added Integer.try_convert, Ruby 3.1 support

[moste00]

Fixed an issue listed in #2733, namely the addition of a method try_convert to the class Integer, spec is in spec/ruby/core/integer/try_convert_spec.rb.

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[eregon]

Thank you for the PR, I will review after the OCA is through.

[eregon]

Thank you for the PR, I'll do the finishing touches and run the internal CI on it.

It also needs a changelog entry, I'll add it.

[eregon]

@moste00 Which ruby version did you use to get the error message?
I tried on CRuby 3.1.3 and the message used to, not into:

$ jt -u ruby test spec/ruby/core/integer/try_convert_spec.rb
ruby 3.1.3p185 (2022-11-24 revision 1a6b16756e) [x86_64-linux]
                                                                                             
1)
Integer.try_convert sends #to_int to the argument and raises TypeError if it's not a kind of Integer ERROR
Expected TypeError (can't convert MockObject into Integer (MockObject#to_int gives Object))
but got: TypeError (can't convert MockObject to Integer (MockObject#to_int gives Object))

[eregon]

The CI tells us in https://github.com/oracle/truffleruby/actions/runs/4347779724/jobs/7611599985
that in is used (Ruby < 3.1 doesn't run those specs of course).
So I'll change to that.

[moste00]

@moste00 Which ruby version did you use to get the error message? I tried on CRuby 3.1.3 and the message used to, not into:

I was having problems with my distro's apt when I added the specs testing the error message, it seemed to think that ruby 3.0 is the newest version and no amount of updating or upgrading will change its mind. As a temp workaround I used this website https://try.ruby-lang.org/, which, now that I have the idea to run "puts RUBY_VERSION", uses ruby 3.2 under the hood. I apologize for not noticing this earlier, and for not using my local 3.1 as soon as I got it working.

As a curious observation, CRuby changed the error message going from 3.1 to 3.2 without inlcuding this in the release docs or any other docs I'm aware of (or did they ?), the error message also appears to be inconsistent : in ruby 3.1, passing an Object.new that mocks :to_int to return an empty string gives the same standard message as any other non-Integer object (using "to"), but in ruby 3.2, the empty string in particular gets the response "no implicit conversion of Object into Integer", other strings and Object.new get the usual response with "into".

Maybe there is an official subtlety in the type system somewhere that says the empty string in particular should get this particular response, but more likely it seems to me that this is just an implementation detail. It seems also that CRuby doesn't regard error messages as part of the API, this might be an explanation for why nobody wrote a spec to test the message till now. So should we even regard error messages as API-visible changes when CRuby itself doesn't ? Is it plausible that someone is "depending" on the error message being this exact same string somehow ? I don't know, but I think it's low probability.

[eregon]

https://try.ruby-lang.org/ is using Opal and not CRuby, you can see that with:

p RUBY_DESCRIPTION
p RUBY_VERSION

And Opal is not fully compatible, e.g. they have a different message there.
I will try to find a way to change this, you're not the first one to fall into this trap.
ruby/TryRuby#122