[Fix #10263] Fix aliasing problem for Enabled in Config

There was an aliasing problem in the `Config` class causing the
`cop_options` local variable to reference the same object between
different calls to `for_cop` even when the calls were to different
`Config` objects with different `@hash` objects.

I have not been able to figure out the root cause. Only that the
phenomenon occurs, and that duplicating the cop options before
setting the `Enabled` property resolves it.

changelog/fix_disabling_leaking_between_directories.md

@@ -0,0 +1 @@
+* [#10263](https://github.com/rubocop/rubocop/pull/10263): Fix the value of `Enabled` leaking between configurations. ([@jonas054][])

lib/rubocop/config.rb

@@ -25,7 +25,7 @@ def initialize(hash = {}, loaded_path = nil)
       @loaded_path = loaded_path
       @for_cop = Hash.new do |h, cop|
         qualified_cop_name = Cop::Registry.qualified_cop_name(cop, loaded_path)
-        cop_options = self[qualified_cop_name] || {}
+        cop_options = self[qualified_cop_name].dup || {}
         cop_options['Enabled'] = enable_cop?(qualified_cop_name, cop_options)
         h[cop] = cop_options
       end

spec/rubocop/config_loader_spec.rb

@@ -635,6 +635,42 @@
       end
     end
 
+    context 'when a department is enabled in the top directory and disabled in a subdirectory' do
+      let(:file_path) { '.rubocop.yml' }
+      let(:configuration_from_subdir) do
+        described_class.configuration_from_file('subdir/.rubocop.yml')
+      end
+
+      before do
+        stub_const('RuboCop::ConfigLoader::RUBOCOP_HOME', 'rubocop')
+        stub_const('RuboCop::ConfigLoader::DEFAULT_FILE',
+                   File.join('rubocop', 'config', 'default.yml'))
+
+        create_file('rubocop/config/default.yml', <<~YAML)
+          Layout/SomeCop:
+            Enabled: pending
+        YAML
+        create_file(file_path, <<~YAML)
+          Layout:
+            Enabled: true
+        YAML
+        create_file('subdir/.rubocop.yml', <<~YAML)
+          Layout:
+            Enabled: false
+        YAML
+      end
+
+      it 'does not disable pending cops of that department in the top directory' do
+        # The cop is disabled in subdir because its department is disabled there.
+        subdir_configuration = configuration_from_subdir.for_cop('Layout/SomeCop')
+        expect(subdir_configuration['Enabled']).to be(false)
+
+        # The disabling of the cop in subdir should not leak into the top directory.
+        examples_configuration = configuration_from_file.for_cop('Layout/SomeCop')
+        expect(examples_configuration['Enabled']).to eq('pending')
+      end
+    end
+
     context 'when a department is disabled', :restore_registry do
       let(:file_path) { '.rubocop.yml' }