2 files changed, 41 insertions, 13 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb
index 8ccdd69b1d..e1a75f8e5e 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb
@@ -5,6 +5,8 @@ module ActiveRecord
         class Array < Type::Value # :nodoc:
           include Type::Helpers::Mutable
 
+          Data = Struct.new(:encoder, :values) # :nodoc:
+
           attr_reader :subtype, :delimiter
           delegate :type, :user_input_in_time_zone, :limit, :precision, :scale, to: :subtype
 
@@ -17,8 +19,11 @@ module ActiveRecord
           end
 
           def deserialize(value)
-            if value.is_a?(::String)
+            case value
+            when ::String
               type_cast_array(@pg_decoder.decode(value), :deserialize)
+            when Data
+              deserialize(value.values)
             else
               super
             end
@@ -33,11 +38,8 @@ module ActiveRecord
 
           def serialize(value)
             if value.is_a?(::Array)
-              result = @pg_encoder.encode(type_cast_array(value, :serialize))
-              if encoding = determine_encoding_of_strings(value)
-                result.force_encoding(encoding)
-              end
-              result
+              casted_values = type_cast_array(value, :serialize)
+              Data.new(@pg_encoder, casted_values)
             else
               super
             end
@@ -58,6 +60,10 @@ module ActiveRecord
             value.map(&block)
           end
 
+          def changed_in_place?(raw_old_value, new_value)
+            deserialize(raw_old_value) != new_value
+          end
+
           private
 
             def type_cast_array(value, method)
@@ -67,13 +73,6 @@ module ActiveRecord
                 @subtype.public_send(method, value)
               end
             end
-
-            def determine_encoding_of_strings(value)
-              case value
-              when ::Array then determine_encoding_of_strings(value.first)
-              when ::String then value.encoding
-              end
-            end
         end
       end
     end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb b/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb
index b5031d890f..3783925954 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb
@@ -92,6 +92,8 @@ module ActiveRecord
               else
                 super
               end
+            when OID::Array::Data
+              _quote(encode_array(value))
             else
               super
             end
@@ -106,10 +108,37 @@ module ActiveRecord
               { value: value.to_s, format: 1 }
             when OID::Xml::Data, OID::Bit::Data
               value.to_s
+            when OID::Array::Data
+              encode_array(value)
             else
               super
             end
           end
+
+          def encode_array(array_data)
+            encoder = array_data.encoder
+            values = type_cast_array(array_data.values)
+
+            result = encoder.encode(values)
+            if encoding = determine_encoding_of_strings_in_array(values)
+              result.force_encoding(encoding)
+            end
+            result
+          end
+
+          def determine_encoding_of_strings_in_array(value)
+            case value
+            when ::Array then determine_encoding_of_strings_in_array(value.first)
+            when ::String then value.encoding
+            end
+          end
+
+          def type_cast_array(values)
+            case values
+            when ::Array then values.map { |item| type_cast_array(item) }
+            else _type_cast(values)
+            end
+          end
       end
     end
   end