==: Fix to compare with address prefix

[taketo1113]

It fixes to compare with an address prefix for == method.
It return false when compared with a different address prefix.

IPAddr.new('10.0.0.0/16') == IPAddr.new('10.0.0.0/8')
=> false # changed behavior

IPAddr.new('10.0.0.0') == IPAddr.new('10.0.0.0')
=> true

IPAddr.new('10.0.0.0/16') == IPAddr.new('10.0.0.0/16')
=> true

Fix #21

[sorah]

I agree this is a bug but actually this behaviour is long-standing, so I'm slightly afraid of introducing incompatibility

[taketo1113]

I agree this is a bug but actually this behaviour is long-standing, so I'm slightly afraid of introducing incompatibility

@sorah Sure, It changes existing behavior.
Do you mean that would need major version up?

I think it needs to fix this bug even if changing behavior, because if not fix this bug for considered incompatibility, it will be a more serious incompatibility.

[knu]

The test case has been there since the very beginning, so I believe this behavior is as intended by the original author Umemoto-san.

I'd like to see a new strict equality method added rather than breaking compatibility.

[knu]

I think we already have eql? that can be used for strict equality test.

[taketo1113]

@knu Thanks for the comments.
I think too it is better to use eql? method, rather than add another method to compare addresses with prefix.

And I found the same issues in Ruby Issue Tracking System.
I’m going to close this PR.

• https://bugs.ruby-lang.org/issues/11531
• https://bugs.ruby-lang.org/issues/1905