: Capture args by reference instead of copy

Merge request reports