ADD rubocop (#95)

This adds some linting to the project.

Details
* ADD `rubocop` on project and travis
* ADD `memoist` to ease thing

.rubocop.yml

@@ -0,0 +1,8 @@
+AllCops:
+  TargetRubyVersion: 2.5
+
+Metrics/BlockLength:
+  ExcludedMethods: ['describe', 'context']
+
+Metrics/LineLength:
+  Max: 100

.travis.yml

@@ -5,5 +5,6 @@ before_install:
 rvm:
   - 2.6.0
   - 2.5.0
-  - 2.4.0
-  - 2.3.0
+script:
+  - bundle exec rspec
+  - bundle exec rubocop

CHANGELOG.md

@@ -1,11 +1,15 @@
 # Unreleased
 
+Deprecations:
+* ruby 2.4 and below are now deprecated
+
 Updates:
 * gems and dependencies
 
 Development tools:
 * add CI support for ruby 2.6.0
 * add sleep stub in specs
+* add rubocop
 
 # v3.0.0 (March 10, 2018)
 

Gemfile

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 source 'https://rubygems.org'
 
 gemspec

Gemfile.lock

@@ -4,19 +4,27 @@ PATH
     gem_updater (3.0.0)
       bundler (~> 1.16)
       json (~> 2.1)
+      memoist (~> 0.16.0)
       nokogiri (~> 1.8)
 
 GEM
   remote: https://rubygems.org/
   specs:
+    ast (2.4.0)
     codacy-coverage (2.1.0)
       simplecov
     diff-lcs (1.3)
     docile (1.3.1)
+    jaro_winkler (1.5.2)
     json (2.1.0)
+    memoist (0.16.0)
     mini_portile2 (2.4.0)
-    nokogiri (1.10.1)
+    nokogiri (1.10.3)
       mini_portile2 (~> 2.4.0)
+    parallel (1.17.0)
+    parser (2.6.3.0)
+      ast (~> 2.4.0)
+    rainbow (3.0.0)
     rake (12.3.2)
     rspec (3.8.0)
       rspec-core (~> 3.8.0)
@@ -31,11 +39,20 @@ GEM
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.8.0)
     rspec-support (3.8.0)
+    rubocop (0.68.1)
+      jaro_winkler (~> 1.5.1)
+      parallel (~> 1.10)
+      parser (>= 2.5, != 2.5.1.1)
+      rainbow (>= 2.2.2, < 4.0)
+      ruby-progressbar (~> 1.7)
+      unicode-display_width (>= 1.4.0, < 1.6)
+    ruby-progressbar (1.10.0)
     simplecov (0.16.1)
       docile (~> 1.1)
       json (>= 1.8, < 3)
       simplecov-html (~> 0.10.0)
     simplecov-html (0.10.2)
+    unicode-display_width (1.5.0)
 
 PLATFORMS
   ruby
@@ -45,6 +62,7 @@ DEPENDENCIES
   gem_updater!
   rake
   rspec (~> 3.7)
+  rubocop (~> 0.68.1)
   simplecov
 
 BUNDLED WITH

Rakefile

@@ -1,8 +1,10 @@
+# frozen_string_literal: true
+
 require 'bundler/setup'
 require 'bundler/gem_tasks'
 require 'rspec/core/rake_task'
 
 RSpec::Core::RakeTask.new
 
 desc 'Default: run the rspec examples'
-task :default => :spec
+task default: :spec

bin/gem_update

@@ -1,10 +1,12 @@
+# frozen_string_literal: true
+
 #!/usr/bin/env ruby
 require 'optparse'
 
 # Exit cleanly from an early interrupt
 Signal.trap('INT') { exit 1 }
 
-$LOAD_PATH.unshift File.expand_path('../../lib', __FILE__)
+$LOAD_PATH.unshift File.expand_path('../lib', __dir__)
 require 'gem_updater'
 
