Crystal: Hash with initial_capacity calls `resize`

[jgaskins]

I noticed while running the profiling for this post that GC#realloc was getting invoked during calls to Hash#resize, made while populating hashes that were created with an initial_capacity.

Here is a minimized repro:

class MyHash < Hash(Int32, Int32)
  def resize : Nil
    puts "Resizing, current_size: #{size}"
    super
  end
end

size = 1000
hash = MyHash.new(initial_capacity: size)
size.times { |i| hash[i] = i }
# => Resizing, current_size: 512
pp hash.size
# => 1000

Every hash size I've tested this against on current master calls resize, but it doesn't happen in 0.30.1 so it appears to be new behavior.

[asterite]

Good catch, thanks!

[oprypin]

Perhaps there should also be a spec that resize is not immediately called like shown in this example