Add ruby-dev definition

[eregon]

• Currently the same as 3.3.0-dev but that name changes every year, so this makes it easy to install ruby dev/master.

I always wondered why this is missing, well, let's add it.
cc @nirvdrum who mentioned there is some non-trivial workaround at Shopify due to the lack of this.

[mislav]

I like that there is a definition that always means "Ruby master", but it also might be slightly confusing that we now have to identical definitions: ruby-dev and 3.3.0-dev (or whichever the latest MAJOR.MINOR version Ruby is at).

Could we set up ruby-dev as an alias that resolves to the latest MAJOR.MINOR.0-dev definition? I've also been meaning to set up ruby as an alias for the latest Ruby stable version, so it can be used as an easy way to install latest Ruby.

[eregon]

I think it's best to keep them separate, because e.g. once Ruby 3.3.0 is released the 3.3.0-dev file should be updated to use the ruby_3_3 branch, and maybe we forget to add 3.4.0-dev immediately or so. Or maybe even before the release, if CRuby uses a release branch or so (not the case so far though), then 3.3.0-dev would already change.

Specifically, ruby-dev should never need to change and always use master, while n.n.n-dev changes at least once.

There is also the question of whether it makes sense to even have e.g 3.4.0-dev before 3.4 is released, but that can be considered separately.

[eregon]

Aside: the naming 3.2.0-dev is pretty strange given there is 3.2.2 now, but 3.2.0-dev is newer than 3.2.2.
Maybe it should be 3.2-dev? (not something I want to change in this PR though)

[mislav]

Maybe it should be 3.2-dev?

Agreed. Maybe that's a naming scheme we could go for 3.4-dev onward.

[hsbt]

Agreed. Maybe that's a naming scheme we could go for 3.4-dev onward.

+1

How about this transition?

1. We add ruby-dev definition same as 3.3.0-dev with this PR.
2. We will add 3.4-dev after bumping ruby version to 3.4 on ruby/ruby repo. and update 3.3.0-dev to ruby_3_3 branch.
3. We will rename all of X.Y.0-dev to X.Y-dev.

[eregon]

Sounds good, I'll merge this then.

[mislav]

That all sounds great, thank you.

3. We will rename all of X.Y.0-dev to X.Y-dev.

Should the legacy names X.Y.0-dev still work with ruby-build going forward (for backwards compatibility), or is it fine if they error out? Since these are "dev" builds, I wouldn't mind breaking a few things in this transition. But yet again, I do not use these definitions regularly myself.

[eregon]

I think it's very rare to use X.Y-dev after X.Y.0 is out, so I think it'd be fine to break that, and if it proves to affect too many users then we could do some kind of aliasing.