Merge branch 'rubocop-prepend' into 'master'

Added Cop for injecting EE modules

See merge request gitlab-org/gitlab-ce!23802

.rubocop.yml

@@ -174,3 +174,9 @@ GitlabSecurity/PublicSend:
     - 'ee/db/**/*'
     - 'ee/lib/**/*.rake'
     - 'ee/spec/**/*'
+
+Cop/InjectEnterpriseEditionModule:
+  Enabled: true
+  Exclude:
+    - 'spec/**/*'
+    - 'ee/spec/**/*'

rubocop/cop/inject_enterprise_edition_module.rb

+# frozen_string_literal: true
+
+module RuboCop
+  module Cop
+    # Cop that blacklists the injecting of EE specific modules anywhere but on
+    # the last line of a file. Injecting a module in the middle of a file will
+    # cause merge conflicts, while placing it on the last line will not.
+    class InjectEnterpriseEditionModule < RuboCop::Cop::Cop
+      MSG = 'Injecting EE modules must be done on the last line of this file' \
+        ', outside of any class or module definitions'
+
+      METHODS = Set.new(%i[include extend prepend]).freeze
+
+      def_node_matcher :ee_const?, <<~PATTERN
+        (const (const _ :EE) _)
+      PATTERN
+
+      def on_send(node)
+        return unless METHODS.include?(node.children[1])
+        return unless ee_const?(node.children[2])
+
+        line = node.location.line
+        buffer = node.location.expression.source_buffer
+        last_line = buffer.last_line
+
+        # Parser treats the final newline (if present) as a separate line,
+        # meaning that a simple `line < last_line` would yield true even though
+        # the expression is the last line _of code_.
+        last_line -= 1 if buffer.source.end_with?("\n")
+
+        add_offense(node) if line < last_line
+      end
+
+      # Automatically correcting these offenses is not always possible, as
+      # sometimes code needs to be refactored to make this work. As such, we
+      # only allow developers to easily blacklist existing offenses.
+      def autocorrect(node)
+        lambda do |corrector|
+          corrector.insert_after(
+            node.source_range,
+            " # rubocop: disable #{cop_name}"
+          )
+        end
+      end
+    end
+  end
+end

rubocop/rubocop.rb

@@ -41,3 +41,4 @@ require_relative 'cop/code_reuse/presenter'
 require_relative 'cop/code_reuse/serializer'
 require_relative 'cop/code_reuse/active_record'
 require_relative 'cop/group_public_or_visible_to_user'
+require_relative 'cop/inject_enterprise_edition_module'

spec/rubocop/cop/inject_enterprise_edition_module_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+require 'rubocop'
+require 'rubocop/rspec/support'
+require_relative '../../../rubocop/cop/inject_enterprise_edition_module'
+
+describe RuboCop::Cop::InjectEnterpriseEditionModule do
+  include CopHelper
+
+  subject(:cop) { described_class.new }
+
+  it 'flags the use of `prepend EE` in the middle of a file' do
+    expect_offense(<<~SOURCE)
+    class Foo
+      prepend EE::Foo
+      ^^^^^^^^^^^^^^^ Injecting EE modules must be done on the last line of this file, outside of any class or module definitions
+    end
+    SOURCE
+  end
+
+  it 'flags the use of `prepend ::EE` in the middle of a file' do
+    expect_offense(<<~SOURCE)
+    class Foo
+      prepend ::EE::Foo
+      ^^^^^^^^^^^^^^^^^ Injecting EE modules must be done on the last line of this file, outside of any class or module definitions
+    end
+    SOURCE
+  end
+
+  it 'flags the use of `include EE` in the middle of a file' do
+    expect_offense(<<~SOURCE)
+    class Foo
+      include EE::Foo
+      ^^^^^^^^^^^^^^^ Injecting EE modules must be done on the last line of this file, outside of any class or module definitions
+    end
+    SOURCE
+  end
+
+  it 'flags the use of `include ::EE` in the middle of a file' do
+    expect_offense(<<~SOURCE)
+    class Foo
+      include ::EE::Foo
+      ^^^^^^^^^^^^^^^^^ Injecting EE modules must be done on the last line of this file, outside of any class or module definitions
+    end
+    SOURCE
+  end
+
+  it 'flags the use of `extend EE` in the middle of a file' do
+    expect_offense(<<~SOURCE)
+    class Foo
+      extend EE::Foo
+      ^^^^^^^^^^^^^^ Injecting EE modules must be done on the last line of this file, outside of any class or module definitions
+    end
+    SOURCE
+  end
+
+  it 'flags the use of `extend ::EE` in the middle of a file' do
+    expect_offense(<<~SOURCE)
+    class Foo
+      extend ::EE::Foo
+      ^^^^^^^^^^^^^^^^ Injecting EE modules must be done on the last line of this file, outside of any class or module definitions
+    end
+    SOURCE
+  end
+
+  it 'does not flag prepending of regular modules' do
+    expect_no_offenses(<<~SOURCE)
+    class Foo
+      prepend Foo
+    end
+    SOURCE
+  end
+
+  it 'does not flag including of regular modules' do
+    expect_no_offenses(<<~SOURCE)
+    class Foo
+      include Foo
+    end
+    SOURCE
+  end
+
+  it 'does not flag extending using regular modules' do
+    expect_no_offenses(<<~SOURCE)
+    class Foo
+      extend Foo
+    end
+    SOURCE
+  end
+
+  it 'does not flag the use of `prepend EE` on the last line' do
+    expect_no_offenses(<<~SOURCE)
+    class Foo
+    end
+
+    Foo.prepend(EE::Foo)
+    SOURCE
+  end
+
+  it 'does not flag the use of `include EE` on the last line' do
+    expect_no_offenses(<<~SOURCE)
+    class Foo
+    end
+
+    Foo.include(EE::Foo)
+    SOURCE
+  end
+
+  it 'does not flag the use of `extend EE` on the last line' do
+    expect_no_offenses(<<~SOURCE)
+    class Foo
+    end
+
+    Foo.extend(EE::Foo)
+    SOURCE
+  end
+
+  it 'autocorrects offenses by just disabling the Cop' do
+    source = <<~SOURCE
+    class Foo
+      prepend EE::Foo
+      include Bar
+    end
+    SOURCE
+
+    expect(autocorrect_source(source)).to eq(<<~SOURCE)
+    class Foo
+      prepend EE::Foo # rubocop: disable Cop/InjectEnterpriseEditionModule
+      include Bar
+    end
+    SOURCE
+  end
+end