Address PR comments, and undo simplecov patch

.github/workflows/test-macos.yaml

@@ -43,5 +43,5 @@ jobs:
           bundler: 2.3.26 # needed to fix issue with steep on Ruby 3.0/3.1
       - run: bundle install
       - if: ${{ matrix.ruby == '3.4' }}
-        run: gem update --system 3.5.21
+        run: gem update --system 3.5.21 # the latest gem causes 3.4 macos failues
       - run: bundle exec rake spec:main

Gemfile

@@ -36,11 +36,7 @@ gem 'rspec_junit_formatter', '>= 0.5.1'
 # Merging branch coverage results does not work for old, unsupported rubies and JRuby
 # We have a fix up for review, https://github.com/simplecov-ruby/simplecov/pull/972,
 # but given it only affects unsupported version of Ruby, it might not get merged.
-if RUBY_VERSION.start_with?('3.4.')
-  gem 'simplecov'
-else
-  gem 'simplecov', git: 'https://github.com/DataDog/simplecov', ref: '3bb6b7ee58bf4b1954ca205f50dd44d6f41c57db'
-end
+gem 'simplecov', git: 'https://github.com/DataDog/simplecov', ref: '3bb6b7ee58bf4b1954ca205f50dd44d6f41c57db'
 
 gem 'simplecov-cobertura', '~> 2.1.0' # Used by codecov
 
@@ -104,5 +100,5 @@ gem 'ffi', '~> 1.16.3', require: false
 
 # Ruby 3.4 should be supported by strscan v3.1.1. However, the latest release of strscan is v3.1.0.
 #
-# TODO: Remove this v3.1.0 requirement once v3.1.1 is released.
-gem 'strscan', '3.1.0' if RUBY_VERSION.start_with?('3.4.')
+# TODO: Remove this once v3.1.1 is released.
+gem 'strscan', git: 'https://github.com/ruby/strscan' if RUBY_VERSION.start_with?('3.4.')

spec/datadog/core/environment/execution_spec.rb

@@ -191,7 +191,8 @@ def test_it_does_something_useful
                 Open3.capture3('ruby', stdin_data: script)
               end
 
-              skip('DEBUG')
+              # Ruby 3.4 outputs an exception instead of the information to be asserted because of the forked process.
+              pending('Pending for Ruby 3.4.') if RUBY_VERSION.start_with?('3.4.')
               expect(err).to include('ACTUAL:true')
             end
           end

spec/datadog/core/error_spec.rb

@@ -89,6 +89,8 @@ def call
           expect(error.message).to eq('wrapper layer')
 
           # Outer-most error first, inner-most last
+          # Ruby 3.4 adjusts the format of error messages and Hash#inspect renderings
+          # https://www.ruby-lang.org/en/news/2024/10/07/ruby-3-4-0-preview2-released/
           wrapper_error_message = /in.*wrapper': wrapper layer \(RuntimeError\)/
           wrapper_caller = /from.*in ['`]call'/
           middle_error_message = /in.*middle': middle cause \(RuntimeError\)/