Enable Rubocop Style/StringConcatenation defaults (#23792)

.rubocop_todo.yml

@@ -2263,25 +2263,6 @@ Style/SlicingWithRange:
     - 'lib/mastodon/premailer_webpack_strategy.rb'
     - 'lib/tasks/repo.rake'
 
-# Offense count: 25
-# This cop supports unsafe autocorrection (--autocorrect-all).
-# Configuration parameters: Mode.
-Style/StringConcatenation:
-  Exclude:
-    - 'app/lib/activitypub/case_transform.rb'
-    - 'app/lib/validation_error_formatter.rb'
-    - 'app/services/backup_service.rb'
-    - 'app/services/fetch_link_card_service.rb'
-    - 'lib/mastodon/emoji_cli.rb'
-    - 'lib/mastodon/redis_config.rb'
-    - 'lib/mastodon/snowflake.rb'
-    - 'lib/paperclip/gif_transcoder.rb'
-    - 'lib/paperclip/type_corrector.rb'
-    - 'spec/controllers/api/v1/apps_controller_spec.rb'
-    - 'spec/controllers/api/v1/streaming_controller_spec.rb'
-    - 'spec/validators/disallowed_hashtags_validator_spec.rb'
-    - 'spec/workers/web/push_notification_worker_spec.rb'
-
 # Offense count: 272
 # This cop supports safe autocorrection (--autocorrect).
 # Configuration parameters: EnforcedStyle, MinSize.

app/lib/activitypub/case_transform.rb

@@ -13,7 +13,7 @@ module ActivityPub::CaseTransform
       when Symbol then camel_lower(value.to_s).to_sym
       when String
         camel_lower_cache[value] ||= if value.start_with?('_:')
-                                       '_:' + value.gsub(/\A_:/, '').underscore.camelize(:lower)
+                                       "_:#{value.gsub(/\A_:/, '').underscore.camelize(:lower)}"
                                      else
                                        value.underscore.camelize(:lower)
                                      end

app/lib/validation_error_formatter.rb

@@ -19,7 +19,7 @@ class ValidationErrorFormatter
       messages = errors.messages[attribute_name]
 
       h[@aliases[attribute_name] || attribute_name] = attribute_errors.map.with_index do |error, index|
-        { error: 'ERR_' + error[:error].to_s.upcase, description: messages[index] }
+        { error: "ERR_#{error[:error].to_s.upcase}", description: messages[index] }
       end
     end
 

app/services/backup_service.rb

@@ -53,7 +53,7 @@ class BackupService < BaseService
       end
     end
 
-    archive_filename = ['archive', Time.now.utc.strftime('%Y%m%d%H%M%S'), SecureRandom.hex(16)].join('-') + '.tar.gz';
+    archive_filename = "#{['archive', Time.now.utc.strftime('%Y%m%d%H%M%S'), SecureRandom.hex(16)].join('-')}.tar.gz";
 
     @backup.dump      = ActionDispatch::Http::UploadedFile.new(tempfile: tmp_file, filename: archive_filename)
     @backup.processed = true
@@ -86,14 +86,14 @@ class BackupService < BaseService
   def dump_actor!(tar)
     actor = serialize(account, ActivityPub::ActorSerializer)
 
-    actor[:icon][:url]  = 'avatar' + File.extname(actor[:icon][:url])  if actor[:icon]
-    actor[:image][:url] = 'header' + File.extname(actor[:image][:url]) if actor[:image]
+    actor[:icon][:url]  = "avatar#{File.extname(actor[:icon][:url])}"  if actor[:icon]
+    actor[:image][:url] = "header#{File.extname(actor[:image][:url])}" if actor[:image]
     actor[:outbox]      = 'outbox.json'
     actor[:likes]       = 'likes.json'
     actor[:bookmarks]   = 'bookmarks.json'
 
