2233 2005-09-14 19:34:45 +0000 R-241: Question re: Validation of an element restriction whose base type has the variety union 2009-04-21 19:21:38 +0000 1 1 1 Unclassified XML Schema Structures: XSD Part 1 1.1 only All All CLOSED FIXED resolved P4 normal --- 1 sandygao cmsmcq www-xml-schema-comments oldest_to_newest 6260 0 sandygao 2005-09-14 19:34:45 +0000 It seems to me that the the following schema should be invalid because the value space of the base type definition of the element "e" in the type "ct- base" is not a super set of the value space of the base type definition of the element "e" in "ct-deriv"; but I cannot find any Schema Component Constraint invalidating it. <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"> <xs:simpleType name="base"> <xs:union memberTypes="xs:boolean xs:integer"/> </xs:simpleType> <xs:simpleType name="deriv"> <xs:restriction base="base"> <xs:enumeration value="1"/> <xs:enumeration value="2"/> </xs:restriction> </xs:simpleType> <xs:complexType name="ct-base"> <xs:sequence> <xs:element name="e" type="deriv"/> </xs:sequence> </xs:complexType> <xs:complexType name="ct-deriv"> <xs:complexContent> <xs:restriction base="ct-base"> <xs:sequence> <xs:element name="e" type="xs:integer"/> </xs:sequence> </xs:restriction> </xs:complexContent> </xs:complexType> </xs:schema> Using cos-st-derived-ok [1], xs:integer seems to be validly derived given {extension, list, union} from deriv (because the member type definitions property of deriv is the the member type definitions of base). Therefore, rcase_NameAntTypeOK [2] is not violated, and the restriction seems to be valid. Comment originally posted to xmlschema-dev mail list. 6261 1 sandygao 2005-09-14 19:34:54 +0000 See: http://lists.w3.org/Archives/Public/www-xml-schema-comments/2003OctDec/0038.html 11983 2 cmsmcq 2006-09-23 22:46:52 +0000 The problem identified here is the same as the one mentioned in bug 2333; it has been addressed in XML Schema 1.1 by eliminating the practice of 'flattening' union, thus ensuring that when a union is restricted, its union-level facets are not lost when it is named as a member of another union. The same change addresses the problem identified here, in which the union-level facets are lost when restriction is checked. Under the new rules, the restriction of ct-base by ct-deriv is not legal, since the type assigned to element e in ct-deriv is not a restriction of the type assigned to that element in ct-base. The original comment still applies to XML Schema 1.0, and I have made a separate issue for 1.0 (bug 3763). With the change to the treatment of unions, which is reflected in the current published working draft, I believe this issue has been resolved, so I am changing its status to RESOLVED / FIXED. 11984 3 cmsmcq 2006-09-23 23:09:23 +0000 For the record: a response has been sent to Michael Marchegay, who originally raised this issue (on xmlschema-dev) and to Alessandro Triglia, who seconded the point and forwarded the mail to the schema comments list. A copy of the response may be found in the archive of the XML Schema comments list http://lists.w3.org/Archives/Public/www-xml-schema-comments/2006JulSep/0157.html