Favoring explicit class declaration

[jeremyf]

What type of PR is this? (check all applicable)

• Refactor

Description

In helping track down #17041 I was looking at our cache
busting logic. We were looking up a constant via the .const_get call
from a string already defined inline. This refactor short-circuits
naming a string, capitalizing it, then looking in the class's registered
constants.

There's also a subtle bug in the original; When provider equals
"another_cache", the #capitalize method would return
"Another_cache", whereas #classify will return "AnotherCache".

Below are some benchmarks for the change.

require "benchmark"

module EdgeCache
  class Bust
    def by_class
      Fastly
    end

    def by_const_get
      self.class.const_get("fastly".classify)
    end
  end
end

Benchmark.bmbm do |x|
  x.report("by_class") do
    1000.times do
      EdgeCache::Bust.new.by_class
    end
  end
  x.report("by_const_get") do
    1000.times do
      EdgeCache::Bust.new.by_const_get
    end
  end
end

> bin/rails runner /Users/jfriesen/git/forem/bench.rb

Rehearsal ------------------------------------------------
by_class       0.001239   0.000186   0.001425 (  0.001342)
by_const_get   0.011398   0.000136   0.011534 (  0.011538)
--------------------------------------- total: 0.012959sec

                   user     system      total        real
by_class       0.000973   0.000030   0.001003 (  0.000969)
by_const_get   0.011102   0.000032   0.011134 (  0.011104)

Related Tickets & Documents

QA Instructions, Screenshots, Recordings

None, this is already tested.

UI accessibility concerns?

None.

Added/updated tests?

• No, and this is why:

[Forem core team only] How will this change be communicated?

• I will share this change internally with the appropriate teams