Prefer empty() over size() when checking container state

[SunBlack]

Changes are done by run-clang-tidy -header-filter='.*' -checks='-*,readability-container-size-empty' -fix

[SergioRAgostinho]

Would it be possible to perform a find-replace to change from empty() to empty (). Because as it is, we are accepting a PR that breaks PCL's coding style with every change it introduced :/

[SunBlack]

Would it be possible to perform a find-replace to change from empty() to empty (). Because as it is, we are accepting a PR that breaks PCL's coding style with every change it introduced :/

Well if I replace all .empty() by .empty (), this will be 389 changes. You really want this in this PR?

Btw: This is the part of the coding style that I really don't like at all. I don't have an idea until now, which benefit we got by a whitespace before a bracket (for me it decreases readability).

[SunBlack]

Ups wrong button, didnt' wanted to close this PR xD

[taketwo]

Yes, this whitespace was a notorious choice for the style guide. (Not made by any of us who are currently active in PCL.) I think when we finally adopt automatic code formatting tools we can change it. But we have to live with it, at least for now.

[SergioRAgostinho]

Well if I replace all .empty() by .empty (), this will be 389 changes. You really want this in this PR?

Thank you for the sanity check ^^ Once we get the formatting tool running on CI I'm open to discuss changes to the style guide.