Move array database type casting to the Array type

The case where we have a column object, but don't have a type cast
method involves type casting the default value when changing the schema.
We get one of the column definition structs instead. That is a case that
I'm trying to remove overall, but in the short term, we can achieve the
same behavior without needing to pass the adapter to the array type by
creating a fake type that proxies to the adapter.

4 files changed, 62 insertions, 38 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/cast.rb b/activerecord/lib/active_record/connection_adapters/postgresql/cast.rb
index bb54de05c8..6042ab9225 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/cast.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/cast.rb
@@ -38,21 +38,6 @@ module ActiveRecord
           end
         end
 
-        def array_to_string(value, column, adapter) # :nodoc:
-          casted_values = value.map do |val|
-            if String === val
-              if val == "NULL"
-                "\"#{val}\""
-              else
-                quote_and_escape(adapter.type_cast(val, column, true))
-              end
-            else
-              adapter.type_cast(val, column, true)
-            end
-          end
-          "{#{casted_values.join(',')}}"
-        end
-
         def range_to_string(object) # :nodoc:
           from = object.begin.respond_to?(:infinite?) && object.begin.infinite? ? '' : object.begin
           to   = object.end.respond_to?(:infinite?) && object.end.infinite? ? '' : object.end
@@ -86,19 +71,6 @@ module ActiveRecord
               end
             end
           end
-
-          ARRAY_ESCAPE = "\\" * 2 * 2 # escape the backslash twice for PG arrays
-
-          def quote_and_escape(value)
-            case value
-            when "NULL", Numeric
-              value
-            else
-              value = value.gsub(/\\/, ARRAY_ESCAPE)
-              value.gsub!(/"/,"\\\"")
-              "\"#{value}\""
-            end
-          end
       end
     end
   end
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 4e7d472d97..b686e1e5ad 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb
@@ -22,6 +22,14 @@ module ActiveRecord
             type_cast_array(value, :type_cast_from_user)
           end
 
+          def type_cast_for_database(value)
+            if value.is_a?(::Array)
+              cast_value_for_database(value)
+            else
+              super
+            end
+          end
+
           # Loads pg_array_parser if available. String parsing can be
           # performed quicker by a native extension, which will not create
           # a large amount of Ruby objects that will need to be garbage
@@ -43,6 +51,28 @@ module ActiveRecord
               @subtype.public_send(method, value)
             end
           end
+
+          def cast_value_for_database(value)
+            if value.is_a?(::Array)
+              casted_values = value.map { |item| cast_value_for_database(item) }
+              "{#{casted_values.join(',')}}"
+            else
+              quote_and_escape(subtype.type_cast_for_database(value))
+            end
+          end
+
+          ARRAY_ESCAPE = "\\" * 2 * 2 # escape the backslash twice for PG arrays
+
+          def quote_and_escape(value)
+            case value
+            when ::String
+              value = value.gsub(/\\/, ARRAY_ESCAPE)
+              value.gsub!(/"/,"\\\"")
+              %("#{value}")
+            when nil then "NULL"
+            else value
+            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 3cf40e6cd4..17fabe5af6 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb
@@ -32,11 +32,7 @@ module ActiveRecord
             when 'point' then super(PostgreSQLColumn.point_to_string(value))
             when 'json' then super(PostgreSQLColumn.json_to_string(value))
             else
-              if column.array
-                "'#{PostgreSQLColumn.array_to_string(value, column, self).gsub(/'/, "''")}'"
-              else
-                super
-              end
+              super(value, array_column(column))
             end
           when Hash
             case sql_type
@@ -98,11 +94,7 @@ module ActiveRecord
             when 'point' then PostgreSQLColumn.point_to_string(value)
             when 'json' then PostgreSQLColumn.json_to_string(value)
             else
-              if column.array
-                PostgreSQLColumn.array_to_string(value, column, self)
-              else
-                super(value, column)
-              end
+              super(value, array_column(column))
             end
           when Hash
             case column.sql_type
@@ -185,6 +177,26 @@ module ActiveRecord
             super
           end
         end
+
+        def array_column(column)
+          if column.array && !column.respond_to?(:type_cast_for_database)
+            OID::Array.new(AdapterProxyType.new(column, self))
+          else
+            column
+          end
+        end
+
+        class AdapterProxyType < SimpleDelegator
+          def initialize(column, adapter)
+            @column = column
+            @adapter = adapter
+            super(column)
+          end
+
+          def type_cast_for_database(value)
+            @adapter.type_cast(value, @column)
+          end
+        end
       end
     end
   end
diff --git a/activerecord/lib/active_record/type/date_time.rb b/activerecord/lib/active_record/type/date_time.rb
index 560d63c101..5f19608a33 100644
--- a/activerecord/lib/active_record/type/date_time.rb
+++ b/activerecord/lib/active_record/type/date_time.rb
@@ -7,6 +7,16 @@ module ActiveRecord
         :datetime
       end
 
+      def type_cast_for_database(value)
+        zone_conversion_method = ActiveRecord::Base.default_timezone == :utc ? :getutc : :getlocal
+
+        if value.acts_like?(:time)
+          value.send(zone_conversion_method)
+        else
+          super
+        end
+      end
+
       private
 
       def cast_value(string)