From: janosch-x via ruby-core <ruby-core@...>
Date: 2024-01-07T15:12:34+00:00
Subject: [ruby-core:116061] [Ruby master Bug#20158] Ractor affects Coverage results

Issue #20158 has been reported by janosch-x (Janosch M�ller).



----------------------------------------

Bug #20158: Ractor affects Coverage results

https://bugs.ruby-lang.org/issues/20158



* Author: janosch-x (Janosch M�ller)

* Status: Open

* Priority: Normal

* ruby -v: ruby 3.3.0preview1 (2023-05-12 master a1b01e7701) [arm64-darwin22]

* Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN

----------------------------------------

I have a large rspec test suite. I found that if I call a Ractor, the Coverage results are strongly affected, i.e. almost all files appear to be uncovered. This happens even if I only ever call a Ractor before the library or rspec are required.



Unfortunately, I was not able to build a simple repro yet.



I assume it is a timing thing and only affects larger suites, or it only happens if there are multiple files, and maybe if the library lazily requires its sub-modules?



However, I guess this should produce the same results when added to the spec_helper.rb of other large suites:



```ruby

# Ractor.new { nil } # uncomment this to affect coverage results



require 'coverage'

Coverage.start



# require library, set up rspec etc. 



RSpec.configuration.after(:suite) do

  # this number is greatly reduced and unstable when calling Ractor above

  p Coverage.result.values.sum { |arr| arr.sum(&:to_i) }

end

```



I had this problem in [this library](https://github.com/jaynetics/character_set/). The problem affects simplecov users as well, as described [here](https://github.com/simplecov-ruby/simplecov/issues/1058).







-- 

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