--- a/ChangeLog	Fri Oct 28 11:55:18 2011 +0200
+++ b/ChangeLog	Wed Nov 09 18:17:37 2011 +0100
@@ -7,7 +7,7 @@
     * #80799: fix wrong type analysis with 'NOT identity'
     * when possible, use entity type as translation context of relation
       (break cw < 3.13.10 compat)
-
+    * #81817: fix add_type_restriction for cases where some types restriction is already in there
 
 2011-09-07  --  0.30.1
 

--- a/nodes.py	Fri Oct 28 11:55:18 2011 +0200
+++ b/nodes.py	Wed Nov 09 18:17:37 2011 +0100
@@ -30,7 +30,7 @@
 
 from logilab.database import DYNAMIC_RTYPE
 
-from rql import CoercionError
+from rql import CoercionError, RQLException
 from rql.base import BaseNode, Node, BinaryNode, LeafNode
 from rql.utils import (function_description, quote, uquote, build_visitor_stub,
                        common_parent)
@@ -218,6 +218,39 @@
 
     def add_type_restriction(self, var, etype):
         """builds a restriction node to express : variable is etype"""
+        typerel = var.stinfo.get('typerel', None)
+        if typerel:
+            istarget = typerel.children[1].children[0]
+            if typerel.r_type == 'is':
+                if isinstance(istarget, Constant):
+                    etypes = (istarget.value,)
+                else: # Function (IN)
+                    etypes = [et.value for et in istarget.children]
+                if etype not in etypes:
+                    raise RQLException('%r not in %r' % (etype, etypes))
+                if len(etypes) > 1:
+                    for child in istarget.children:
+                        if child.value != etype:
+                            istarget.remove(child)
+            else:
+                # let's botte en touche IN cases (who would do that anyway ?)
+                if isinstance(istarget, Function):
+                    msg = 'adding type restriction over is_instance_of IN is not supported'
+                    raise NotImplementedError(msg)
+                schema = self.root.schema
+                if schema is None:
+                    msg = 'restriction with is_instance_of cannot be done without a schema'
+                    raise RQLException(msg)
+                # let's check the restriction is compatible
+                eschema = schema[etype]
+                ancestors = set(eschema.ancestors())
+                ancestors.add(etype) # let's be unstrict
+                if istarget.value in ancestors:
+                    istarget.value = etype
+                else:
+                    raise RQLException('type restriction %s-%s cannot be made on %s' %
+                                       (var, etype, self))
+            return typerel
         return self.add_constant_restriction(var, 'is', etype, 'etype')
 
 

--- a/test/unittest_nodes.py	Fri Oct 28 11:55:18 2011 +0200
+++ b/test/unittest_nodes.py	Wed Nov 09 18:17:37 2011 +0100
@@ -21,7 +21,7 @@
 
 from logilab.common.testlib import TestCase, unittest_main
 
-from rql import nodes, stmts, parse, BadRQLQuery, RQLHelper
+from rql import nodes, stmts, parse, BadRQLQuery, RQLHelper, RQLException
 
 from unittest_analyze import DummySchema
 schema = DummySchema()
@@ -55,6 +55,43 @@
         self.assertEqual(nodes.etype_from_pyobj(u'hop'), 'String')
 
 
+class TypesRestrictionNodesTest(TestCase):
+
+    def setUp(self):
+        self.parse = helper.parse
+        self.simplify = helper.simplify
+
+    def test_add_is_type_restriction(self):
+        tree = self.parse('Any X WHERE X is Person')
+        select = tree.children[0]
+        x = select.get_selected_variables().next()
+        self.assertRaises(RQLException, select.add_type_restriction, x.variable, 'Babar')
+        select.add_type_restriction(x.variable, 'Person')
+        self.assertEqual(tree.as_string(), 'Any X WHERE X is Person')
+
+    def test_add_new_is_type_restriction_in(self):
+        tree = self.parse('Any X WHERE X is IN(Person, Company)')
+        select = tree.children[0]
+        x = select.get_selected_variables().next()
+        select.add_type_restriction(x.variable, 'Company')
+        # implementation is KISS (the IN remains)
+        self.assertEqual(tree.as_string(), 'Any X WHERE X is IN(Company)')
+
+    def test_add_is_in_type_restriction(self):
+        tree = self.parse('Any X WHERE X is IN(Person, Company)')
+        select = tree.children[0]
+        x = select.get_selected_variables().next()
+        self.assertRaises(RQLException, select.add_type_restriction, x.variable, 'Babar')
+        self.assertEqual(tree.as_string(), 'Any X WHERE X is IN(Person, Company)')
+
+    # XXX a full schema is needed, see test in cw/server/test/unittest_security
+    # def test_add_is_against_isintance_type_restriction(self):
+    #     tree = self.parse('Any X WHERE X is_instance_of Person')
+    #     select = tree.children[0]
+    #     x = select.get_selected_variables().next()
+    #     select.add_type_restriction(x.variable, 'Student')
+    #     self.parse(tree.as_string())
+
 class NodesTest(TestCase):
     def _parse(self, rql, normrql=None):
         tree = parse(rql + ';')