Add Rubocop Cop that ensures bare constants are not used28109-unqualified-constants-cop

3 files changed, 191 insertions, 0 deletions

diff --git a/rubocop/cop/unqualified_constants.rb b/rubocop/cop/unqualified_constants.rb
new file mode 100644
index 00000000000..54d1baa878c
--- /dev/null
+++ b/rubocop/cop/unqualified_constants.rb
@@ -0,0 +1,31 @@
+require_relative '../spec_helpers'
+
+module RuboCop
+  module Cop
+    # Cop that makes sure workers include `ApplicationWorker`, not `Sidekiq::Worker`.
+    class FullyQualifiedConstants < RuboCop::Cop::Cop
+      include RuboCop::SpecHelpers
+
+      MSG = 'Do not use unqualified constants (ex. Use `Gitlab::Util` instead of `Util`).'.freeze
+
+      def_node_matcher :extend_include_prepend_bare?, <<~PATTERN
+        (send nil? {:extend :include :prepend} #bare_constant?)
+      PATTERN
+
+      def_node_matcher :send_to_bare_constant?, <<~PATTERN
+        (send #bare_constant? ...)
+      PATTERN
+
+      def_node_matcher :bare_constant?, <<~PATTERN
+        (const nil? _)
+      PATTERN
+
+      def on_send(node)
+        return if in_spec?(node)
+
+        add_offense(node.arguments.first, location: :expression) if extend_include_prepend_bare?(node)
+        add_offense(node, location: :expression) if send_to_bare_constant?(node)
+      end
+    end
+  end
+end
diff --git a/rubocop/rubocop.rb b/rubocop/rubocop.rb
index f05990232ab..00b7690ba69 100644
--- a/rubocop/rubocop.rb
+++ b/rubocop/rubocop.rb
@@ -25,3 +25,4 @@ require_relative 'cop/project_path_helper'
 require_relative 'cop/rspec/env_assignment'
 require_relative 'cop/rspec/factories_in_migration_specs'
 require_relative 'cop/sidekiq_options_queue'
+require_relative 'cop/unqualified_constants'
diff --git a/spec/rubocop/cop/unqualified_constants_spec.rb b/spec/rubocop/cop/unqualified_constants_spec.rb
new file mode 100644
index 00000000000..c4e37142930
--- /dev/null
+++ b/spec/rubocop/cop/unqualified_constants_spec.rb
@@ -0,0 +1,159 @@
+
+require 'spec_helper'
+require 'rubocop'
+require 'rubocop/rspec/support'
+require_relative '../../../rubocop/cop/unqualified_constants'
+
+describe RuboCop::Cop::FullyQualifiedConstants do
+  include CopHelper
+
+  subject(:cop) { described_class.new }
+  
+  shared_examples('registering offense') do |options|
+    let(:offending_lines) { options[:offending_lines] }
+
+    it 'registers an offense when not using a fully-qualified constant' do
+      inspect_source(source)
+
+      aggregate_failures do
+        expect(cop.offenses.size).to eq(offending_lines.size)
+        expect(cop.offenses.map(&:line)).to eq(offending_lines)
+      end
+    end
+  end
+
+  shared_examples('not registering offense') do
+    it 'does not register offenses' do
+      inspect_source(source)
+
+      expect(cop.offenses).to be_empty
+    end
+  end
+
+  context 'when extending' do
+    context 'with unqualified constant' do
+      it_behaves_like 'registering offense', offending_lines: [2] do
+        let(:source) do
+          <<~RUBY
+            class C
+              extend Test
+              def really?
+                @really ||= true
+              end
+            end
+          RUBY
+        end
+      end
+    end
+
+    context 'with qualified constant' do
+      it_behaves_like 'not registering offense' do
+        let(:source) do
+          <<~RUBY
+            class C
+              extend Gitlab::Test
+              def really?
+                @really ||= ::User.find(some_var)
+              end
+            end
+          RUBY
+        end
+      end
+    end
+  end
+
+  context 'when including' do
+    context 'with unqualified constant' do
+      it_behaves_like 'registering offense', offending_lines: [2] do
+        let(:source) do
+          <<~RUBY
+            class C
+              include Test
+              def really?
+                @really ||= true
+              end
+            end
+          RUBY
+        end
+      end
+    end
+
+    context 'with qualified constant' do
+      it_behaves_like 'not registering offense' do
+        let(:source) do
+          <<~RUBY
+            class C
+              include Gitlab::Test
+              def really?
+                @really ||= true
+              end
+            end
+          RUBY
+        end
+      end
+    end
+  end
+
+  context 'when prepending' do
+    context 'with unqualified constant' do
+      it_behaves_like 'registering offense', offending_lines: [2] do
+        let(:source) do
+          <<~RUBY
+            class C
+              prepend Test
+              def really?
+                @really ||= true
+              end
+            end
+          RUBY
+        end
+      end
+    end
+
+    context 'with qualified constant' do
+      it_behaves_like 'not registering offense' do
+        let(:source) do
+          <<~RUBY
+            class C
+              prepend Another::Test
+              def really?
+                @really ||= true
+              end
+            end
+          RUBY
+        end
+      end
+    end
+  end
+
+  context 'when sending' do
+    context 'with qualified constant' do
+      it_behaves_like 'registering offense', offending_lines: [3, 4] do
+        let(:source) do
+          <<~RUBY
+            class C
+              def really?
+                @really ||= User.find(1)
+                @other = User.find(2)
+              end
+            end
+          RUBY
+        end
+      end
+    end
+
+    context 'with unqualified constant' do
+      it_behaves_like 'not registering offense' do
+        let(:source) do
+          <<~RUBY
+            class C
+              def really?
+                @really ||= ::User.find(1)
+              end
+            end
+          RUBY
+        end
+      end
+    end
+  end
+end