Re: [PATCH] Update respond_to? calls for second argument.

[Pat Allan <pat@freelancing-gods.com>]

For reference, here’s the point where Rack became explicit about using the two arguments:
https://github.com/rack/rack/commit/5f808aa2099841e5daec6cb772a304797879ce6c

I’m not quite sure where to start with a test, I’m afraid - so if you’re able to take care of that, that’d be brilliant.

As for the C internals - I’m reading what you’ve noted, and I’m understanding at a basic level, but you’ve got the deep knowledge here, so I’m very happy to go with your decisions :)

> On 21 May 2017, at 2:54 pm, Eric Wong <e@80x24.org> wrote:
> 
> Actually, there's also a rb_obj_respond_to API in Ruby 1.9+
> which could be used.  It's declared in ruby/intern.h which is a
> grey area as far as continued API support goes, and it's not
> documented in doc/extension.rdoc, either.
> 
> However, there is a rubyspec CAPI test for it; and I'm not sure
> the two-arg form of respond_to? is actually used by real Rack
> servers.
> 
> 
> Sidenote: rb_funcall* functions are always a bit slower since
> they need to go through method lookup before dispatch, and can't
> benefit from inline method caching, only global method caching.