Use rubocop-jekyll to enforce Jekyll's styles (#497)

To stop inheriting `rubocop.yml` from the *latest* version of Jekyll as that may cause false CI failures for PRs in this project.

Miscellaneous developmental changes include:
- adding support for Bundler 2.0
- dropping test coverage for EOL Ruby 2.3 and older.

Author: ashmaroli

.gitignore

@@ -1,4 +1,5 @@
 _site/
+.gems/
 .sass-cache/
 .jekyll-metadata
 /.bundle/

.rubocop.yml

@@ -1,13 +1,12 @@
+require: 'rubocop-jekyll'
 inherit_gem:
-  jekyll: .rubocop.yml
+  rubocop-jekyll: '.rubocop.yml'
 
 AllCops:
   Exclude:
     - lib/jekyll-admin/public/**/*
     - src/**/*
     - node_modules/**/*
-    - Gemfile
-    - jekyll-admin.gemspec
 
 Metrics/BlockLength:
   Enabled: false

.travis.yml

@@ -1,15 +1,15 @@
 language: ruby
-rvm: 2.2
+rvm: 2.4
 before_install:
   - nvm install 6
+  - gem update --system --no-document
 install: script/bootstrap
 script: script/cibuild
 cache:
   bundler: true
   yarn: true
   directories:
     - node_modules
-sudo: false
 env:
   matrix:
     - TEST_SUITE=node

Gemfile

@@ -1,8 +1,8 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
 # Specify your gem's dependencies in jekyll-admin.gemspec
 gemspec
 
 # Site dependencies
-gem 'jekyll-seo-tag'
-gem 'jekyll-sitemap'
+gem "jekyll-seo-tag"
+gem "jekyll-sitemap"

jekyll-admin.gemspec

@@ -1,41 +1,39 @@
-# coding: utf-8
-lib = File.expand_path('../lib', __FILE__)
+lib = File.expand_path("lib", __dir__)
 $LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
-require 'jekyll-admin/version'
+require "jekyll-admin/version"
 
 Gem::Specification.new do |spec|
   spec.name          = "jekyll-admin"
   spec.version       = JekyllAdmin::VERSION
   spec.authors       = ["Mert Kahyaoğlu", "GitHub Open Source"]
   spec.email         = ["[email protected]", "[email protected]"]
 
-  spec.summary       = %q{wp-admin for Jekyll, but better}
-  spec.description   = %q{Jekyll::Admin is a drop in administrative framework for Jekyll sites.}
+  spec.summary       = "wp-admin for Jekyll, but better"
+  spec.description   = "Jekyll::Admin is a drop in administrative framework for Jekyll sites."
   spec.homepage      = "https://github.com/jekyll/jekyll-admin"
   spec.license       = "MIT"
 
   # Prevent pushing this gem to RubyGems.org. To allow pushes either set the 'allowed_push_host'
   # to allow pushing to a single host or delete this section to allow pushing to any host.
   if spec.respond_to?(:metadata)
-    spec.metadata['allowed_push_host'] = "https://rubygems.org"
+    spec.metadata["allowed_push_host"] = "https://rubygems.org"
   else
     raise "RubyGems 2.0 or newer is required to protect against public gem pushes."
   end
 
   spec.files         = Dir.glob("lib/**/*").concat(%w(LICENSE README.md))
   spec.bindir        = "exe"
-  spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
+  spec.executables   = spec.files.grep(%r!^exe/!) { |f| File.basename(f) }
   spec.require_paths = ["lib"]
 
   spec.add_dependency "jekyll", "~> 3.3"
   spec.add_dependency "sinatra", "~> 1.4"
   spec.add_dependency "sinatra-contrib", "~> 1.4"
-  spec.add_dependency "addressable", "~> 2.4"
 
-  spec.add_development_dependency "bundler", "~> 1.7"
+  spec.add_development_dependency "bundler", ">= 1.7"
+  spec.add_development_dependency "gem-release", "~> 0.7"
   spec.add_development_dependency "rake", "~> 10.0"
   spec.add_development_dependency "rspec", "~> 3.4"
-  spec.add_development_dependency "rubocop", "~> 0.57.2"
+  spec.add_development_dependency "rubocop-jekyll", "~> 0.10.0"
   spec.add_development_dependency "sinatra-cross_origin", "~> 0.3"
-  spec.add_development_dependency "gem-release", "~> 0.7"
 end

lib/jekyll-admin/apiable.rb

@@ -2,7 +2,6 @@ module JekyllAdmin
   # Abstract module to be included in Convertible and Document to provide
   # additional, API-specific functionality without duplicating logic
   module APIable
-
     CONTENT_FIELDS = %w(next previous content excerpt).freeze
 
     # Returns a hash suitable for use as an API response.
@@ -48,9 +47,7 @@ def to_api(include_content: false)
         output["name"] = basename
       end
 
-      if is_a?(Jekyll::StaticFile)
-        output["from_theme"] = from_theme_gem?
-      end
+      output["from_theme"] = from_theme_gem? if is_a?(Jekyll::StaticFile)
 
       output
     end
@@ -89,6 +86,7 @@ def file_read_options
 
     def front_matter
       return unless file_exists?
+
       @front_matter ||= if file_contents =~ Jekyll::Document::YAML_FRONT_MATTER_REGEXP
                           SafeYAML.load(Regexp.last_match(1))
                         else
@@ -98,6 +96,7 @@ def front_matter
 
     def raw_content
       return unless file_exists?
+
       @raw_content ||= if file_contents =~ Jekyll::Document::YAML_FRONT_MATTER_REGEXP
                          $POSTMATCH
                        else
@@ -111,6 +110,7 @@ def encoded_content
 
     def file_exists?
       return @file_exists if defined? @file_exists
+
       @file_exists = File.exist?(file_path)
     end
 
@@ -153,6 +153,7 @@ def content_fields
 
     def url_fields
       return {} unless respond_to?(:http_url) && respond_to?(:api_url)
+
       {
         "http_url" => http_url,
         "api_url"  => api_url,

lib/jekyll-admin/data_file.rb

@@ -14,7 +14,7 @@ class DataFile
     #
     # id - the file ID as passed from the API. This may or may not have an extension
     def initialize(id)
-      @id ||= File.extname(id).empty? ? "#{id}.yml" : id
+      @id = File.extname(id).empty? ? "#{id}.yml" : id
     end
     alias_method :relative_path, :id
 

lib/jekyll-admin/directory.rb

@@ -63,6 +63,7 @@ def directories
       path.entries.map do |entry|
         next if [".", ".."].include? entry.to_s
         next unless path.join(entry).directory?
+
         self.class.new(
           path.join(entry),
           :base => base, :content_type => content_type, :splat => splat

lib/jekyll-admin/file_helper.rb

@@ -1,6 +1,5 @@
 module JekyllAdmin
   module FileHelper
-
     # The file the user requested in the URL
     def requested_file
       find_by_path(path)

lib/jekyll-admin/path_helper.rb

@@ -45,6 +45,7 @@ def relative_write_path
     # Is this request renaming a file?
     def renamed?
       return false unless request_payload["path"]
+
       ensure_leading_slash(request_payload["path"]) != relative_path
     end
 
@@ -68,6 +69,7 @@ def directory_path
 
     def ensure_leading_slash(input)
       return input if input.nil? || input.empty? || input.start_with?("/")
+
       "/#{input}"
     end