2 files changed, 13 insertions, 15 deletions
diff --git a/activesupport/lib/active_support/multibyte/chars.rb b/activesupport/lib/active_support/multibyte/chars.rb
index 424ffa993c..a1e23aeaca 100644
--- a/activesupport/lib/active_support/multibyte/chars.rb
+++ b/activesupport/lib/active_support/multibyte/chars.rb
@@ -113,7 +113,7 @@ module ActiveSupport #:nodoc:
       #
       #   'Café'.mb_chars.reverse.to_s # => 'éfaC'
       def reverse
-        chars(Unicode.unpack_graphemes(@wrapped_string).reverse.flatten.pack("U*"))
+        chars(@wrapped_string.scan(/\X/).reverse.join)
       end
 
       # Limits the byte size of the string to a number of bytes without breaking
@@ -122,7 +122,7 @@ module ActiveSupport #:nodoc:
       #
       #   'こんにちは'.mb_chars.limit(7).to_s # => "こん"
       def limit(limit)
-        slice(0...translate_offset(limit))
+        truncate_bytes(limit, omission: nil)
       end
 
       # Capitalizes the first letter of every word, when possible.
@@ -183,7 +183,7 @@ module ActiveSupport #:nodoc:
       #   'क्षि'.mb_chars.length   # => 4
       #   'क्षि'.mb_chars.grapheme_length # => 3
       def grapheme_length
-        Unicode.unpack_graphemes(@wrapped_string).length
+        @wrapped_string.scan(/\X/).length
       end
 
       # Replaces all ISO-8859-1 or CP1252 characters by their UTF-8 equivalent
@@ -208,18 +208,6 @@ module ActiveSupport #:nodoc:
 
       private
 
-        def translate_offset(byte_offset)
-          return nil if byte_offset.nil?
-          return 0   if @wrapped_string == ""
-
-          begin
-            @wrapped_string.byteslice(0...byte_offset).unpack("U*").length
-          rescue ArgumentError
-            byte_offset -= 1
-            retry
-          end
-        end
-
         def chars(string)
           self.class.new(string)
         end
diff --git a/activesupport/lib/active_support/multibyte/unicode.rb b/activesupport/lib/active_support/multibyte/unicode.rb
index 43d196eeeb..ce8ecece69 100644
--- a/activesupport/lib/active_support/multibyte/unicode.rb
+++ b/activesupport/lib/active_support/multibyte/unicode.rb
@@ -34,6 +34,11 @@ module ActiveSupport
       #   Unicode.unpack_graphemes('क्षि') # => [[2325, 2381], [2359], [2367]]
       #   Unicode.unpack_graphemes('Café') # => [[67], [97], [102], [233]]
       def unpack_graphemes(string)
+        ActiveSupport::Deprecation.warn(<<-MSG.squish)
+          ActiveSupport::Multibyte::Unicode#unpack_graphemes is deprecated and will be
+          removed from Rails 6.1. Use string.scan(/\X/).map(&:codepoints) instead.
+        MSG
+
         string.scan(/\X/).map(&:codepoints)
       end
 
@@ -41,6 +46,11 @@ module ActiveSupport
       #
       #   Unicode.pack_graphemes(Unicode.unpack_graphemes('क्षि')) # => 'क्षि'
       def pack_graphemes(unpacked)
+        ActiveSupport::Deprecation.warn(<<-MSG.squish)
+          ActiveSupport::Multibyte::Unicode#pack_graphemes is deprecated and will be
+          removed from Rails 6.1. Use array.flatten.pack("U*") instead.
+        MSG
+
         unpacked.flatten.pack("U*")
       end