-    download_to_tar(tar, account.avatar, 'avatar' + File.extname(account.avatar.path)) if account.avatar.exists?
-    download_to_tar(tar, account.header, 'header' + File.extname(account.header.path)) if account.header.exists?
+    download_to_tar(tar, account.avatar, "avatar#{File.extname(account.avatar.path)}") if account.avatar.exists?
+    download_to_tar(tar, account.header, "header#{File.extname(account.header.path)}") if account.header.exists?
 
     json = Oj.dump(actor)
 

app/services/fetch_link_card_service.rb

@@ -45,7 +45,7 @@ class FetchLinkCardService < BaseService
   def html
     return @html if defined?(@html)
 
-    Request.new(:get, @url).add_headers('Accept' => 'text/html', 'User-Agent' => Mastodon::Version.user_agent + ' Bot';).perform do |res|
+    Request.new(:get, @url).add_headers('Accept' => 'text/html', 'User-Agent' => "#{Mastodon::Version.user_agent} Bot";).perform do |res|
       # We follow redirects, and ideally we want to save the preview card for
       # the destination URL and not any link shortener in-between, so here
       # we set the URL to the one of the last response in the redirect chain

lib/mastodon/emoji_cli.rb

@@ -68,7 +68,7 @@ module Mastodon
             failed += 1
             say('Failure/Error: ', :red)
             say(entry.full_name)
-            say('    ' + custom_emoji.errors[:image].join(', '), :red)
+            say("    #{custom_emoji.errors[:image].join(', ')}", :red)
           end
         end
       end

lib/mastodon/redis_config.rb

@@ -1,17 +1,17 @@
 # frozen_string_literal: true
 
 def setup_redis_env_url(prefix = nil, defaults = true)
-  prefix = prefix.to_s.upcase + '_'; unless prefix.nil?
+  prefix = "#{prefix.to_s.upcase}_"; unless prefix.nil?
   prefix = '' if prefix.nil?
 
-  return if ENV[prefix + 'REDIS_URL';].present?
+  return if ENV["#{prefix}REDIS_URL";].present?
 
-  password = ENV.fetch(prefix + 'REDIS_PASSWORD';) { '' if defaults }
-  host     = ENV.fetch(prefix + 'REDIS_HOST';) { 'localhost' if defaults }
-  port     = ENV.fetch(prefix + 'REDIS_PORT';) { 6379 if defaults }
-  db       = ENV.fetch(prefix + 'REDIS_DB';) { 0 if defaults }
+  password = ENV.fetch("#{prefix}REDIS_PASSWORD";) { '' if defaults }
+  host     = ENV.fetch("#{prefix}REDIS_HOST";) { 'localhost' if defaults }
+  port     = ENV.fetch("#{prefix}REDIS_PORT";) { 6379 if defaults }
+  db       = ENV.fetch("#{prefix}REDIS_DB";) { 0 if defaults }
 
-  ENV[prefix + 'REDIS_URL';] = begin
+  ENV["#{prefix}REDIS_URL";] = begin
     if [password, host, port, db].all?(&:nil?)
       ENV['REDIS_URL']
     else
@@ -27,7 +27,7 @@ setup_redis_env_url(:cache, false)
 setup_redis_env_url(:sidekiq, false)
 
 namespace         = ENV.fetch('REDIS_NAMESPACE', nil)
-cache_namespace   = namespace ? namespace + '_cache'; : 'cache'
+cache_namespace   = namespace ? "#{namespace}_cache"; : 'cache'
 sidekiq_namespace = namespace
 
 REDIS_CACHE_PARAMS = {

lib/mastodon/snowflake.rb

@@ -115,7 +115,7 @@ module Mastodon::Snowflake
         # And only those that are using timestamp_id.
         next unless (data = DEFAULT_REGEX.match(id_col.default_function))
 
-        seq_name = data[:seq_prefix] + '_id_seq';
+        seq_name = "#{data[:seq_prefix]}_id_seq";
 