 Bundler.ui = Bundler::UI::Shell.new

gem_updater.gemspec

@@ -1,22 +1,27 @@
+# frozen_string_literal: true
+
 Gem::Specification.new do |s|
   s.name        = 'gem_updater'
   s.version     = '3.0.0'
   s.date        = '2018-03-10'
   s.summary     = 'Update your gems and find their changelogs'
-  s.description = 'Updates the gems of your Gemfile and fetches the links pointing to where their changelogs are'
+  s.description = 'Updates the gems of your Gemfile ' \
+                  'and fetches the links pointing to where their changelogs are'
   s.authors     = ['Maxime Demolin']
   s.email       = 'akbarova.armia@gmail.com'
-  s.files       = Dir["{lib}/**/*"]
+  s.files       = Dir['{lib}/**/*']
   s.homepage    = 'https://github.com/MaximeD/gem_updater'
   s.license     = 'MIT'
 
-  s.required_ruby_version = '>= 2.3.0'
+  s.required_ruby_version = '>= 2.5.0'
 
-  s.add_runtime_dependency 'bundler',   '~> 1.16'
-  s.add_runtime_dependency 'json',      '~> 2.1'
-  s.add_runtime_dependency 'nokogiri',  '~> 1.8'
+  s.add_runtime_dependency 'bundler',  '~> 1.16'
+  s.add_runtime_dependency 'json',     '~> 2.1'
+  s.add_runtime_dependency 'memoist',  '~> 0.16.0'
+  s.add_runtime_dependency 'nokogiri', '~> 1.8'
 
-  s.add_development_dependency 'rspec', '~> 3.7'
+  s.add_development_dependency 'rspec',   '~> 3.7'
+  s.add_development_dependency 'rubocop', '~> 0.68.1'
 
   s.executables << 'gem_update'
 end

lib/gem_updater.rb

@@ -1,12 +1,17 @@
+# frozen_string_literal: true
+
+require 'memoist'
 require 'gem_updater/gem_file'
 require 'gem_updater/ruby_gems_fetcher'
 require 'gem_updater/source_page_parser'
 
+# Base lib.
 module GemUpdater
-
   # Updater's main responsability is to fill changes
   # happened before and after update of `Gemfile`, and then format them.
   class Updater
+    extend Memoist
+
     attr_accessor :gemfile
 
     def initialize
@@ -43,23 +48,11 @@ def format_diff
 
     # For each gem, retrieve its changelog
     def fill_changelogs
-      threads = []
-
-      gemfile.changes.each do |gem_name, details|
-        threads << Thread.new do
-          if source_uri = find_source(gem_name, details[:source])
-            source_page = GemUpdater::SourcePageParser.new(
-              url: source_uri, version: details[:versions][:new]
-            )
-
-            if source_page.changelog
-              gemfile.changes[gem_name][:changelog] = source_page.changelog
-            end
-          end
+      [].tap do |threads|
+        gemfile.changes.each do |gem_name, details|
+          threads << Thread.new { retrieve_gem_changes(gem_name, details) }
         end
-      end
-
-      threads.each(&:join)
+      end.each(&:join)
     end
 
     # Find where is hosted the source of a gem
@@ -76,16 +69,26 @@ def find_source(gem, source)
       end
     end
 
+    def retrieve_gem_changes(gem_name, details)
+      source_uri = find_source(gem_name, details[:source])
+      return unless source_uri
+
+      source_page = GemUpdater::SourcePageParser.new(
+        url: source_uri, version: details[:versions][:new]
+      )
+
+      gemfile.changes[gem_name][:changelog] = source_page.changelog if source_page.changelog
+    end
+
     # Get the template for gem's diff.
     # It can use a custom template.
     #
     # @return [ERB] the template
     def template
-      @template ||= begin
-        File.read("#{Dir.home}/.gem_updater_template.erb")
-      rescue Errno::ENOENT
-        File.read(File.expand_path('../../lib/gem_updater_template.erb', __FILE__))
-      end
+      File.read("#{Dir.home}/.gem_updater_template.erb")
+    rescue Errno::ENOENT
+      File.read(File.expand_path('../lib/gem_updater_template.erb', __dir__))
     end
+    memoize :template
   end
 end

lib/gem_updater/gem_file.rb

@@ -1,7 +1,8 @@
+# frozen_string_literal: true
+
 require 'bundler/cli'
 
 module GemUpdater
-
   # GemFile is responsible for handling `Gemfile`
   class GemFile
     attr_accessor :changes
@@ -21,21 +22,20 @@ def update!(gems)
     #
     # @return [Hash] gems for which there are differences.
     def compute_changes
-      get_spec_sets
+      spec_sets_diff!
 
