Add rubocop integration

Author: joe-re

Dockerfile.development

@@ -8,6 +8,7 @@ RUN mkdir /app /vendor && chown -R ruby:ruby /app /vendor
 ENV LANG=C.UTF-8 \
   BUNDLE_PATH=/vendor/bundle/$RUBY_VERSION \
   BUNDLE_JOBS=4
+ENV PATH=$PATH:/vendor/bundle/$RUBY_VERSION/bin
 
 USER ruby
 WORKDIR /app

bin/setup

@@ -4,3 +4,5 @@ IFS=$'\n\t'
 set -vx
 
 bundle install
+
+# Do any other automated setup that you need to do here

lib/language_server.rb

@@ -2,6 +2,7 @@
 require "language_server/logger"
 require "language_server/protocol"
 require "language_server/linter/ruby_wc"
+require "language_server/linter/rubocop"
 require "language_server/completion_provider/rcodetools"
 require "language_server/completion_provider/ad_hoc"
 require "language_server/definition_provider/ad_hoc"
@@ -90,11 +91,13 @@ def on(method, &callback)
 
   on :"textDocument/didChange" do |request:, notifier:, file_store:, project:|
     uri = request[:params][:textDocument][:uri]
+    filePath = uri.match(/^file:\/\/(.*\.rb)/)[1]
     text = request[:params][:contentChanges][0][:text]
     file_store.cache(uri, text)
     project.recalculate_result(uri)
+    diagnostics = (Linter::Rubocop.new(filePath).call + Linter::RubyWC.new(text).call).flatten
 
-    diagnostics = Linter::RubyWC.new(text).call.map do |error|
+    diagnostics = diagnostics.map do |error|
       Protocol::Interface::Diagnostic.new(
         message: error.message,
         severity: error.warning? ? Protocol::Constant::DiagnosticSeverity::WARNING : Protocol::Constant::DiagnosticSeverity::ERROR,

lib/language_server/linter/rubocop.rb

@@ -0,0 +1,38 @@
+require "open3"
+
+module LanguageServer
+  module Linter
+    class Rubocop
+      def initialize(path, config_path="")
+        @path = path
+        @config_path = config_path
+      end
+
+      def call
+        Bundler.with_clean_env do
+          command = "rubocop #{@path} --format json --force-exclusion"
+          command += " --config #{@config_path}" if @config_path != ""
+          o, err, _ = Open3.capture3(command)
+          return [Error.new(line_num: 0, message: err, type: 'error')] if err != ""
+          JSON
+            .parse(o)['files'].map { |v| v['offenses'] }
+            .flatten
+            .map { |v| Error.new(line_num: v['location']['line'].to_i - 1, message: v['message'], type: convert_type(v['severity'])) }
+        end
+      end
+
+      private
+
+      def convert_type(type)
+        case type
+        when 'refactor' then 'warning'
+        when 'convention' then 'warning'
+        when 'warning' then 'warning'
+        when 'error' then 'error'
+        when 'fatal' then 'error'
+        end
+      end
+
+    end
+  end
+end

test/fixtures/rubocop.yml

@@ -0,0 +1,7 @@
+AllCops:
+  DisabledByDefault: true
+
+Lint/UselessAssignment:
+  Enabled: true
+StringLiterals:
+  EnforcedStyle: single_quotes

test/language_server/linter/rubocop_test.rb

@@ -0,0 +1,54 @@
+require 'test_helper'
+
+module LanguageServer::Linter
+  class RubocopTest < Minitest::Test
+    def setup
+      @config_path = File.expand_path('./../../../fixtures/rubocop.yml', __FILE__)
+    end
+
+    def test_fatal_error
+      file = Tempfile.open(['bar_', '.rb']) do |v|
+        v.puts 'require "foo'
+        v
+      end
+
+      actual = Rubocop.new(file.path, @config_path).call
+
+      assert do
+        actual == [
+          Error.new(
+            line_num: 0,
+            message: "unterminated string meets end of file\n(Using Ruby 2.1 parser; configure using `TargetRubyVersion` parameter, under `AllCops`)",
+            type: 'error'
+          )
+        ]
+      end
+    end
+
+    def test_warning_error
+      file = Tempfile.open(['bar_', '.rb']) do |v|
+        v.puts "a = 'a'"
+        v
+      end
+
+      actual = Rubocop.new(file.path, @config_path).call
+
+      assert do
+        actual.first == Error.new(line_num: 0, message: "Useless assignment to variable - `a`.", type: 'warning')
+      end
+    end
+
+    def test_convention_error
+      file = Tempfile.open(['bar_', '.rb']) do |v|
+        v.puts 'require "foo"'
+        v
+      end
+
+      actual = Rubocop.new(file.path, @config_path).call
+
+      assert do
+        actual.first == Error.new(line_num: 0, message: "Prefer single-quoted strings when you don't need string interpolation or special symbols.", type: 'warning')
+      end
+    end
+  end
+end