Drop Ruby 2.5 support

[st0012]

Because Ruby 2.5 has reached EOL for more than 1.5 years and it won't be supported by the next reline version either.

[st0012]

cc @peterzhu2118

[peterzhu2118]

Looks good!

[peterzhu2118]

I realize that this isn't the fault of this PR, but the indentation of these lines look odd. Could you fix it?

[hsbt]

Is there any reason why remove Ruby 2.5 without EOL status? I prefer to keep the old Ruby until we use new feature of the recent Ruby versions or hard to maintain CI status.

[peterzhu2118]

I'm not sure what you mean. Ruby 2.5 was EOL as of March 2021. CI currently doesn't run with IRB master + reline master because tests fail, so the next release of reline will make tests fail.

[hsbt]

@peterzhu2118 I'm not against this change strongly. But I have a concern that you and @st0012 change reline and irb with the incompatible changes like the support version without maintainer who are @aycabta approval.

I know @aycabta is inactive today. But we should wait for him first. Can you wait until RubyKaigi 2022?

[st0012]

@hsbt To be clear, I didn't drop the 2.5 support on reline. It's done in this commit, which is required by relines's own dependency io-console.
So I'm just making sure irb will work with its own dependencies.

[st0012]

@hsbt I can understand your concern on the incompatible changes and I want to make it clear that

• I have no intention to disrespect @aycabta's great work nor the fact that he's these projects' maintainer
• I don't want to design and push these changes on my own either. That's why in my reline PRs and [PoC] Support dialog theme/color configuration #380 I also asked you and @nobu's opinions

I also want to explain why I'm pushing the recent changes now:

1. The background color issue on autocompletion affects many developers. There are at least 2 issues opened (Change default completion background color #328 and Default behavior change ( AUTOCOMPLETE, COLORIZE ) #351) with a dozen of comments talking about it. I also have seen multiple "tips" about disabling the feature altogether because it's distracting to developers (example). And I'm also bothered by this issue.
2. The reline APIs we recently introduced to address the issue were originally proposed last December. And it took us more than 2 months (from May to July) to review it and polish the APIs in follow up PRs.
3. So if we continue the work with the current pace, we'll probably be able to solve the issue (release reline, adopt the APIs in irb, finish documents...etc.) by October. And that only leaves us 2 months to let the community test it before we cut a new irb release and make it ship with Ruby 3.2.

So I hope you can understand that:

1. @peterzhu2118 and I only focus on this issue and try to make as few as breaking changes as possible. As I said, this PR is just to make irb support the same Ruby version as reline and io-console.
2. We are not rushing it. We just want to make sure we have time to make the solution great and tested for Ruby 3.2.

So back to your question:

I know @aycabta is inactive today. But we should wait for him first. Can you wait until RubyKaigi 2022?

Yes we can wait, including this PR, #380 and reline's release.

But IMO, a better option is to have a solution in irb master by RubyKaigi and ask Rubyists to test it and help us improve the solution before the Ruby release.

[hsbt]

@st0012 Thanks for clarification. I meant ruby/reline#456 (comment) as incompatible change.

Yes we can wait, including this PR, #380 and reline's release.

Also, Thanks. You and @peterzhu2118 's work are great too.

[st0012]

I meant ruby/reline#456 (comment) as incompatible change.

@hsbt I don't think that's an incompatible change because the original APIs haven't been released yet?

The latest reline is 0.3.1, which was made at Jan 2. Nothing made after that, including the dialog APIs by @pocari, has been released.

[hsbt]

Ah, I see.

[st0012]

@hsbt Since we have now clarified that:

1. We didn't drop Ruby 2.5 unnecessarily
2. We didn't make any incompatible changes

Do we still have to wait for @aycabta? As I said, we can wait, but I also want to see if there's any alternatives than just waiting.

For example, if you worry about us not knowing what not to change, I can reassure you that we are fully aware of the importance of compatibility as shown in the above comments.

Or if you worry about @aycabta won't be able to keep up with the changes, I'll be happy to document changes happened after this Feb when he's back (including changes made by other contributors). I'm happy to have a call to walk through them as well.

I think the best way to make great tools is to keep the development and feedback loop going. Because many user experience issues like this take time to surface and solutions also take time to experiment/polish.

[hsbt]

1. We didn't drop Ruby 2.5 unnecessarily

Yes. But It's IMO.

2. We didn't make any incompatible changes

I say it's maintainer's convenience. And my mainly concerns are you and @peterzhu2118 changes irb and reline without @aycabta 's opinion in this year.

[hsbt]

Unfotunately, We couldn't get @aycabta 's opinion. I decide to coordinate the next irb release for Ruby 3.2 final release.