Split gemfiles for each runtime

[TonyCTHsu]

Motivation:

The default behaviour for appraisal does not fit well with our requirements.

Our pain using appraisal

• Difficult to extend/customize appraisal behaviour in Appraisals file, because the self object is Appraisal::AppraisalFile already been evaluated.
• The DSL does not support eval_gemfile (which is important to split gemfiles for each ruby version)
• We are writing a lot of conditionals Gemfile at root, and creating gemfile symlink of each ruby version to avoid lockfile conflict.
• Each appraisal group become bloated and contain unnecessary dependencies
• bundle exec appraisal install returns false positive result about local gems satisfied the lockfile ends up missing dependencies.

What does this PR do?

• Copy the Gemfile at root to its own gemfile for each ruby runtime and eval_gemfile dynamically
• Create appraisal/generate.rb (wrapped with bundle exec rake dependency:generate to replace bundle exec appraisal generate) contains our customize logic and is equivalent with Appraisals.

We are still using appraisal in terms of gemfile formatting (bundle exec rake dependency:generate and bundle exec appraisal generate are creating the EXACT same content), hence the appraisal gem cannot be removed yet

The changes from this PR makes us easier to customize the behaviour for gemfiles, and opens up the possibility to trim down the bloated groups for scaling.

[pr-commenter]

Benchmarks

Benchmark execution time: 2024-11-14 03:51:19

Comparing candidate commit 4d537f3 in PR branch tonycthsu/split-gemfiles with baseline commit 2b8486e in branch master.

Found 0 performance improvements and 1 performance regressions! Performance is the same for 28 metrics, 2 unstable metrics.

scenario:tracing - Propagation - Datadog

• 🟥 throughput [-2857.293op/s; -2758.985op/s] or [-8.595%; -8.299%]

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.78%. Comparing base (7b5fef3) to head (4d537f3).
Report is 10 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4112      +/-   ##
==========================================
- Coverage   97.78%   97.78%   -0.01%     
==========================================
  Files        1350     1350              
  Lines       81063    81079      +16     
  Branches     4085     4085              
==========================================
+ Hits        79270    79282      +12     
- Misses       1793     1797       +4     

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[Strech]

LGTM 👍🏼