v2.2.1 warning: already initialized constant JWT Error

[jychen7]

Background

when we upgrade from 2.1.0 to 2.2.1, we receive a lot of warnings about "already initialized constant JWT Error" when start rails or simply run rails c
all errors inside this are shown

ruby-jwt/lib/jwt/error.rb

Lines 3 to 20 in f4c7f15

	module JWT
	EncodeError = Class.new(StandardError)
	DecodeError = Class.new(StandardError)
	RequiredDependencyError = Class.new(StandardError)
	VerificationError = Class.new(DecodeError)
	ExpiredSignature = Class.new(DecodeError)
	IncorrectAlgorithm = Class.new(DecodeError)
	ImmatureSignature = Class.new(DecodeError)
	InvalidIssuerError = Class.new(DecodeError)
	InvalidIatError = Class.new(DecodeError)
	InvalidAudError = Class.new(DecodeError)
	InvalidSubError = Class.new(DecodeError)
	InvalidJtiError = Class.new(DecodeError)
	InvalidPayload = Class.new(DecodeError)
	JWKError = Class.new(DecodeError)
	end

I think it is related to use first-class object short hand
c0b4c59
and

ruby-jwt/lib/jwt.rb

Line 8 in f4c7f15

require 'jwt/error'

ruby-jwt/lib/jwt/claims_validator.rb

Line 1 in faaa3a1

require_relative './error'

Expect

git checkout v2.1.0

irb
2.4.0 :001 > require 'jwt/error'
 => true
2.4.0 :002 > require_relative './lib/jwt/error'
 => true

Actual

git checkout v2.2.1

irb
2.4.0 :001 > require 'jwt/error'
 => true
2.4.0 :002 > require_relative './lib/jwt/error'
~/Documents/github/ruby-jwt/lib/jwt/error.rb:5: warning: already initialized constant JWT::DecodeError
~/.rvm/gems/ruby-2.4.0/gems/jwt-1.5.6/lib/jwt/error.rb:3: warning: previous definition of DecodeError was here
~/Documents/github/ruby-jwt/lib/jwt/error.rb:8: warning: already initialized constant JWT::VerificationError
~/.rvm/gems/ruby-2.4.0/gems/jwt-1.5.6/lib/jwt/error.rb:4: warning: previous definition of VerificationError was here
~/Documents/github/ruby-jwt/lib/jwt/error.rb:9: warning: already initialized constant JWT::ExpiredSignature
~/.rvm/gems/ruby-2.4.0/gems/jwt-1.5.6/lib/jwt/error.rb:5: warning: previous definition of ExpiredSignature was here
~/Documents/github/ruby-jwt/lib/jwt/error.rb:10: warning: already initialized constant JWT::IncorrectAlgorithm
~/.rvm/gems/ruby-2.4.0/gems/jwt-1.5.6/lib/jwt/error.rb:6: warning: previous definition of IncorrectAlgorithm was here
~/Documents/github/ruby-jwt/lib/jwt/error.rb:11: warning: already initialized constant JWT::ImmatureSignature
~/.rvm/gems/ruby-2.4.0/gems/jwt-1.5.6/lib/jwt/error.rb:7: warning: previous definition of ImmatureSignature was here
~/Documents/github/ruby-jwt/lib/jwt/error.rb:12: warning: already initialized constant JWT::InvalidIssuerError
~/.rvm/gems/ruby-2.4.0/gems/jwt-1.5.6/lib/jwt/error.rb:8: warning: previous definition of InvalidIssuerError was here
~/Documents/github/ruby-jwt/lib/jwt/error.rb:13: warning: already initialized constant JWT::InvalidIatError
~/.rvm/gems/ruby-2.4.0/gems/jwt-1.5.6/lib/jwt/error.rb:9: warning: previous definition of InvalidIatError was here
~/Documents/github/ruby-jwt/lib/jwt/error.rb:14: warning: already initialized constant JWT::InvalidAudError
~/.rvm/gems/ruby-2.4.0/gems/jwt-1.5.6/lib/jwt/error.rb:10: warning: previous definition of InvalidAudError was here
~/Documents/github/ruby-jwt/lib/jwt/error.rb:15: warning: already initialized constant JWT::InvalidSubError
~/.rvm/gems/ruby-2.4.0/gems/jwt-1.5.6/lib/jwt/error.rb:11: warning: previous definition of InvalidSubError was here
~/Documents/github/ruby-jwt/lib/jwt/error.rb:16: warning: already initialized constant JWT::InvalidJtiError
~/.rvm/gems/ruby-2.4.0/gems/jwt-1.5.6/lib/jwt/error.rb:12: warning: previous definition of InvalidJtiError was here
~/Documents/github/ruby-jwt/lib/jwt/error.rb:17: warning: already initialized constant JWT::InvalidPayload
~/.rvm/gems/ruby-2.4.0/gems/jwt-1.5.6/lib/jwt/error.rb:13: warning: previous definition of InvalidPayload was here
 => true