1 files changed, 24 insertions, 8 deletions
diff --git a/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb b/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
index 9e693b6aee..ebaaa54b2b 100644
--- a/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
+++ b/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
@@ -1,3 +1,5 @@
+require 'active_support/core_ext/string/strip'
+
 module ActiveRecord
   module AttributeMethods
     module TimeZoneConversion
@@ -7,9 +9,9 @@ module ActiveRecord
         end
 
         def cast(value)
-          if value.is_a?(Array)
-            value.map { |v| cast(v) }
-          elsif value.is_a?(Hash)
+          return if value.nil?
+
+          if value.is_a?(Hash)
             set_time_zone_without_conversion(super)
           elsif value.respond_to?(:in_time_zone)
             begin
@@ -17,24 +19,38 @@ module ActiveRecord
             rescue ArgumentError
               nil
             end
+          else
+            map_avoiding_infinite_recursion(super) { |v| cast(v) }
           end
         end
 
         private
 
         def convert_time_to_time_zone(value)
-          if value.is_a?(Array)
-            value.map { |v| convert_time_to_time_zone(v) }
-          elsif value.acts_like?(:time)
+          return if value.nil?
+
+          if value.acts_like?(:time)
             value.in_time_zone
-          else
+          elsif value.is_a?(::Float)
             value
+          else
+            map_avoiding_infinite_recursion(value) { |v| convert_time_to_time_zone(v) }
           end
         end
 
         def set_time_zone_without_conversion(value)
           ::Time.zone.local_to_utc(value).in_time_zone
         end
+
+        def map_avoiding_infinite_recursion(value)
+          map(value) do |v|
+            if value.equal?(v)
+              nil
+            else
+              yield(v)
+            end
+          end
+        end
       end
 
       extend ActiveSupport::Concern
@@ -77,7 +93,7 @@ module ActiveRecord
             !result &&
             cast_type.type == :time &&
             time_zone_aware_types.include?(:not_explicitly_configured)
-            ActiveSupport::Deprecation.warn(<<-MESSAGE)
+            ActiveSupport::Deprecation.warn(<<-MESSAGE.strip_heredoc)
               Time columns will become time zone aware in Rails 5.1. This
               still causes `String`s to be parsed as if they were in `Time.zone`,
               and `Time`s to be converted to `Time.zone`.