Inconsistency with __dir__ in jar

[stergiom]

Environments

• jruby 9.1.10.0 (2.3.3) 2017-05-25 b09c48a Java HotSpot(TM) 64-Bit Server VM 25.131-b11 on 1.8.0_131-b11 +jit [darwin-x86_64]

• jruby 9.1.7.0 (2.3.1) 2017-01-11 68056ae Java HotSpot(TM) 64-Bit Server VM 25.131-b11 on 1.8.0_131-b11 +jit [darwin-x86_64]

Expected Behavior

When called inside of a jar __dir__ returns a jar relative path

Actual Behavior

Returns an os relative path + the jar relative path

Example:

puts "__dir__: #{__dir__}"
#=> __dir__: /Users/usr/dev/app/classpath:

puts "File.dirname(__FILE__): #{File.dirname(__FILE__)}"
#=> File.dirname(__FILE__): classpath:/

Additional info:
This affects use of the Dry-Validation gem here: https://github.com/dry-rb/dry-validation/blob/7a9897a806f9f6664a83567f48f5dc0acb739f04/lib/dry/validation/messages/abstract.rb#L13

[stergiom]

Just noticed this has already been reported in #4611