         # If we were on Postgres 9.5+, we could do CREATE SEQUENCE IF
         # NOT EXISTS, but we can't depend on that. Instead, catch the

lib/paperclip/gif_transcoder.rb

@@ -109,7 +109,7 @@ module Paperclip
       final_file = Paperclip::Transcoder.make(file, options, attachment)
 
       if options[:style] == :original
-        attachment.instance.file_file_name    = File.basename(attachment.instance.file_file_name, '.*') + '.mp4';
+        attachment.instance.file_file_name    = "#{File.basename(attachment.instance.file_file_name, '.*')}.mp4";
         attachment.instance.file_content_type = 'video/mp4'
         attachment.instance.type              = MediaAttachment.types[:gifv]
       end

lib/paperclip/type_corrector.rb

@@ -7,7 +7,7 @@ module Paperclip
     def make
       return @file unless options[:format]
 
-      target_extension = '.' + options[:format]
+      target_extension = ".#{options[:format]}"
       extension        = File.extname(attachment.instance_read(:file_name))
 
       return @file unless options[:style] == :original && target_extension && extension != target_extension

spec/controllers/api/v1/apps_controller_spec.rb

@@ -68,7 +68,7 @@ RSpec.describe Api::V1::AppsController, type: :controller do
     end
 
     context 'with a too-long website' do
-      let(:website) { 'https://foo.bar/' + ('hoge' * 2_000) }
+      let(:website) { "https://foo.bar/#{'hoge' * 2_000}" }
 
       it 'returns http unprocessable entity' do
         expect(response).to have_http_status(422)
@@ -76,7 +76,7 @@ RSpec.describe Api::V1::AppsController, type: :controller do
     end
 
     context 'with a too-long redirect_uris' do
-      let(:redirect_uris) { 'https://foo.bar/' + ('hoge' * 2_000) }
+      let(:redirect_uris) { "https://foo.bar/#{'hoge' * 2_000}" }
 
       it 'returns http unprocessable entity' do
         expect(response).to have_http_status(422)

spec/controllers/api/v1/streaming_controller_spec.rb

@@ -25,7 +25,7 @@ describe Api::V1::StreamingController do
 
   context 'with streaming api on different host' do
     before(:each) do
-      Rails.configuration.x.streaming_api_base_url = 'wss://streaming-' + Rails.configuration.x.web_domain
+      Rails.configuration.x.streaming_api_base_url = "wss://streaming-#{Rails.configuration.x.web_domain}"
       @streaming_host = URI.parse(Rails.configuration.x.streaming_api_base_url).host
     end
 

spec/validators/disallowed_hashtags_validator_spec.rb

@@ -11,7 +11,7 @@ RSpec.describe DisallowedHashtagsValidator, type: :validator do
       described_class.new.validate(status)
     end
 
-    let(:status) { double(errors: errors, local?: local, reblog?: reblog, text: disallowed_tags.map { |x| '#' + x }.join(' ')) }
+    let(:status) { double(errors: errors, local?: local, reblog?: reblog, text: disallowed_tags.map { |x| "##{x}" }.join(' ')) }
     let(:errors) { double(add: nil) }
 
     context 'for a remote reblog' do

spec/workers/web/push_notification_worker_spec.rb

@@ -37,7 +37,7 @@ describe Web::PushNotificationWorker do
       expect(a_request(:post, endpoint).with(headers: {
         'Content-Encoding' => 'aesgcm',
         'Content-Type' => 'application/octet-stream',
-        'Crypto-Key' => 'dh=BAgtUks5d90kFmxGevk9tH7GEmvz9DB0qcEMUsOBgKwMf-TMjsKIIG6LQvGcFAf6jcmAod15VVwmYwGIIxE4VWE;p256ecdsa=' + vapid_public_key.delete('='),
+        'Crypto-Key' => "dh=BAgtUks5d90kFmxGevk9tH7GEmvz9DB0qcEMUsOBgKwMf-TMjsKIIG6LQvGcFAf6jcmAod15VVwmYwGIIxE4VWE;p256ecdsa=#{vapid_public_key.delete('=')}",
         'Encryption' => 'salt=WJeVM-RY-F9351SVxTFx_g',
         'Ttl' => '172800',
         'Urgency' => 'normal',