Merge pull request #4 from utkarsh2102/add-relative_require_to_lib-cop

Implement the new RelativeRequireToLib cop + add tests

.rubocop.yml

@@ -12,6 +12,10 @@ AllCops:
     - 'vendor/**/*'
   TargetRubyVersion: 2.4
 
+Packaging/RelativeRequireToLib:
+  Include:
+    - spec/**/*.rb
+
 Naming/FileName:
   Exclude:
     - lib/rubocop-packaging.rb
@@ -28,6 +32,3 @@ Metrics/BlockLength:
 Metrics/MethodLength:
   Exclude:
     - tasks/*.rake
-
-Layout/LineLength:
-  Max: 120

.travis.yml

@@ -3,7 +3,6 @@ language: ruby
 cache: bundler
 before_install: gem install bundler -v 2.1.4
 rvm:
-  - 2.4.10
   - 2.5.8
   - 2.6.6
   - 2.7.1

Rakefile

@@ -15,7 +15,6 @@ RuboCop::RakeTask.new
 task default: %i[
   spec
   rubocop
-  generate_cops_documentation
 ]
 
 desc 'Generate a new cop with a template'

config/default.yml

@@ -3,4 +3,10 @@
 Packaging/GemspecGit:
   Description: 'Use pure Ruby alternative instead of `git ls-files`.'
   Enabled: true
-  VersionAdded: '0.86'
+  VersionAdded: '0.1'
+  VersionChanged: '0.1'
+
+Packaging/RelativeRequireToLib:
+  Description: 'Avoid using `require_relative` with relative path to lib.'
+  Enabled: true
+  VersionAdded: '0.2'

docs/modules/ROOT/pages/cops.adoc

@@ -3,5 +3,6 @@
 = Department xref:cops_packaging.adoc[Packaging]
 
 * xref:cops_packaging.adoc#packaginggemspecgit[Packaging/GemspecGit]
+* xref:cops_packaging.adoc#packagingrelativerequiretolib[Packaging/RelativeRequireToLib]
 
 // END_COP_LIST

docs/modules/ROOT/pages/cops_packaging.adoc

@@ -8,8 +8,8 @@
 | Enabled
 | Yes
 | No
-| 0.86
-| -
+| 0.1
+| 0.1
 |===
 
 This cop is used to identify the usage of `git ls-files`
@@ -57,3 +57,40 @@ Gem::Specification.new do |spec|
   spec.executables   = Dir.glob('bin/*').map{ |f| File.basename(f) }
 end
 ----
+
+== Packaging/RelativeRequireToLib
+
+|===
+| Enabled by default | Safe | Supports autocorrection | VersionAdded | VersionChanged
+
+| Enabled
+| Yes
+| No
+| 0.2
+| -
+|===
+
+This cop is used to identify the `require_relative` calls,
+mapping to the "lib" directory and suggests to use `require`
+instead.
+
+=== Examples
+
+[source,ruby]
+----
+# bad
+require_relative 'lib/foo.rb'
+
+# bad
+require_relative '../../lib/foo/bar'
+
+# good
+require 'foo.rb'
+
+# good
+require 'foo/bar'
+
+# good
+require_relative 'spec_helper'
+require_relative 'foo/bar'
+----

lib/rubocop/cop/packaging/relative_require_to_lib.rb

@@ -0,0 +1,67 @@
+# frozen_string_literal: true
+
+module RuboCop # :nodoc:
+  module Cop # :nodoc:
+    module Packaging # :nodoc:
+      # This cop is used to identify the `require_relative` calls,
+      # mapping to the "lib" directory and suggests to use `require`
+      # instead.
+      #
+      # @example
+      #
+      #   # bad
+      #   require_relative 'lib/foo.rb'
+      #
+      #   # bad
+      #   require_relative '../../lib/foo/bar'
+      #
+      #   # good
+      #   require 'foo.rb'
+      #
+      #   # good
+      #   require 'foo/bar'
+      #
+      #   # good
+      #   require_relative 'spec_helper'
+      #   require_relative 'foo/bar'
+      #
+      class RelativeRequireToLib < Base
+        # This is the message that will be displayed when RuboCop finds an
+        # offense of using `require_relative` with relative path to lib.
+        MSG = 'Avoid using `require_relative` with relative path to lib. ' \
+          'Use `require` instead.'
+
+        def_node_matcher :require_relative, <<~PATTERN
+          (send nil? :require_relative
+            (str #target_falls_in_lib?))
+        PATTERN
+
+        # Extended from the Base class.
+        # More about the `#on_new_investigation` method can be found here:
+        # https://github.com/rubocop-hq/rubocop/blob/343f62e4555be0470326f47af219689e21c61a37/lib/rubocop/cop/base.rb
+        #
+        # Processing of the AST happens here.
+        def on_new_investigation
+          @file_path = processed_source.file_path
+          @file_directory = File.dirname(@file_path)
+        end
+
+        # Extended from AST::Traversal.
+        # More about the `#on_send` method can be found here:
+        # https://github.com/rubocop-hq/rubocop-ast/blob/08d0f49a47af1e9a30a6d8f67533ba793c843d67/lib/rubocop/ast/traversal.rb#L112
+        def on_send(node)
+          return unless require_relative(node)
+
+          add_offense(node)
+        end
+
+        # This method is called from inside `#def_node_matcher`.
+        # It is used to find paths which starts with "lib".
+        def target_falls_in_lib?(str)
+          root_dir = RuboCop::ConfigLoader.project_root
+          File.expand_path(str, @file_directory).start_with?(root_dir + '/lib')
+        end
+      end
+    end
+  end
+end

