Test on Ruby 3.1

.github/workflows/tests.yml

@@ -294,6 +294,12 @@ jobs:
           - name: tests (macOS 13)
             test-flags: --coverage
             runs-on: macos-13
+          - name: tests (Ubuntu 22.04; Ruby 3.1)
+            runs-on: ubuntu-22.04
+            ruby: '3.1'
+          - name: tests (macOS 13; Ruby 3.1)
+            runs-on: macos-13
+            ruby: '3.1'
     steps:
       - name: Set up Homebrew
         id: set-up-homebrew
@@ -307,8 +313,23 @@ jobs:
         uses: actions/cache@v3
         with:
           path: ${{ steps.set-up-homebrew.outputs.gems-path }}
-          key: ${{ runner.os }}-rubygems-${{ steps.set-up-homebrew.outputs.gems-hash }}
-          restore-keys: ${{ runner.os }}-rubygems-
+          key: ${{ runner.os }}-rubygems${{ matrix.ruby }}-${{ steps.set-up-homebrew.outputs.gems-hash }}
+          restore-keys: ${{ runner.os }}-rubygems${{ matrix.ruby }}-
+
+      - name: Setup Ruby
+        if: matrix.ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+
+      - name: Setup Ruby environment
+        if: matrix.ruby
+        run: |
+          echo "HOMEBREW_USE_RUBY_FROM_PATH=1" >> "${GITHUB_ENV}"
+          echo "HOMEBREW_BOOTSNAP=" >> "${GITHUB_ENV}" # Unsupported, for now
+          rm -rf "${{ steps.set-up-homebrew.outputs.repository-path }}/Library/Homebrew/vendor/portable-ruby"
+
+      - run: brew config
 
       - name: Install Bundler RubyGems
         run: brew install-bundler-gems --groups=all
@@ -320,8 +341,8 @@ jobs:
         uses: actions/cache@v3
         with:
           path: tests
-          key: ${{ runner.os }}-${{ matrix.test-flags }}-parallel_runtime_rspec-${{ github.sha }}
-          restore-keys: ${{ runner.os }}-${{ matrix.test-flags }}-parallel_runtime_rspec-
+          key: ${{ runner.os }}-${{ matrix.test-flags }}-parallel_runtime_rspec${{ matrix.ruby }}-${{ github.sha }}
+          restore-keys: ${{ runner.os }}-${{ matrix.test-flags }}-parallel_runtime_rspec${{ matrix.ruby }}-
 
       - name: Install brew tests dependencies
         if: matrix.name != 'tests (generic OS)'

.gitignore

@@ -37,6 +37,10 @@
 **/vendor/bundle/ruby/*/plugins
 **/vendor/bundle/ruby/*/specifications
 
+# Ignore Ruby gems for versions other than we explicitly vendor
+**/vendor/bundle/ruby/*/
+!**/vendor/bundle/ruby/2.6.0/
+
 # Ignore Bundler binary files
 **/vendor/bundle/ruby/*/gems/**/*.bundle
 

Library/Homebrew/Gemfile

@@ -4,7 +4,7 @@ source "https://rubygems.org"
 
 # The default case (no envs), should always be a restrictive bound on the lowest supported minor version.
 # This is the branch that Dependabot will use.
-if ENV.fetch("HOMEBREW_DEVELOPER", "").empty? || ENV.fetch("HOMEBREW_USE_RUBY_FROM_PATH", "").empty?
+if ENV.fetch("HOMEBREW_USE_RUBY_FROM_PATH", "").empty?
   ruby "~> 2.6.0"
 else
   ruby ">= 2.6.0"

Library/Homebrew/dev-cmd/tests.rb

@@ -208,8 +208,8 @@ module Homebrew
       HOMEBREW_CACHE
       HOMEBREW_LOGS
       HOMEBREW_TEMP
-      HOMEBREW_USE_RUBY_FROM_PATH
     ]
+    allowed_test_env << "HOMEBREW_USE_RUBY_FROM_PATH" if Homebrew::EnvConfig.developer?
     Homebrew::EnvConfig::ENVS.keys.map(&:to_s).each do |env|
       next if allowed_test_env.include?(env)
 

