[Fix #11920] Skip files that don't satisfy gem version reqs

changelog/new_requires_gem_api.md

@@ -0,0 +1 @@
+* [#12186](https://github.com/rubocop/rubocop/pull/12186): Add new `requires_gem` API for declaring which gems a Cop needs. ([@amomchilov][])

lib/rubocop/cop/base.rb

@@ -269,6 +269,7 @@ def active_support_extensions_enabled?
       end
 
       def relevant_file?(file)
+        return false unless target_satisfies_all_gem_version_requirements?
         return true unless @config.clusivity_config_for_badge?(self.class.badge)
 
         file == RuboCop::AST::ProcessedSource::STRING_SOURCE_NAME ||

lib/rubocop/cop/team.rb

@@ -174,6 +174,9 @@ def support_target_ruby_version?(cop)
       end
 
       def support_target_rails_version?(cop)
+        # In this case, the rails version was already checked by `#excluded_file?`
+        return true if defined?(RuboCop::Rails::TargetRailsVersion::USES_REQUIRES_GEM_API)
+
         return true unless cop.class.respond_to?(:support_target_rails_version?)
 
         cop.class.support_target_rails_version?(cop.target_rails_version)

lib/rubocop/rspec/shared_contexts.rb

@@ -110,7 +110,19 @@ def source_range(range, buffer: source_buffer)
   let(:config) do
     hash = { 'AllCops' => all_cops_config, cop_class.cop_name => cur_cop_config }.merge!(other_cops)
 
-    RuboCop::Config.new(hash, "#{Dir.pwd}/.rubocop.yml")
+    config = RuboCop::Config.new(hash, "#{Dir.pwd}/.rubocop.yml")
+
+    rails_version_in_gemfile = Gem::Version.new(
+      rails_version || RuboCop::Config::DEFAULT_RAILS_VERSION
+    )
+
+    allow(config).to receive(:gem_versions_in_target).and_return(
+      {
+        'railties' => rails_version_in_gemfile
+      }
+    )
+
+    config
   end
 
   let(:cop) { cop_class.new(config, cop_options) }

spec/rubocop/cop/cop_spec.rb

@@ -378,6 +378,71 @@ def autocorrect(node); end
 
       it { is_expected.to be(true) }
     end
+
+    describe 'for a cop with gem version requirements', :restore_registry do
+      subject { cop.relevant_file?(file) }
+
+      let(:file) { 'foo.rb' }
+
+      let(:cop_class) do
+        stub_cop_class('CopSpec::CopWithGemReqs') do
+          requires_gem 'gem1', '>= 1.2.3'
+        end
+      end
+
+      before do
+        allow(config).to receive(:gem_versions_in_target).and_return(gem_versions_in_target)
+      end
+
+      context 'the target doesn\'t satisfy any of the gem requirements' do
+        let(:gem_versions_in_target) { {} }
+
+        it { is_expected.to be(false) }
+      end
+
+      context 'the target has a required gem, but in a version that\'s too old' do
+        let(:gem_versions_in_target) { { 'gem1' => Gem::Version.new('1.2.2') } }
+
+        it { is_expected.to be(false) }
+      end
+
+      context 'the target has a required gem, in a supported version' do
+        let(:gem_versions_in_target) { { 'gem1' => Gem::Version.new('1.2.3') } }
+
+        it { is_expected.to be(true) }
+      end
+
+      context 'for a cop with multiple gem requirements' do
+        let(:cop_class) do
+          stub_cop_class('CopSpec::CopWithGemReqs') do
+            requires_gem 'gem1', '>= 1.2.3'
+            requires_gem 'gem2', '>= 4.5.6'
+          end
+        end
+
+        context 'the target satisfies one but not all of the gem requirements' do
+          let(:gem_versions_in_target) do
+            {
+              'gem1' => Gem::Version.new('1.2.3'),
+              'gem2' => Gem::Version.new('4.5.5')
+            }
+          end
+
+          it { is_expected.to be(false) }
+        end
+
+        context 'the target has all the required gems with sufficient versions' do
+          let(:gem_versions_in_target) do
+            {
+              'gem1' => Gem::Version.new('1.2.3'),
+              'gem2' => Gem::Version.new('4.5.6')
+            }
+          end
+
+          it { is_expected.to be(true) }
+        end
+      end
+    end
   end
 
   describe '#safe_autocorrect?' do