[Windows][melodic-devel] Use boost::filesystem::path::string() to return std::string.

[seanyen]

On Windows, boost::filesystem::path::native() will return std::wstring while the code expects std::string, thus I replaced the native() usage with string() to accommodate it.

[welcome]

Thanks for helping in improving MoveIt!

[seanyen]

@rhaschke Hi Robert! Before I send other Windows-related pull requests, I'd like to check with you first how would you love to proceed the Windows related PRs? Do you want to follow the similar way we did for rivz? Like you create a branch to stage all Windows changes first?

And you can take a quick glance of this diff to feel the change scope: https://github.com/ros-planning/moveit/compare/melodic-devel...ms-iot:windows_fix?expand=1

[rhaschke]

LGTM. Thanks for your efforts bringing MoveIt to Windows!

[rhaschke]

Do you like you create a branch to stage all Windows changes first?

Yes. Indeed, I would prefer to have a windows-port branch for this. I have created an appropriate branch (feature-windows-port). As you originally targeted melodic-devel, please rebase your work onto master and direct PRs to the feature-windows-port branch. We will probably not back-port those changes to melodic-devel.

[rhaschke]

@seanyen, maybe you can join our next maintainer meeting and discuss with all of us how to proceed?
@davetcoleman, could you officially invite him and provide exact times? I'm not sure I will join, because I'm in holidays...

[davetcoleman]

@seanyen I just invited you, but also, its public now: https://discourse.ros.org/t/moveit-maintainer-meeting-all-invited-july-25th/9899/3

[v4hn]

For all patches that add overhead, such as #ifdefs, please use the separate feature-windows-support branch.

However, for all patches that amount to fixing API problems in MoveIt (e.g. not using the correct cmake installation variables, assuming native() always returns string, ...) I don't see a reason to scope them together with "windows-support" as they might also break at some point for other systems.
I also don't see a reason not to backport such changes to melodic as bug-fixes,
so I will merge this request and forward-port to master

[welcome]

Congrats on getting your first MoveIt! pull request merged and improving open source robotics!

[rhaschke]

@v4hn, we wanted to merge this into windows-port related feature branch...

[v4hn]

@rhaschke please see my reasoning above.

Also this request got two approvals.

[rhaschke]

I see. My reasoning was to group all related changes together... This could facilitate future adaptions in other contexts/projects, because we can just look what kind of changes were required here.

[v4hn]

That would make sense too. I expected the motivation to be an easy way to revert all windows-specific overhead (by reverting the merge commit) if necessary / of interest for a project.
In that case API fixes and cleanups should still stay...

[v4hn]

I would instead propose to track a list of such patches elsewhere (maybe in a separate issue)?