you can provide uuid_generate_v4 as the default value for uuid columns

3 files changed, 52 insertions, 2 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
index 805832f01e..21dda17f2f 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
@@ -29,6 +29,7 @@ module ActiveRecord
         column_options = {}
         column_options[:null] = null unless null.nil?
         column_options[:default] = default unless default.nil?
+        column_options[:column] = self
         add_column_options!(column_sql, column_options) unless type.to_sym == :primary_key
         column_sql
       end
@@ -36,7 +37,7 @@ module ActiveRecord
       private
 
         def add_column_options!(sql, options)
-          base.add_column_options!(sql, options.merge(:column => self))
+          base.add_column_options!(sql, options)
         end
     end
 
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index eb541b0215..dfa4c3967a 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -632,7 +632,13 @@ module ActiveRecord
         if options[:array] || options[:column].try(:array)
           sql << '[]'
         end
-        super
+
+        column = options.fetch(:column) { return super }
+        if column.type == :uuid && options[:default] =~ /\(\)/
+          sql << " DEFAULT #{options[:default]}"
+        else
+          super
+        end
       end
 
       # Set the authorized user for this session
diff --git a/activerecord/test/cases/adapters/postgresql/uuid_test.rb b/activerecord/test/cases/adapters/postgresql/uuid_test.rb
new file mode 100644
index 0000000000..53002c5265
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/uuid_test.rb
@@ -0,0 +1,43 @@
+# encoding: utf-8
+
+require "cases/helper"
+require 'active_record/base'
+require 'active_record/connection_adapters/postgresql_adapter'
+
+class PostgresqlUUIDTest < ActiveRecord::TestCase
+  class UUID < ActiveRecord::Base
+    self.table_name = 'pg_uuids'
+  end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+
+    unless @connection.supports_extensions?
+      return skip "do not test on PG without uuid-ossp"
+    end
+
+    unless @connection.extension_enabled?('uuid-ossp')
+      @connection.enable_extension 'uuid-ossp'
+      @connection.commit_db_transaction
+    end
+
+    @connection.reconnect!
+
+    @connection.transaction do
+      @connection.create_table('pg_uuids', id: :uuid) do |t|
+        t.string 'name'
+        t.uuid 'other_uuid', default: 'uuid_generate_v4()'
+      end
+    end
+  end
+
+  def teardown
+    @connection.execute 'drop table if exists pg_uuids'
+  end
+
+  def test_auto_create_uuid
+    u = UUID.create
+    u.reload
+    assert_not_nil u.other_uuid
+  end
+end