Uniqueness constraint issue when deriving via restriction using substitution
groups.
------------------------------------------------------------------------------------
Key: XERCESC-1905
URL: https://issues.apache.org/jira/browse/XERCESC-1905
Project: Xerces-C++
Issue Type: Bug
Components: Validating Parser (XML Schema)
Affects Versions: 3.0.1
Environment: x86_64-windows-vc-9.0
Reporter: Jack Gager
The schema compilation reports the error with the following schema:
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema targetNamespace="test" elementFormDefault="qualified"
xmlns:xs="http://www.w3.org/2001/XMLSchema"; xmlns="test">
<xs:element name="SubHead" type="SubHeadType">
<xs:unique name="SubHeadUnique">
<xs:selector xpath="*"/>
<xs:field xpath="@ID"/>
</xs:unique>
</xs:element>
<xs:complexType name="SubHeadType">
<xs:sequence>
<xs:element name="Child" type="ChildType"
maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
<xs:complexType name="ChildType">
<xs:simpleContent>
<xs:extension base="xs:string">
<xs:attribute name="ID" type="xs:string"/>
</xs:extension>
</xs:simpleContent>
</xs:complexType>
<xs:element name="Sub" type="SubType" substitutionGroup="SubHead">
<xs:unique name="RUnique">
<xs:selector xpath="*"/>
<xs:field xpath="@ID"/>
</xs:unique>
</xs:element>
<xs:complexType name="SubType">
<xs:complexContent>
<xs:extension base="SubHeadType">
<xs:attribute name="id" type="xs:string"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
<xs:element name="BFail" type="BFailType"/>
<xs:complexType name="BFailType">
<xs:sequence>
<xs:element ref="SubHead"/>
</xs:sequence>
</xs:complexType>
<xs:element name="R" type="RFailType"/>
<xs:complexType name="RFailType">
<xs:complexContent>
<xs:restriction base="BFailType">
<xs:sequence>
<xs:element ref="Sub"/>
</xs:sequence>
</xs:restriction>
</xs:complexContent>
</xs:complexType>
<xs:element name="Sub2" type="SubType"/>
<xs:element name="BPass" type="BPassType"/>
<xs:complexType name="BPassType">
<xs:choice>
<xs:element ref="Sub2"/>
<xs:element ref="Sub"/>
</xs:choice>
</xs:complexType>
<xs:element name="RPass" type="RPassType"/>
<xs:complexType name="RPassType">
<xs:complexContent>
<xs:restriction base="BPassType">
<xs:sequence>
<xs:element ref="Sub"/>
</xs:sequence>
</xs:restriction>
</xs:complexContent>
</xs:complexType>
</xs:schema>
The error reported is:
"<file>, line 50, char 35
Message: element 'Sub' has identity constraint that does not appear in
corresponding element 'SubHead' in the base
Did not parse a schema document cleanly so not printing Schema for Schema
XSModel information"
If the uniqueness constraint on the Sub element is removed the schema is
compiled successfully.
According to the XML Schema specification, the head of a substitution group is
to be treated as a choice between all of the members of that substitution
group. Therefore the particle derivation validation for the RFailType boils
down to whether
<xs:sequence>
<xs:element ref="Sub"/>
</xs:sequence>
is a valid restriction of
<xs:choice>
<xs:element ref="SubHead"/>
<xs:element ref="Sub"/>
</xs:choice>
According to the MapAndSum for a sequence particle derived from a choice
particle, 2 conditions must be met:
"1 There is a complete functional mapping from the particles in the {particles}
of R to the particles in the {particles} of B such that each particle in the
{particles} of R is a - valid restriction- of the particle in the {particles}
of B it maps to as defined by Particle Valid (Restriction) (§3.9.6).
2 The pair consisting of the product of the {min occurs} of R and the length of
its {particles} and unbounded if {max occurs} is unbounded otherwise the
product of the {max occurs} of R and the length of its {particles} is a valid
restriction of B's occurrence range as defined by Occurrence Range OK (§3.9.6)."
These are both met - however the schema compilation is reporting that condition
1 is not met. The XML Schema specification rules for determining the individual
element's validity are as follows:
"For an element declaration particle to be a - valid restriction- of another
element declaration particle all of the following must be true:
1 The declarations' {name}s and {target namespace}s are the same.
2 R's occurrence range is a valid restriction of B's occurrence range as
defined by Occurrence Range OK (§3.9.6).
3 One of the following must be true:
3.1 Both B's declaration's {scope} and R's declaration's {scope} are global.
3.2 All of the following must be true:
3.2.1 Either B's {nillable} is true or R's {nillable} is false.
3.2.2 either B's declaration's {value constraint} is absent, or is not
fixed, or R's declaration's {value constraint} is fixed with the same value.
3.2.3 R's declaration's {identity-constraint definitions} is a subset of
B's declaration's {identity-constraint definitions}, if any.
3.2.4 R's declaration's {disallowed substitutions} is a superset of B's
declaration's {disallowed substitutions}.
3.2.5 R's {type definition} is validly derived given {extension, list,
union} from B's {type definition} as defined by Type Derivation OK (Complex)
(§3.4.6) or Type Derivation OK (Simple) (§3.14.6), as appropriate."
Since the element in the derived sequence particle is the same as the element
in the base choice particle, and they are both global - the element declaration
is a valid restriction.
This can be seen to be implemented correctly when dealing with a choice
directly (as opposed to one derived from a substitution head) in the example
where RPass derives from BPass. These types are compiled without issues. It
would seem as though the choice created from the substitution head does not
include the uniqueness constraints from the members global element definitions.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
