DAL.validators_method become a bound method, requires dal instance as first parameter

gluon/dal.py

@@ -4,7 +4,7 @@ from pydal import DAL as pyDAL
 from pydal import Field, SQLCustomType, geoPoint, geoLine, geoPolygon
 
 
-def _default_validators(field):
+def _default_validators(db, field):
     """
     Field type validation, using web2py's validators mechanism.
 
@@ -12,7 +12,6 @@ def _default_validators(field):
     fieldtype
     """
     from gluon import validators
-    db = field.db
     field_type, field_length = field.type, field.length
     requires = []
 

gluon/sqlhtml.py

@@ -1127,7 +1127,8 @@ class SQLFORM(FORM):
             extra_field.table = table
             extra_field.tablename = table._tablename
             if extra_field.requires == DEFAULT:
-                extra_field.requires = _default_validators(extra_field)
+                extra_field.requires = _default_validators(table._db,
+                                                           extra_field)
 
         for fieldname in self.fields:
             if fieldname.find('.') >= 0: