Cop idea: prefer String#bytesize over String#bytes#size

[viralpraxis]

I've seen some developers using some_string.bytes.size (or count/length) instead of the constant-time String#bytesize method.

In MRI there is no copy-on-write optimization for string/array conversion, so for large strings, the unnecessary array allocation could result in performance issues

require "objspace"

s = "a" * 1_000_000
initial = ObjectSpace.count_objects_size[:T_ARRAY]
b = s.bytes.count
p (ObjectSpace.count_objects_size[:T_ARRAY] - initial) / (1 << 10)

> 7812

I've opened #474 which will be finished if the idea accepted

[dvandersluis]

This makes sense as a cop to me. The link you included in the PR (https://github.com/fastruby/fast-ruby#remove-extra-spaces-or-other-contiguous-characters-code) doesn't mention bytesize though, is there another source?

[viralpraxis]

I copy-pasted it from another config entry, that Reference key is obsolete in this case

[viralpraxis]

The PR is ready for review