Remove deprecated `mb_chars` method

app/lib/hashtag_normalizer.rb

@@ -16,7 +16,7 @@ class HashtagNormalizer
   end
 
   def lowercase(str)
-    str.mb_chars.downcase.to_s
+    str.downcase.to_s
   end
 
   def cjk_width(str)

app/models/tag.rb

@@ -160,11 +160,11 @@ class Tag < ApplicationRecord
   private
 
   def validate_name_change
-    errors.add(:name, I18n.t('tags.does_not_match_previous_name')) unless name_was.mb_chars.casecmp(name.mb_chars).zero?
+    errors.add(:name, I18n.t('tags.does_not_match_previous_name')) unless name_was.casecmp(name).zero?
   end
 
   def validate_display_name_change
-    unless HashtagNormalizer.new.normalize(display_name).casecmp(name.mb_chars).zero?
+    unless HashtagNormalizer.new.normalize(display_name).casecmp(name).zero?
       errors.add(:display_name,
                  I18n.t('tags.does_not_match_previous_name'))
     end

app/services/batched_remove_status_service.rb

@@ -92,7 +92,7 @@ class BatchedRemoveStatusService < BaseService
       pipeline.publish(status.local? ? 'timeline:public:local:media' : 'timeline:public:remote:media', payload)
     end
 
-    status.tags.map { |tag| tag.name.mb_chars.downcase }.each do |hashtag|
+    status.tags.map { |tag| tag.name.downcase }.each do |hashtag|
       pipeline.publish("timeline:hashtag:#{hashtag}", payload)
       pipeline.publish("timeline:hashtag:#{hashtag}:local", payload) if status.local?
     end

app/services/fan_out_on_write_service.rb

@@ -128,8 +128,8 @@ class FanOutOnWriteService < BaseService
 
   def broadcast_to_hashtag_streams!
     @status.tags.map(&:name).each do |hashtag|
-      redis.publish("timeline:hashtag:#{hashtag.mb_chars.downcase}", anonymous_payload)
-      redis.publish("timeline:hashtag:#{hashtag.mb_chars.downcase}:local", anonymous_payload) if @status.local?
+      redis.publish("timeline:hashtag:#{hashtag.downcase}", anonymous_payload)
+      redis.publish("timeline:hashtag:#{hashtag.downcase}:local", anonymous_payload) if @status.local?
     end
   end
 

app/services/remove_status_service.rb

@@ -123,8 +123,8 @@ class RemoveStatusService < BaseService
     return if skip_streaming?
 
     @status.tags.map(&:name).each do |hashtag|
-      redis.publish("timeline:hashtag:#{hashtag.mb_chars.downcase}", @payload)
-      redis.publish("timeline:hashtag:#{hashtag.mb_chars.downcase}:local", @payload) if @status.local?
+      redis.publish("timeline:hashtag:#{hashtag.downcase}", @payload)
+      redis.publish("timeline:hashtag:#{hashtag.downcase}:local", @payload) if @status.local?
     end
   end
 

app/validators/note_length_validator.rb

@@ -8,7 +8,7 @@ class NoteLengthValidator < ActiveModel::EachValidator
   private
 
   def too_long?(value)
-    countable_text(value).mb_chars.grapheme_length > options[:maximum]
+    countable_text(value).length > options[:maximum]
   end
 
   def countable_text(value)

app/validators/poll_options_validator.rb

@@ -7,7 +7,7 @@ class PollOptionsValidator < ActiveModel::Validator
   def validate(poll)
     poll.errors.add(:options, I18n.t('polls.errors.too_few_options')) unless poll.options.size > 1
     poll.errors.add(:options, I18n.t('polls.errors.too_many_options', max: MAX_OPTIONS)) if poll.options.size > MAX_OPTIONS
-    poll.errors.add(:options, I18n.t('polls.errors.over_character_limit', max: MAX_OPTION_CHARS)) if poll.options.any? { |option| option.mb_chars.grapheme_length > MAX_OPTION_CHARS }
+    poll.errors.add(:options, I18n.t('polls.errors.over_character_limit', max: MAX_OPTION_CHARS)) if poll.options.any? { |option| option.length > MAX_OPTION_CHARS }
     poll.errors.add(:options, I18n.t('polls.errors.duplicate_options')) unless poll.options.uniq.size == poll.options.size
   end
 end

app/validators/status_length_validator.rb

@@ -18,7 +18,7 @@ class StatusLengthValidator < ActiveModel::Validator
   end
 
   def countable_length(str)
-    str.mb_chars.grapheme_length
+    str.length
   end
 
   def combined_text(status)