Use YAML.load_tags/dump_tags to prevent deprecation warnings

The default behavior of the Psych gem for Ruby classes is to call the
`name` method to generate a tag for encoding. However this causes a
stream of deprecation warnings whenever ActiveSupport::TimeWithZone
instances are encoded into YAML. By utilising the load_tags/dump_tags
configuration we can prevent Psych from calling the `name` method and
thereby prevent the triggering of the deprecation warnings.

activesupport/lib/active_support/time_with_zone.rb

@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require "yaml"
+
 require "active_support/duration"
 require "active_support/values/time_zone"
 require "active_support/core_ext/object/acts_like"
@@ -182,7 +184,6 @@ module ActiveSupport
     end
 
     def encode_with(coder) #:nodoc:
-      coder.tag = "!ruby/object:ActiveSupport::TimeWithZone"
       coder.map = { "utc" => utc, "zone" => time_zone, "time" => time }
     end
 
@@ -588,3 +589,8 @@ module ActiveSupport
       end
   end
 end
+
+# These prevent Psych from calling `ActiveSupport::TimeWithZone.name`
+# and triggering the deprecation warning about the change in Rails 7.1.
+YAML.load_tags["!ruby/object:ActiveSupport::TimeWithZone"] = "ActiveSupport::TimeWithZone"
+YAML.dump_tags[ActiveSupport::TimeWithZone] = "!ruby/object:ActiveSupport::TimeWithZone"

activesupport/test/core_ext/hash_ext_test.rb

@@ -585,6 +585,7 @@ class HashToXmlTest < ActiveSupport::TestCase
   end
 
   def test_timezoned_attributes
+    # TODO: Remove assertion in Rails 7.1 and add ActiveSupport::TimeWithZone to XML type mapping
     assert_deprecated("ActiveSupport::TimeWithZone.name has been deprecated") do
       xml = {
         created_at: Time.utc(1999, 2, 2),

activesupport/test/core_ext/time_with_zone_test.rb

@@ -186,7 +186,8 @@ class TimeWithZoneTest < ActiveSupport::TestCase
       time: 1999-12-31 19:00:00.000000000 Z
     EOF
 
-    assert_deprecated("ActiveSupport::TimeWithZone.name has been deprecated") do
+    # TODO: Remove assertion in Rails 7.1
+    assert_not_deprecated do
       assert_equal(yaml, @twz.to_yaml)
     end
   end
@@ -201,7 +202,8 @@ class TimeWithZoneTest < ActiveSupport::TestCase
         time: 1999-12-31 19:00:00.000000000 Z
     EOF
 
-    assert_deprecated("ActiveSupport::TimeWithZone.name has been deprecated") do
+    # TODO: Remove assertion in Rails 7.1
+    assert_not_deprecated do
       assert_equal(yaml, { "twz" => @twz }.to_yaml)
     end
   end
@@ -571,6 +573,7 @@ class TimeWithZoneTest < ActiveSupport::TestCase
   end
 
   def test_class_name
+    # TODO: Remove assertion in Rails 7.1 and change expected value
     assert_deprecated("ActiveSupport::TimeWithZone.name has been deprecated") do
       assert_equal "Time", ActiveSupport::TimeWithZone.name
     end