RSpec makes define_method public?

[JonRowe]

Beats me, but I just stumbled upon a passing test that failed IRL because it used the private Module.define_method. Seems that after requiring RSpec, it's not private any more.

On Ruby v1.9.3 with RSpec v2.13:

>> Object.define_method
NoMethodError: private method `define_method' called for Object:Class
    from (irb):1
    from /usr/local/bin/irb:12:in `<main>'
>> require "rspec"
=> true
>> Object.define_method
ArgumentError: wrong number of arguments (0 for 1)
    from (irb):3:in `define_method'
    from (irb):3
    from /usr/local/bin/irb:12:in `<main>'

[thomas-holmes]

Looks like it is intentionally being made to be this way in memoization_helpers.rb:475

[myronmarston]

Looks like it is intentionally being made to be this way in memoization_helpers.rb:475

That's only making it public in an anonymous module, though. I don't think that affect Object, although I could be wrong...

Regardless, we should fix this. Thanks for reporting it!

[thomas-holmes]

I will try to look into it further, I'd like to help 👍

[thomas-holmes]

I tried defining another method in the same place that was private (method_undefined) and it became public on Object. I think that definitively makes this the culprit. Any suggestions on how to proceed containing this?

[moll]

Other than ditching Ruby? :) I'd say removing line 475 as the following holds true:

>> Object.define_method
NoMethodError: private method `define_method' called for Object:Class
        from (irb):1
        from /usr/local/bin/irb:12:in `<main>'
>> module Foo
>>   public_class_method :define_method
>> end
=> Foo
>> Object.define_method
ArgumentError: wrong number of arguments (0 for 1)
        from (irb):3:in `define_method'
        from (irb):3
        from /usr/local/bin/irb:12:in `<main>'

[myronmarston]

To me, it feels like a bug in ruby. Regardless, we should fix the code so it doesn't do this. The reason I had put public_class_method :define_method was to make it easy to define new methods on those modules, as that's basically the role they serve. We can remove that line and use send instead, though. Alternately, if you can find another way to make define_method public w/o it leaking....then have at it :).

[JonRowe]

I'm guessing public_class_method works on the original class it's defined on rather than the one we're creating, changing how we define the method as public (by redefining the method) works on the current class.

I've also added a test to ensure we don't leak it.

Review? /cc @myronmarston @samphippen @soulcutter

[moll]

Hehe, after reporting this I investigated how visibility works in Ruby and found out the public method applies only to instance methods of the current class and thereby does not apply to methods set on the singleton class. It's a nuts system because the public you, @JonRowe, added on line 475 is useless.

Which, on a side note, is probably a SNAFU everywhere where people expect methods defined via def self.foo following private to be private.

[myronmarston]

Thanks to both of you for working on this!

The spec added by @JonRowe is nice (we want specs for this kind of stuff to prevent regressions), but I think I prefer the simplicity of the @thomas-holmes's fix. I had originally made the method public as a convenience...but the solution of redefining define_method to make it public seems more complicated then just using send.

[JonRowe]

Ok I've picked across @thomas-holmes' fix, just rerunning the specs then I'll merge it.

[myronmarston]

@JonRowe -- thanks! Please add a changelog entry, too.

[thomas-holmes]

Thanks guys!

[myronmarston]

So this is interesting:

https://bugs.ruby-lang.org/issues/8284

I started a discussion on the ruby rogues mailing list about this, someone reporte the bug to the ruby issue tracker and it got fixed. Turns out it's been a bug in MRI since ruby 1.0.

[JonRowe]

I liked this bit

I don't know if it will be, but in any case there is always
`singleton_class.send :public, :define_method`
instead or equivalent.

It's a bit more clear, IMO, as using "public_class_method" on a Module is a bit strange...
Modules don't really have "class methods".

FWIW, there are no specs in RubySpec about "public_class_method" on a Module.