Fixed parentPath() return when input has no parent

[jennuine]

🦟 Bug fix

Summary

With the parentPath updates from #238 , parentPath returns an empty string when there is no parent. This caused INTEGRATION_camera_video_record_system test to fail. I added a fix to match the behavior from ign-common5. Feel free to close if ign-gazebo's CameraVideoRecorder should be fixed instead.

Also, fixed some codecheck errors. I wonder why it's not being picked up by our linters?

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
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[codecov]

Codecov Report

Merging #307 (ea1e723) into main (e79b31f) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #307   +/-   ##
=======================================
  Coverage   76.75%   76.75%           
=======================================
  Files          75       75           
  Lines       10325    10327    +2     
=======================================
+ Hits         7925     7927    +2     
  Misses       2400     2400           

Impacted Files	Coverage Δ
src/Timer.cc	100.00% <ø> (ø)
src/Util.cc	84.23% <ø> (ø)
src/Filesystem.cc	96.15% <100.00%> (+0.06%)	⬆️

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[mjcarroll]

I added a fix to match the behavior from ign-common5. Feel free to close if ign-gazebo's CameraVideoRecorder should be fixed instead.

Nope, this is correct. I would like to keep this as compatible as possible with ign-common5. Ideally, going forward, developers also have access to std::filesystem to use for other implementations if they would like.

[mjcarroll]

I wonder why it's not being picked up by our linters?

That I don't know. I know that I generally can't run cppcheck without a bunch of false positives on focal, but the bionic CI usually keeps me honest?