Use Module.prepend instead of alias_method for Range#to_s

[imanel]

This is a follow-up pull request to #19434 - now that Ruby 2.2.2 is out we can switch to #prepend.

Looks like to_formatted_s and to_default_s are neither mentioned, nor tested, so we can treat them as private API that was required for alias_method_chain - but deprecation warning is left just in case.

/cc @rafaelfranca @kirs @sgrif

[rails-bot]

r? @kaspth

(@rails-bot has picked a reviewer for you, use r? to override)

[kaspth]

Think the old explanation was clearer.

[kaspth]

Looks good to me. Keep your commits squashed to 1, after fixing my one comment, and I'll merge.

[imanel]

Fixed as in comment.

[jeremy]

Is to_formatted_s public API, or an implementation detail? Should it be deprecated, or preserved?

Note that all core_ext/*/conversions.rb follow the same pattern (to_formatted_s as public API that's aliased to to_s) so we'll want to address them all together.

[rafaelfranca]

Is to_formatted_s public API, or an implementation detail? Should it be deprecated, or preserved?

It is a public API since we are documenting it. In my opinion it should be preserved since its implementation is not hard and we are not using any deprecated API like alias_method_chain to implement it.

[imanel]

There was discussion about this topic in #20038 (same issue with Numeric type). I believe to_formatted_s was here only because of alias_method_chain (not used here directly for naming convention). It isn't tested anywhere and it's not even mentioned in core extensions document. to_default_s wasn't even mentioned in documentation.

[kaspth]

On the other hand, if all the deprecations are as simple as deprecate to_default_s: :to_s, to_formatted_s: :to_s, I'd say we might as well go for it.

[imanel]

Any updates on this one?

[kaspth]

I'm 👍 on deprecations, but, like @jeremy said, they should be handled together.

Can you take the deprecation out?

[imanel]

Removed deprecation of to_formatted_s, but to_default_s is still there. Should I remove it too?

[kaspth]

Yes, to_default_s is public API and should be deprecated in another PR with the other similar aliases.

[imanel]

Ok - all deprecations removed as requested.

[kaspth]

Thanks, will you be following this up with a deprecation PR?

[imanel]

Thanks for merging. I will try to do follow-up PR this weekend.