Library/Homebrew/test/rubocop_spec.rb

@@ -6,7 +6,11 @@ describe "RuboCop" do
   context "when calling `rubocop` outside of the Homebrew environment" do
     before do
       ENV.each_key do |key|
-        ENV.delete(key) if key.start_with?("HOMEBREW_") && key != "HOMEBREW_USE_RUBY_FROM_PATH"
+        allowlist = %w[
+          HOMEBREW_TESTS
+          HOMEBREW_USE_RUBY_FROM_PATH
+        ]
+        ENV.delete(key) if key.start_with?("HOMEBREW_") && allowlist.exclude?(key)
       end
 
       ENV["XDG_CACHE_HOME"] = (HOMEBREW_CACHE.realpath/"style").to_s

Library/Homebrew/test/utils/ruby_check_version_script_spec.rb

@@ -5,6 +5,7 @@ describe Utils do
     subject do
       homebrew_env = ENV.select { |key, _| key.start_with?("HOMEBREW_") }
       Bundler.with_unbundled_env do
+        ENV.delete_if { |key,| key.start_with?("HOMEBREW_") }
         ENV.update(homebrew_env)
         quiet_system "#{HOMEBREW_LIBRARY_PATH}/utils/ruby_check_version_script.rb", required_ruby_version
       end

Library/Homebrew/utils/gems.rb

@@ -177,13 +177,16 @@ module Homebrew
   def user_gem_groups
     @user_gem_groups ||= if GEM_GROUPS_FILE.exist?
       GEM_GROUPS_FILE.readlines(chomp: true)
-    else
-      # Backwards compatibility. This else block can be replaced by `[]` by the end of 2023.
+    elsif RUBY_VERSION < "2.7"
+      # Backwards compatibility. This elsif block removed by the end of 2023.
+      # We will not support this in Ruby >=2.7.
       require "settings"
       groups = Homebrew::Settings.read(:gemgroups)&.split(";") || []
       write_user_gem_groups(groups)
       Homebrew::Settings.delete(:gemgroups)
       groups
+    else
+      []
     end
   end
 
@@ -194,8 +197,9 @@ module Homebrew
   def forget_user_gem_groups!
     if GEM_GROUPS_FILE.exist?
       GEM_GROUPS_FILE.truncate(0)
-    else
+    elsif RUBY_VERSION < "2.7"
       # Backwards compatibility. This else block can be removed by the end of 2023.
+      # We will not support this in Ruby >=2.7.
       require "settings"
       Homebrew::Settings.delete(:gemgroups)
     end

Library/Homebrew/utils/ruby.sh

@@ -16,7 +16,7 @@ test_ruby() {
 }
 
 can_use_ruby_from_path() {
-  if [[ -n "${HOMEBREW_DEVELOPER}" && -n "${HOMEBREW_USE_RUBY_FROM_PATH}" ]]
+  if [[ -n "${HOMEBREW_DEVELOPER}" || -n "${HOMEBREW_TESTS}" ]] && [[ -n "${HOMEBREW_USE_RUBY_FROM_PATH}" ]]
   then
     return 0
   fi

Library/Homebrew/utils/ruby_check_version_script.rb

@@ -17,7 +17,7 @@ ruby_version_major, ruby_version_minor, = ruby_version.canonical_segments
 homebrew_required_ruby_version_major, homebrew_required_ruby_version_minor, =
   homebrew_required_ruby_version.canonical_segments
 
-if !ENV.fetch("HOMEBREW_DEVELOPER", "").empty? &&
+if (!ENV.fetch("HOMEBREW_DEVELOPER", "").empty? || !ENV.fetch("HOMEBREW_TESTS", "").empty?) &&
    !ENV.fetch("HOMEBREW_USE_RUBY_FROM_PATH", "").empty? &&
    ruby_version >= homebrew_required_ruby_version
   return