XSD 1.1: Nested all inside group treats optional elements as required #437
Description
xmlschema 3.4.3, python 3.12, macOS Sonoma 14.7.4:
Something has changed in the XSD 1.1 interpretation of xs:group containing xs:all with only optional elements. The intent is that none of the elements in the xs:all group is required. However, in this version of xmlschema, a reference to the xs:group will only validate if at least one element in the xs:all is present.
A sample schema:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE xs:schema PUBLIC "-//W3C//DTD XSD 1.1//EN" "http://www.w3.org/2009/XMLSchema/XMLSchema.dtd" >
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:xml="http://www.w3.org/XML/1998/namespace"
xml:lang="en">
<xs:attribute name="NodeType">
<xs:simpleType>
<xs:restriction base="xs:NMTOKEN">
<xs:enumeration value="NodeList"/>
<xs:enumeration value="Empty"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:element name="Comment" type="xs:string"/>
<!-- These are elements which may be omitted from a valid Node -->
<xs:group name="ActionOptions">
<xs:all>
<xs:element ref="Comment" minOccurs="0"/>
</xs:all>
</xs:group>
<xs:element name="NodeId">
<xs:complexType>
<xs:simpleContent>
<xs:extension base="xs:NCName">
<xs:attribute name="generated" type="xs:boolean" />
</xs:extension>
</xs:simpleContent>
</xs:complexType>
</xs:element>
<xs:element name="NodeList">
<xs:complexType>
<xs:sequence>
<xs:group ref="ActionGroup" minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:element name="NodeBody">
<xs:complexType>
<xs:choice>
<xs:element ref="NodeList"/>
</xs:choice>
</xs:complexType>
</xs:element>
<xs:complexType name="NodeActionType">
<xs:all>
<xs:group ref="ActionOptions"/>
<xs:element ref="NodeId"/>
<xs:element ref="NodeBody" minOccurs="0"/>
</xs:all>
<xs:attribute ref="NodeType" use="required"/>
</xs:complexType>
<xs:element name="Node" type="NodeActionType" />
<xs:group name="ActionGroup">
<xs:choice>
<xs:element ref="Node"/>
</xs:choice>
</xs:group>
<xs:element name="PlexilPlan">
<xs:complexType>
<xs:sequence>
<xs:group ref="ActionGroup"/>
</xs:sequence>
<!-- Attempt to imitate rncfix -->
<xs:anyAttribute namespace="http://www.w3.org/2001/XMLSchema-instance"
processContents="skip"/>
</xs:complexType>
</xs:element>
</xs:schema>
This content validates:
<?xml version="1.0" encoding="utf-8"?>
<PlexilPlan xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<Node NodeType="Empty">
<Comment> This is a comment. </Comment>
<NodeId>One</NodeId>
</Node>
</PlexilPlan>
This content fails to validate:
<?xml version="1.0" encoding="utf-8"?>
<PlexilPlan xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<Node NodeType="Empty">
<NodeId>One</NodeId>
</Node>
</PlexilPlan>