What is the expected behaviour of BSON::Document#except when the arguments are symbols? I'm observing this behaviour

require 'bundler/inline'
gemfile do
  source 'https://rubygems.org'
  gem 'mongo', '2.14.0'
  gem 'bson', '4.11.1'
  gem 'activesupport', '~> 5.2'
end
require 'active_support/core_ext/hash'
require 'bson'
doc = BSON::Document.new("key" => "value")
doc.except(:key) #=> {}

require 'bundler/inline'
gemfile do
  source 'https://rubygems.org'
  gem 'mongo', '2.14.0'
  gem 'bson', '4.11.1'
  gem 'activesupport', '~> 6.0.3'
end
require 'active_support/core_ext/hash'
require 'bson'
doc = BSON::Document.new("key" => "value")
doc.except(:key) #=> {"key"=>"value"}

i.e. the behaviour depends on the version of activesupport loaded.

This looks to be because in 5.2 `except` in active support was implemented by duping the hash and then calling `delete` on all the passed arguments. Since {{BSON::Document }}implements delete to convert keys to strings, except inherits the behavior.

In rails 6, except is defined as

def except(*keys)
  slice(*self.keys - keys)
end

And so keys are not converted.

It would be straightforward to implement except directly on BSON::Document }}(and I'd be happy to do a PR for that){{ }}but this does at least come down in part to what should it do, since it many ways this is a another project's monkey patch to Hash causing issues (however in ruby 3 {{except is part of Hash)