1 files changed, 10 insertions, 13 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
index d9b807bba4..571257f6dd 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
@@ -46,7 +46,7 @@ module ActiveRecord
         end
 
         # Create a new PostgreSQL database. Options include <tt>:owner</tt>, <tt>:template</tt>,
-        # <tt>:encoding</tt>, <tt>:collation</tt>, <tt>:ctype</tt>,
+        # <tt>:encoding</tt> (defaults to utf8), <tt>:collation</tt>, <tt>:ctype</tt>,
         # <tt>:tablespace</tt>, and <tt>:connection_limit</tt> (note that MySQL uses
         # <tt>:charset</tt> while PostgreSQL uses <tt>:encoding</tt>).
         #
@@ -172,7 +172,7 @@ module ActiveRecord
         def columns(table_name)
           # Limit, precision, and scale are all handled by the superclass.
           column_definitions(table_name).map do |column_name, type, default, notnull, oid, fmod|
-            oid = OID::TYPE_MAP.fetch(oid.to_i, fmod.to_i) {
+            oid = type_map.fetch(oid.to_i, fmod.to_i) {
               OID::Identity.new
             }
             PostgreSQLColumn.new(column_name, default, oid, type, notnull == 'f')
@@ -321,6 +321,7 @@ module ActiveRecord
             result = query(<<-end_sql, 'SCHEMA')[0]
               SELECT attr.attname,
                 CASE
+                  WHEN pg_get_expr(def.adbin, def.adrelid) !~* 'nextval' THEN NULL
                   WHEN split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2) ~ '.' THEN
                     substr(split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2),
                            strpos(split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2), '.')+1)
@@ -332,7 +333,7 @@ module ActiveRecord
               JOIN pg_constraint  cons ON (conrelid = adrelid AND adnum = conkey[1])
               WHERE t.oid = '#{quote_table_name(table)}'::regclass
                 AND cons.contype = 'p'
-                AND pg_get_expr(def.adbin, def.adrelid) ~* 'nextval'
+                AND pg_get_expr(def.adbin, def.adrelid) ~* 'nextval|uuid_generate'
             end_sql
           end
 
@@ -383,8 +384,9 @@ module ActiveRecord
         def change_column(table_name, column_name, type, options = {})
           clear_cache!
           quoted_table_name = quote_table_name(table_name)
-
-          execute "ALTER TABLE #{quoted_table_name} ALTER COLUMN #{quote_column_name(column_name)} TYPE #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
+          sql_type = type_to_sql(type, options[:limit], options[:precision], options[:scale])
+          sql_type << "[]" if options[:array]
+          execute "ALTER TABLE #{quoted_table_name} ALTER COLUMN #{quote_column_name(column_name)} TYPE #{sql_type}"
 
           change_column_default(table_name, column_name, options[:default]) if options_include_default?(options)
           change_column_null(table_name, column_name, options[:null], options[:default]) if options.key?(:null)
@@ -466,22 +468,17 @@ module ActiveRecord
           end
         end
 
-        # Returns a SELECT DISTINCT clause for a given set of columns and a given ORDER BY clause.
-        #
         # PostgreSQL requires the ORDER BY columns in the select list for distinct queries, and
         # requires that the ORDER BY include the distinct column.
-        #
-        #   distinct("posts.id", ["posts.created_at desc"])
-        #   # => "DISTINCT posts.id, posts.created_at AS alias_0"
-        def distinct(columns, orders) #:nodoc:
-          order_columns = orders.map{ |s|
+        def columns_for_distinct(columns, orders) #:nodoc:
+          order_columns = orders.reject(&:blank?).map{ |s|
               # Convert Arel node to string
               s = s.to_sql unless s.is_a?(String)
               # Remove any ASC/DESC modifiers
               s.gsub(/\s+(ASC|DESC)\s*(NULLS\s+(FIRST|LAST)\s*)?/i, '')
             }.reject(&:blank?).map.with_index { |column, i| "#{column} AS alias_#{i}" }
 
-          [super].concat(order_columns).join(', ')
+          [super, *order_columns].join(', ')
         end
       end
     end