1 files changed, 26 insertions, 16 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/hstore.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/hstore.rb
index 9270fc9f21..49dd4fc73f 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/hstore.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/hstore.rb
@@ -12,8 +12,8 @@ module ActiveRecord
           def deserialize(value)
             if value.is_a?(::String)
               ::Hash[value.scan(HstorePair).map { |k, v|
-                v = v.upcase == 'NULL' ? nil : v.gsub(/\A"(.*)"\Z/m,'\1').gsub(/\\(.)/, '\1')
-                k = k.gsub(/\A"(.*)"\Z/m,'\1').gsub(/\\(.)/, '\1')
+                v = v.upcase == "NULL" ? nil : v.gsub(/\A"(.*)"\Z/m, '\1').gsub(/\\(.)/, '\1')
+                k = k.gsub(/\A"(.*)"\Z/m, '\1').gsub(/\\(.)/, '\1')
                 [k, v]
               }]
             else
@@ -23,7 +23,9 @@ module ActiveRecord
 
           def serialize(value)
             if value.is_a?(::Hash)
-              value.map { |k, v| "#{escape_hstore(k)}=>#{escape_hstore(v)}" }.join(', ')
+              value.map { |k, v| "#{escape_hstore(k)}=>#{escape_hstore(v)}" }.join(", ")
+            elsif value.respond_to?(:to_unsafe_h)
+              serialize(value.to_unsafe_h)
             else
               value
             end
@@ -33,25 +35,33 @@ module ActiveRecord
             ActiveRecord::Store::StringKeyedHashAccessor
           end
 
+          # Will compare the Hash equivalents of +raw_old_value+ and +new_value+.
+          # By comparing hashes, this avoids an edge case where the order of
+          # the keys change between the two hashes, and they would not be marked
+          # as equal.
+          def changed_in_place?(raw_old_value, new_value)
+            deserialize(raw_old_value) != new_value
+          end
+
           private
 
-          HstorePair = begin
-            quoted_string = /"[^"\\]*(?:\\.[^"\\]*)*"/
-            unquoted_string = /(?:\\.|[^\s,])[^\s=,\\]*(?:\\.[^\s=,\\]*|=[^,>])*/
-            /(#{quoted_string}|#{unquoted_string})\s*=>\s*(#{quoted_string}|#{unquoted_string})/
-          end
+            HstorePair = begin
+              quoted_string = /"[^"\\]*(?:\\.[^"\\]*)*"/
+              unquoted_string = /(?:\\.|[^\s,])[^\s=,\\]*(?:\\.[^\s=,\\]*|=[^,>])*/
+              /(#{quoted_string}|#{unquoted_string})\s*=>\s*(#{quoted_string}|#{unquoted_string})/
+            end
 
-          def escape_hstore(value)
-            if value.nil?
-              'NULL'
-            else
-              if value == ""
-                '""'
+            def escape_hstore(value)
+              if value.nil?
+                "NULL"
               else
-                '"%s"' % value.to_s.gsub(/(["\\])/, '\\\\\1')
+                if value == ""
+                  '""'
+                else
+                  '"%s"' % value.to_s.gsub(/(["\\])/, '\\\\\1')
+                end
               end
             end
-          end
         end
       end
     end