lib/rubocop/cop/packaging_cops.rb

@@ -1,3 +1,4 @@
 # frozen_string_literal: true
 
 require_relative 'packaging/gemspec_git'
+require_relative 'packaging/relative_require_to_lib'

rubocop-packaging.gemspec

@@ -23,10 +23,10 @@ Gem::Specification.new do |spec|
 
   spec.required_ruby_version = Gem::Requirement.new('>= 2.3.0')
 
-  spec.add_development_dependency   'bump', '>= 0.8.0'
-  spec.add_development_dependency   'pry', '>= 0.13.0'
+  spec.add_development_dependency   'bump', '~> 0.8'
+  spec.add_development_dependency   'pry', '~> 0.13'
   spec.add_development_dependency   'rake', '~> 13.0'
   spec.add_development_dependency   'rspec', '~> 3.0'
   spec.add_development_dependency   'yard', '~> 0.9'
-  spec.add_runtime_dependency       'rubocop', '>= 0.75.0'
+  spec.add_runtime_dependency       'rubocop', '~> 0.88'
 end

spec/rubocop/cop/packaging/relative_require_to_lib_spec.rb

@@ -0,0 +1,94 @@
+# frozen_string_literal: true
+
+RSpec.describe RuboCop::Cop::Packaging::RelativeRequireToLib, :config do
+  let(:message) { RuboCop::Cop::Packaging::RelativeRequireToLib::MSG }
+
+  let(:project_root) { RuboCop::ConfigLoader.project_root }
+
+  context 'when `require_relative` call lies outside spec/' do
+    let(:filename) { "#{project_root}/spec/foo_spec.rb" }
+    let(:source) { 'require_relative "../lib/foo.rb"' }
+
+    it 'registers an offense' do
+      expect_offense(<<~RUBY, filename)
+        #{source}
+        #{'^' * source.length} #{message}
+      RUBY
+    end
+  end
+
+  context 'when `require_relative` call with nested path lies outside test/' do
+    let(:filename) { "#{project_root}/test/rubocop/cop/bar_spec.rb" }
+    let(:source) { 'require_relative "../../../lib/bar"' }
+
+    it 'registers an offense' do
+      expect_offense(<<~RUBY, filename)
+        #{source}
+        #{'^' * source.length} #{message}
+      RUBY
+    end
+  end
+
+  context 'when one `require_relative` call lies outside specs/' do
+    let(:filename) { "#{project_root}/specs/baz_spec.rb" }
+    let(:source) { <<~RUBY.chomp }
+      require_relative 'spec_helper'
+      require_relative '../lib/rubocop/baz'
+    RUBY
+
+    it 'registers an offense' do
+      expect_offense(<<~RUBY, filename)
+        #{source}
+        #{'^' * 37} #{message}
+      RUBY
+    end
+  end
+
+  context 'when `require_relative` call with `unshift` lies outside tests/' do
+    let(:filename) { "#{project_root}/tests/qux_spec.rb" }
+    let(:source) { <<~RUBY.chomp }
+      $:.unshift('../lib')
+      require_relative "../lib/qux"
+    RUBY
+
+    it 'registers an offense' do
+      expect_offense(<<~RUBY, filename)
+        #{source}
+        #{'^' * 29} #{message}
+      RUBY
+    end
+  end
+
+  context 'when the `require_relative` call to `lib` lies inside spec/' do
+    let(:filename) { "#{project_root}/spec/rubocop/cop/foo_spec.rb" }
+    let(:source) { 'require_relative "../lib/foo"' }
+
+    it 'does not register an offense' do
+      expect_no_offenses(<<~RUBY, filename)
+        #{source}
+      RUBY
+    end
+  end
+
+  context 'when the `require_relative` call lies inside tests/' do
+    let(:filename) { "#{project_root}/tests/rubocop/cop/bar_spec.rb" }
+    let(:source) { 'require_relative "../bar"' }
+
+    it 'does not register an offense' do
+      expect_no_offenses(<<~RUBY, filename)
+        #{source}
+      RUBY
+    end
+  end
+
+  context 'when the `require_relative` call lies inside test/' do
+    let(:filename) { "#{project_root}/test/qux_spec.rb" }
+    let(:source) { 'require_relative "spec/rubocop/qux.rb"' }
+
+    it 'does not register an offense' do
+      expect_no_offenses(<<~RUBY, filename)
+        #{source}
+      RUBY
+    end
+  end
+end