Fix Ruby 3.3 SyntaxError caused by anonymous keyword argument forwarding

[cfe86]

Summary

Ruby 3.3 raises a SyntaxError when anonymous keyword rest parameters (**) are forwarded.
connection_pool was still forwarding anonymous keyword arguments in several places, which causes the gem to fail on Ruby 3.3.

This PR updates those method signatures to use named keyword rest parameters (**kwargs) and forwards them explicitly.

Impact

• No behavior changes
• No public API changes
• Ruby 3.0–3.3 compatible
• Fixes a parse-time SyntaxError on Ruby 3.3

Testing

Verified locally on Ruby 3.3. Before this change, loading bundle exec rake assets:precompile raised errors such as:

.../connection_pool-3.0.2/lib/connection_pool.rb:65: anonymous keyword rest parameter is also used within block (SyntaxError)

After the fix, the code compiles and loads correctly.

[mperham]

Why was CI passing with 3.3?

[cfe86]

@mperham honestly I’m not entirely sure why CI didn’t catch this. I ran into it while updating factory_bot 6.5.5 → 6.5.6, which indirectly upgraded connection_pool (2.5.5 → 3.0.2), and immediately hit:

.../connection_pool-3.0.2/lib/connection_pool.rb:65: anonymous keyword rest parameter is also used within block (SyntaxError)

After digging a bit, it turns out Ruby 3.3 raises a parse-time SyntaxError when anonymous keyword rest parameters (**) are forwarded.

My best guess is that the affected methods/files are lazily loaded, and the Ruby 3.3 CI doesn’t end up requiring them, so the file never gets parsed in CI. I didn’t verify the exact test coverage, but locally the error reproduces reliably as soon as the file is required.

[cfe86]

@mperham thanks for merging! Did a few more tests. For what it's worth. Seems to be a ruby 3.3.0 only problem: https://bugs.ruby-lang.org/issues/20090

Example

def test(**)
  [1].each do
    puts(**)
  end
end

test(a: 1)

def bar(*)
  [1].each do
    puts(*)
  end
end

bar('1')

Ruby 3.3.0:

ruby test.rb
test.rb: 
test.rb:3: anonymous keyword rest parameter is also used within block (SyntaxError)
test.rb:11: anonymous rest parameter is also used within block

Ruby 3.3.1

ruby test.rb
{:a=>1}
1

[mperham]

That explains it, thanks.