repro.rb

require "bundler/inline"

gemfile do
  source "https://rubygems.org"

  ruby "2.7.8" # keyword-hash deprecation warnings

  gem "concurrent-ruby", "1.3.3"
end

Warning[:deprecated] = true # must be enabled
Warning.extend(
  Module.new do
    def warn(msg) # overridden to log Ruby warnings same as Rails warnings
      puts msg
      Thread.pass # simulates ActiveSupport::Dependencies.warn as we used in production to log instances of deprecations
    end
  end
)

class Kaka
  def provide(input:)
    input.fetch("claim_id")
  end
end

class Dudu
  def provide(input:)
    _claim_id = input.fetch("claim_id") # assignment to make it different frm Kaka#provide
  end
end

pending_promises =
  [Kaka.new, Dudu.new].map do |provider|
    Concurrent::Promises.future do
      provider.provide({ input: { "claim_id" => "LPC009-639-035" } }) # pass hash to keywords, incorrectly but still allowed in 2.7
    end
  end

sleep(1) # wait a moment to resolve futures

pp(pending_promises)

# ➜  ruby-2-7-keywords-futures git:(repro) ✗ ruby repro.rb
# repro.rb:36: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
# repro.rb:36: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
# repro.rb:22: warning: The called method `provide' is defined here
# repro.rb:28: warning: The called method `provide' is defined here
# [#<Concurrent::Promises::Future:0x000000012d0ba148 rejected with #<NoMethodError: undefined method `fetch' for #<Kaka:0x000000012d0bb138>>>,
#  #<Concurrent::Promises::Future:0x000000012d0b8578 fulfilled with "LPC009-639-035">]
#
# ➜  ruby-2-7-keywords-futures git:(repro) ✗ ruby repro.rb
# repro.rb:36: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
# repro.rb:36: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
# repro.rb:28: warning: The called method `provide' is defined here
# repro.rb:22: warning: The called method `provide' is defined here
# [#<Concurrent::Promises::Future:0x000000012c846818 fulfilled with "LPC009-639-035">,
#  #<Concurrent::Promises::Future:0x000000012c844a90 rejected with #<NoMethodError: undefined method `fetch' for 0:Integer>>]