[Fix #7745] Suppress pending cop warnings when department is disabled

Fixes #7745.

This PR suppresses a pending cop warnings when pending cop's
department is disabled.

## Context

```console
% rubocop -V
0.80.0 (using Parser 2.7.0.2, running on ruby 2.7.0 x86_64-darwin17)
```

```yaml
% cat .rubocop.yml
Style:
  Enabled: false
```

## Before

The following pending cop warning is displayed for disabled Style department.

```console
% bundle exec rubocop
The following cops were added to RuboCop, but are not configured. Please
set Enabled to either `true` or `false` in your `.rubocop.yml` file:
 - Style/HashEachMethods
 - Style/HashTransformKeys
 - Style/HashTransformValues
Inspecting 0 files

0 files inspected, no offenses detected
```

## After

A pending cop warning is not displayed for disabled Style department.

```console
% bundle exec rubocop
Inspecting 0 files

0 files inspected, no offenses detected
```

CHANGELOG.md

@@ -7,6 +7,7 @@
 * [#7719](https://github.com/rubocop-hq/rubocop/issues/7719): Fix `Style/NestedParenthesizedCalls` cop for newline. ([@tejasbubane][])
 * [#7709](https://github.com/rubocop-hq/rubocop/issues/7709): Fix correction of `Style/RedundantCondition` when the else branch contains a range. ([@rrosenblum][])
 * [#7682](https://github.com/rubocop-hq/rubocop/issues/7682): Fix `Style/InverseMethods` autofix leaving parenthesis. ([@tejasbubane][])
+* [#7745](https://github.com/rubocop-hq/rubocop/issues/7745): Suppress a pending cop warnings when pending cop's department is disabled. ([@koic][])
 
 ## 0.80.0 (2020-02-18)
 

lib/rubocop/config.rb

@@ -2,6 +2,9 @@
 
 require 'pathname'
 
+# FIXME: Moving Rails department code to RuboCop Rails will remove
+# the following rubocop:disable comment.
+# rubocop:disable Metrics/ClassLength
 module RuboCop
   # This class represents the configuration of the RuboCop application
   # and all its cops. A Config is associated with a YAML configuration
@@ -215,6 +218,15 @@ def bundler_lock_file_path
       nil
     end
 
+    def pending_cops
+      keys.select do |qualified_cop_name|
+        department = department_of(qualified_cop_name)
+        next if department && department['Enabled'] == false
+
+        self[qualified_cop_name]['Enabled'] == 'pending'
+      end
+    end
+
     private
 
     def target_rails_version_from_bundler_lock_file
@@ -235,17 +247,18 @@ def read_rails_version_from_bundler_lock_file
     end
 
     def enable_cop?(qualified_cop_name, cop_options)
-      cop_department, cop_name = qualified_cop_name.split('/')
-      department = cop_name.nil?
-
-      unless department
-        department_options = self[cop_department]
-        if department_options && department_options['Enabled'] == false
-          return false
-        end
-      end
+      department = department_of(qualified_cop_name)
+      return false if department && department['Enabled'] == false
 
       cop_options.fetch('Enabled') { !for_all_cops['DisabledByDefault'] }
     end
+
+    def department_of(qualified_cop_name)
+      cop_department, cop_name = qualified_cop_name.split('/')
+      return nil if cop_name.nil?
+
+      self[cop_department]
+    end
   end
 end
+# rubocop:enable Metrics/ClassLength

lib/rubocop/config_loader.rb

@@ -117,11 +117,8 @@ def default_configuration
       end
 
       def warn_on_pending_cops(config)
-        pending_cops = config.keys.select do |key|
-          config[key]['Enabled'] == 'pending'
-        end
-
-        return if pending_cops.none?
+        pending_cops = config.pending_cops
+        return if pending_cops.empty?
 
         warn Rainbow('The following cops were added to RuboCop, but are not ' \
                      'configured. Please set Enabled to either `true` or ' \

spec/rubocop/cli/cli_options_spec.rb

@@ -220,47 +220,81 @@ class SomeCop < Cop
           RESULT
       end
 
-      it 'accepts cop names from plugins with a pending cop' do
-        create_file('.rubocop.yml', <<~YAML)
-          require: rubocop_ext
+      context 'when specifying a pending cop' do
+        let(:rubocop) { "#{RuboCop::ConfigLoader::RUBOCOP_HOME}/exe/rubocop" }
 
-          Style/SomeCop:
-            Description: Something
-            Enabled: pending
-        YAML
-        create_file('rubocop_ext.rb', <<~RUBY)
-          module RuboCop
-            module Cop
-              module Style
-                class SomeCop < Cop
-                end
-              end
-            end
-          end
-        RUBY
-        create_file('redirect.rb', '$stderr = STDOUT')
-        rubocop = "#{RuboCop::ConfigLoader::RUBOCOP_HOME}/exe/rubocop"
         # Since we define a new cop class, we have to do this in a separate
         # process. Otherwise, the extra cop will affect other specs.
-        output =
+        let(:output) do
           `ruby -I . "#{rubocop}" --require redirect.rb --only Style/SomeCop`
+        end
 
-        expected_prefix = <<~PREFIX
+        let(:pending_cop_warning) { <<~PENDING_COP_WARNING }
           The following cops were added to RuboCop, but are not configured. Please set Enabled to either `true` or `false` in your `.rubocop.yml` file:
-        PREFIX
-        expected_suffix = <<~SUFFIX
+        PENDING_COP_WARNING
+
+        let(:inspected_output) { <<~INSPECTED_OUTPUT }
           Inspecting 2 files
           ..
 
           2 files inspected, no offenses detected
-        SUFFIX
+        INSPECTED_OUTPUT
 
-        expect(output).to start_with(expected_prefix)
-        expect(output).to end_with(expected_suffix)
+        before do
+          create_file('rubocop_ext.rb', <<~RUBY)
+            module RuboCop
+              module Cop
+                module Style
+                  class SomeCop < Cop
+                  end
+                end
+              end
+            end
+          RUBY
+
+          create_file('redirect.rb', '$stderr = STDOUT')
+        end
+
+        context 'when Style department is enabled' do
+          before do
+            create_file('.rubocop.yml', <<~YAML)
+              require: rubocop_ext
+
+              Style/SomeCop:
+                Description: Something
+                Enabled: pending
+            YAML
+          end
 
-        remaining_range = expected_prefix.length..-(expected_suffix.length + 1)
-        pending_cops = output[remaining_range].split("\n")
-        expect(pending_cops).to include(' - Style/SomeCop')
+          it 'accepts cop names from plugins with a pending cop warning' do
+            expect(output).to start_with(pending_cop_warning)
+            expect(output).to end_with(inspected_output)
+
+            remaining_range =
+              pending_cop_warning.length..-(inspected_output.length + 1)
+            pending_cops = output[remaining_range].split("\n")
+            expect(pending_cops).to include(' - Style/SomeCop')
+          end
+        end
+
+        context 'when Style department is disabled' do
+          before do
+            create_file('.rubocop.yml', <<~YAML)
+              require: rubocop_ext
+
+              Style:
+                Enabled: false
+
+              Style/SomeCop:
+                Description: Something
+                Enabled: pending
+            YAML
+          end
+
+          it 'does not show pending cop warning' do
+            expect(output).to eq(inspected_output)
+          end
+        end
       end
 
       context 'without using namespace' do