       old_spec_set.each do |old_gem|
         updated_gem = new_spec_set.find { |new_gem| new_gem.name == old_gem.name }
+        next unless updated_gem && old_gem.version != updated_gem.version
 
-        if updated_gem && old_gem.version != updated_gem.version
-          fill_changes(old_gem, updated_gem)
-        end
+        fill_changes(old_gem, updated_gem)
       end
     end
 
     private
 
     # Get the two spec sets (before and after `bundle update`)
-    def get_spec_sets
+    def spec_sets_diff!
       @old_spec_set = spec_set
       reinitialize_spec_set!
       @new_spec_set = spec_set

lib/gem_updater/ruby_gems_fetcher.rb

@@ -1,12 +1,13 @@
+# frozen_string_literal: true
+
 require 'json'
 require 'nokogiri'
 require 'open-uri'
 
 module GemUpdater
-
   # RubyGemsFetcher is a wrapper around rubygems API.
   class RubyGemsFetcher
-    HTTP_TOO_MANY_REQUESTS = '429'.freeze
+    HTTP_TOO_MANY_REQUESTS = '429'
     GEM_HOMEPAGES = %w[source_code_uri homepage_uri].freeze
 
     attr_reader :gem_name, :source
@@ -35,11 +36,10 @@ def source_uri
     def uri_from_rubygems
       return unless source.remotes.map(&:host).include?('rubygems.org')
 
-      if response = query_rubygems
-        response[
-          GEM_HOMEPAGES.find { |key| response[key] && !response[key].empty? }
-        ]
-      end
+      response = query_rubygems
+      return unless response
+
+      response[GEM_HOMEPAGES.find { |key| response[key] && !response[key].empty? }]
     end
 
     # Make the real query to rubygems
@@ -52,14 +52,15 @@ def query_rubygems(tries = 0)
       # We may trigger too many requests, in which case give rubygems a break
       if e.io.status.include?(HTTP_TOO_MANY_REQUESTS)
         if (tries += 1) < 2
-          sleep 1 and retry
+          sleep 1 && retry
         end
       end
     end
 
     # Look if gem can be found in another remote
     #
     # @return [String|nil] uri of source code
+    # rubocop:disable Metrics/MethodLength
     def uri_from_other_sources
       uri = nil
       source.remotes.each do |remote|
@@ -70,24 +71,28 @@ def uri_from_other_sources
               when 'rails-assets.org'
                 uri_from_railsassets
               else
-                Bundler.ui.error "Source #{remote} is not supported, feel free to open a PR or an issue on https://github.com/MaximeD/gem_updater"
+                Bundler.ui.error "Source #{remote} is not supported, ' \
+                  'feel free to open a PR or an issue on https://github.com/MaximeD/gem_updater"
               end
       end
 
       uri
     end
+    # rubocop:enable Metrics/MethodLength
 
     # Ask rails-assets.org for source uri of gem.
     # API is at : https://rails-assets.org/packages/package_name
     #
     # @return [String|nil] uri of source code
     def uri_from_railsassets
-      if response = query_railsassets
-        response['url'].gsub(/^git/, 'http')
-      end
+      response = query_railsassets
+      return unless response
+
+      response['url'].gsub(/^git/, 'http')
     end
 
     # Make the real query to railsassets
+    # rubocop:disable Lint/HandleExceptions
     def query_railsassets
       JSON.parse(
         open(
@@ -99,5 +104,6 @@ def query_railsassets
       # with html (instead of json) containing a 500...
     rescue OpenURI::HTTPError
     end
+    # rubocop:enable Lint/HandleExceptions
   end
 end