Action: Add test for unstable Ruby VMs

[marcotc]

This PR runs the latest, still unstable, version of CRuby, JRuby, and TruffleRuby against our existing test suite.

I used GitHub Actions instead of CircleCI because there's not easy way to get bleeding edge Ruby images in CircleCI, while the GitHub Action ruby/setup-ruby has great support for it out of the box.

Luckily, they all the tests I could run pretty much pass, except for JRuby ruby/setup-ruby action being non-functional at this moment (not related to ddtrace). I've opened an issue description with the problem.

There was only a single fix required for Ruby 3.1 support as of today.

I did not attempt to run tests that depended on external services (MySQL, Redis, MongoDB, etc.), and stuck to the ones that only depend on Ruby code.

I'll leave this PR in draft until the JRuby issue gets traction.

[ivoanjo]

Since head may fail due to unrelated issues, what do you think of adding something like continue-on-error? (see [1, 2])

That would even enable us to merge this as-is now: JRuby is failing, no impact :)

[marcotc]

I come back to actions/runner#2347 every so often and it just makes me sad that there's no support for it as described 😢.

I guess we have not other way today, except completely hiding the output in case of error, but that's just GitHub actions I guess.

[codecov-commenter]

Codecov Report

Merging #1550 (53548dd) into master (b20dc3b) will decrease coverage by 0.00%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1550      +/-   ##
==========================================
- Coverage   98.24%   98.23%   -0.01%     
==========================================
  Files         878      878              
  Lines       42372    42372              
==========================================
- Hits        41627    41626       -1     
- Misses        745      746       +1     

Impacted Files	Coverage Δ
spec/ddtrace/span_spec.rb	100.00% <100.00%> (ø)
spec/ddtrace/profiling/ext/forking_spec.rb	99.38% <0.00%> (-0.62%)	⬇️

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[marcotc]

As documented in actions/runner#2347, the only way to get a green "total" CI outcome today, while allowing failures, is to add continue-on-error on a per-step basis. This also mean that the failure outcome of CI is hidden.

[ivoanjo]

As documented in actions/runner#2347, the only way to get a green "total" CI outcome today, while allowing failures, is to add continue-on-error on a per-step basis. This also mean that the failure outcome of CI is hidden.

Meh indeed. I wonder how difficult it would be to post those outcomes as a GitHub comment, or as a slack message, something like "Hey, this is low priority/non-blocking but your PR failed to build on whatever-head".

[ivoanjo]

LGTM 👍