Bind to grammar will add another namespace declaration even when there is an existing one

[datho7561]

If you have an XML document with a namespace declaration:

<root xmlns="http://example.org/schemaNamespace">
  <aaa />
</root>

And then use the CodeLens to bind to a grammar with targetNamespace eg.

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" targetNamespace="http://foo" xmlns:ns="http://foo">
  <xs:element name="root">
    <xs:complexType>
      <xs:sequence>
        <xs:element
            ref="ns:aaa"
            maxOccurs="unbounded"/>
      </xs:sequence>
    </xs:complexType>
  </xs:element>
  <xs:element name="aaa" />
</xs:schema>

Then you will end up with two xmlns in the XML document:

<?xml-model href="document.xsd"?>
<root xmlns="http://example.org/schemaNamespace" xmlns="http://foo" >
  <aaa />
</root>

This happens for binding with XSD and binding with xml-model

[angelozerr]

To fix that we have 2 solutions:

• don't generate the namespace if XML declares already a namespace
• replace the existing namespace with the new namespace.

Perhaps the first solution could be enough (and easy to implement)