Add Ruby 3.0 Support - Delegation Methods

[haseebab]

Ruby 3.0 introduced the separation of positional and keyword arguments:

Handling argument delegation

Ruby 2.6 or prior

In Ruby 2, you can write a delegation method by accepting a *rest argument and a &block argument, and passing the two to the target method. In this behavior, the keyword arguments are also implicitly handled by the automatic conversion between positional and keyword arguments.

def foo(*args, &block)
  target(*args, &block)
end

Ruby 3

You need to explicitly delegate keyword arguments.

def foo(*args, **kwargs, &block)
  target(*args, **kwargs, &block)
end

Changes in this pull request

This is a proposal to update delegate methods in this codebase (non-exhaustive), where the explicit delegation of keyword arguments is warranted, as per the Ruby 3.0 guidelines.

[github-actions[bot]]

❌ @haseebab the signed-off-by was not found in the following 1 commits:

• https://github.com/instana/ruby-sensor/commit/6916d64db06e5ab61a6ebf1b136736eba1508c36: Use a double splat keyword rest argument, for all delegation methods

📝 What should I do to fix it?

All proposed commits should include a sign-off in their messages, ideally at the end.

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[Ferenc-]

Hi

Thank you for taking the initative on this! In general the existing test jobs with Ruby 2.7 pass fine, on Ruby 2.6 it appears that we have a breaking issue:

1. ::Instana.agent.spawn_background_thread is called in lib/instana.rb:18 which goes through
2. @delegate.public_send(mth, *args, **kwargs, &block) in lib/instana/backend/agent.rb:38 and here an extra argument is being passed on to the next frame:
3. spawn_background_thread in host_agent.rb:19 and that doesn't like that extra argument: wrong number of arguments (given 1, expected 0) (ArgumentError)

[haseebab]

Hi

Thank you for taking the initative on this! In general the existing test jobs with Ruby 2.7 pass fine, on Ruby 2.6 it appears that we have a breaking issue:

1. ::Instana.agent.spawn_background_thread is called in lib/instana.rb:18 which goes through
2. @delegate.public_send(mth, *args, **kwargs, &block) in lib/instana/backend/agent.rb:38 and here an extra argument is being passed on to the next frame:
3. spawn_background_thread in host_agent.rb:19 and that doesn't like that extra argument: wrong number of arguments (given 1, expected 0) (ArgumentError)

@Ferenc- I've read over the guidelines again, and there's a section on A compatible delegation that works on Ruby 2.6, 2.7 and Ruby 3.

I've added a new commit that utilizes Module#ruby2_keywords to support delegation across all ruby versions, as the guidelines recommend. I think all the test suites should pass now.

[Ferenc-]

Hi, Thank you for you for taking the initiative. We believe that the 3.0 support is complete, so I am closing this issue now. We can re-open if needed.