Inherit default qualification from schema when not specified

[veewee]

Both attributes and elements have a default qualification of false.
The reader does not take into account the schema configurations attributeFormDefault and elementFormDefault.

This PR introduces a fallback to the schema settings if the form attribute does not exist.

<xs:schema version="1.0" targetNamespace="http://www.example.com"
    xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified">
    <xs:complexType name="root">
        <xs:sequence>
            <xs:element name="item1" type="xs:string" form="qualified" />
            <xs:element name="item2" type="xs:string" form="unqualified" />
            <xs:element name="item3" type="xs:string" />
        </xs:sequence>
    </xs:complexType>
</xs:schema>

<xs:schema version="1.0" targetNamespace="http://www.example.com"
    xmlns:xs="http://www.w3.org/2001/XMLSchema" attributeFormDefault="qualified">
    <xs:complexType name="root">
        <xs:attribute name="item1" type="xs:int" form="qualified"/>
        <xs:attribute name="item2" type="xs:int" form="unqualified"/>
        <xs:attribute name="item3" type="xs:int"/>
    </xs:complexType>
</xs:schema>

[goetas]

Is this a standard thing? is it mentioned in any doc?

[veewee]

Yes it is.

The form on element / attribute can have 3 states:

• qualified : display with namespace prefix
• unqualified : display as local name
• not set : This now falls back to false in this package, however it should fall back to the defaults configured at schema level. (elementFormDefault or attributeFormDefault - in case these are not set, it should default to false)

See the offical spec:

https://www.w3.org/TR/xmlschema11-1/

<schema
  attributeFormDefault = (qualified | unqualified) : unqualified
  elementFormDefault = (qualified | unqualified) : unqualified

https://www.w3.org/TR/xmlschema11-1/#dcl.elt.local

2 If targetNamespace is not present and one of the following is true
2.1 form = qualified
2.2 form is absent and the ancestor has elementFormDefault = qualified
then the ·actual value· of the targetNamespace [attribute] of the ancestor element information item, or ·absent· if there is none.

https://www.w3.org/TR/xmlschema11-1/#dcl.att.local

2 If targetNamespace is not present and one of the following is true
2.1 form = qualified
2.2 form is absent and the ancestor has attributeFormDefault = qualified

Here are some concrete implementation test-cases from how it's implemented inside php-src's ext-soap:

Attributes:

• https://github.com/php/php-src/blob/master/ext/soap/tests/schema/schema075.phpt
• https://github.com/php/php-src/blob/master/ext/soap/tests/schema/schema076.phpt
• https://github.com/php/php-src/blob/master/ext/soap/tests/schema/schema077.phpt

Elements:

• https://github.com/php/php-src/blob/master/ext/soap/tests/schema/schema078.phpt
• https://github.com/php/php-src/blob/master/ext/soap/tests/schema/schema079.phpt
• https://github.com/php/php-src/blob/master/ext/soap/tests/schema/schema080.phpt

[goetas]

Thanks