1 files changed, 40 insertions, 20 deletions
diff --git a/activesupport/lib/active_support/multibyte/unicode.rb b/activesupport/lib/active_support/multibyte/unicode.rb
index 4f0e1165ef..ce8ecece69 100644
--- a/activesupport/lib/active_support/multibyte/unicode.rb
+++ b/activesupport/lib/active_support/multibyte/unicode.rb
@@ -6,10 +6,17 @@ module ActiveSupport
       extend self
 
       # A list of all available normalization forms.
-      # See http://www.unicode.org/reports/tr15/tr15-29.html for more
+      # See https://www.unicode.org/reports/tr15/tr15-29.html for more
       # information about normalization.
       NORMALIZATION_FORMS = [:c, :kc, :d, :kd]
 
+      NORMALIZATION_FORM_ALIASES = { # :nodoc:
+        c: :nfc,
+        d: :nfd,
+        kc: :nfkc,
+        kd: :nfkd
+      }
+
       # The Unicode version that is supported by the implementation
       UNICODE_VERSION = RbConfig::CONFIG["UNICODE_VERSION"]
 
@@ -27,6 +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
 
@@ -34,6 +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
 
@@ -100,31 +117,34 @@ module ActiveSupport
       #   Default is ActiveSupport::Multibyte::Unicode.default_normalization_form.
       def normalize(string, form = nil)
         form ||= @default_normalization_form
-        # See http://www.unicode.org/reports/tr15, Table 1
-        case form
-        when :d
-          string.unicode_normalize(:nfd)
-        when :c
-          string.unicode_normalize(:nfc)
-        when :kd
-          string.unicode_normalize(:nfkd)
-        when :kc
-          string.unicode_normalize(:nfkc)
+
+        # See https://www.unicode.org/reports/tr15, Table 1
+        if alias_form = NORMALIZATION_FORM_ALIASES[form]
+          ActiveSupport::Deprecation.warn(<<-MSG.squish)
+            ActiveSupport::Multibyte::Unicode#normalize is deprecated and will be
+            removed from Rails 6.1. Use String#unicode_normalize(:#{alias_form}) instead.
+          MSG
+
+          string.unicode_normalize(alias_form)
         else
+          ActiveSupport::Deprecation.warn(<<-MSG.squish)
+            ActiveSupport::Multibyte::Unicode#normalize is deprecated and will be
+            removed from Rails 6.1. Use String#unicode_normalize instead.
+          MSG
+
           raise ArgumentError, "#{form} is not a valid normalization variant", caller
         end
       end
 
-      def downcase(string)
-        string.downcase
-      end
+      %w(downcase upcase swapcase).each do |method|
+        define_method(method) do |string|
+          ActiveSupport::Deprecation.warn(<<-MSG.squish)
+          ActiveSupport::Multibyte::Unicode##{method} is deprecated and
+          will be removed from Rails 6.1. Use String methods directly.
+          MSG
 
-      def upcase(string)
-        string.upcase
-      end
-
-      def swapcase(string)
-        string.swapcase
+          string.send(method)
+        end
       end
 
       private