[XERCESC-2232] xsi:nil="false" fails validation for child elements

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Duplicate
• Affects Version/s: 3.2.3
• Component/s: Validating Parser (XML Schema)

Language

C++

• Assignee: Unassigned
• Reporter: Alan Howells
• Created: 30/Nov/21 11:02
• Updated: 01/Dec/21 13:20
• Resolved: 01/Dec/21 13:20

Description

We have recently found an issue with xsi:nil="false"

Running the following code (also attached):

#include <iostream>
#include <string>
#include <xercesc/dom/DOMException.hpp>
#include <xercesc/framework/MemBufInputSource.hpp>
#include <xercesc/parsers/XercesDOMParser.hpp>
#include <xercesc/sax/ErrorHandler.hpp>
#include <xercesc/sax/SAXParseException.hpp>

namespace
{
    class XMLValidatorErrorHandler : public xercesc::ErrorHandler
    {
    public:
        void warning(const xercesc::SAXParseException &e) final
        {
            std::cerr << "Warning at file "
                      << xercesc::XMLString::transcode(e.getSystemId())
                      << ", line " << e.getLineNumber() << ", char "
                      << e.getColumnNumber() << ".  Message: "
                      << xercesc::XMLString::transcode(e.getMessage()) << "\n";
        }

        void error(const xercesc::SAXParseException &e) final
        {
            std::cerr << "Error at file "
                      << xercesc::XMLString::transcode(e.getSystemId())
                      << ", line " << e.getLineNumber() << ", char "
                      << e.getColumnNumber() << ".  Message: "
                      << xercesc::XMLString::transcode(e.getMessage()) << "\n";
        }

        void fatalError(const xercesc::SAXParseException &e) final
        {
            std::cerr << "Fatal Error at file "
                      << xercesc::XMLString::transcode(e.getSystemId())
                      << ", line " << e.getLineNumber() << ", char "
                      << e.getColumnNumber() << ".  Message: "
                      << xercesc::XMLString::transcode(e.getMessage()) << "\n";
        }

        void resetErrors() final
        {
        }
    };
} // namespace

int
main(int argc, char **argv)
{
    static_cast<void>(argc);
    static_cast<void>(argv);

    xercesc::XMLPlatformUtils::Initialize();

    std::string inputXml(
        "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
        "<ns1:NillableElement"
        "    xmlns:ns1=\"http://example.com/Nillable\"\n"
        "    xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"\n"
        "    xsi:schemaLocation=\"http://example.com/Nillable Nillable.xsd\"\n"
        "    xsi:nil=\"false\">\n"
        "  <ns1:Val1>v1</ns1:Val1>\n"
        "</ns1:NillableElement>\n");

    std::string inputSchema(
        "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n"
        "<xs:schema"
        "    xmlns:xs=\"http://www.w3.org/2001/XMLSchema\"\n"
        "    xmlns:tns=\"http://example.com/Nillable\"\n"
        "    xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"\n"
        "    targetNamespace=\"http://exampl.com/Nillable\"\n"
        "    elementFormDefault=\"qualified\">\n"
        "  <xs:complexType name=\"TestType\">\n"
        "    <xs:sequence>\n"
        "      <xs:element name=\"Val1\" type=\"xs:string\"/>\n"
        "    </xs:sequence>\n"
        "  </xs:complexType>\n"
        "  <xs:element name=\"NillableElement\" type=\"tns:TestType\" "
        "nillable=\"true\"/>\n"
        "  <xs:element name=\"NonNillableElement\" type=\"tns:TestType\" "
        "nillable=\"false\"/>\n"
        "</xs:schema>\n");

    xercesc::XercesDOMParser parser;
    parser.setValidationScheme(xercesc::XercesDOMParser::Val_Always);
    parser.setDoNamespaces(true);
    parser.setDoSchema(true);
    parser.setValidationSchemaFullChecking(true);
    parser.cacheGrammarFromParse(true);
    parser.useCachedGrammarInParse(true);

    XMLValidatorErrorHandler errorHandler;
    parser.setErrorHandler(&errorHandler);

    try {
        // Get Schema Input Source
        xercesc::MemBufInputSource schemaInputSource(
            reinterpret_cast<const XMLByte *>(inputSchema.c_str()),
            static_cast<XMLSize_t>(inputSchema.size()),
            "schema");
        parser.loadGrammar(
            schemaInputSource, xercesc::Grammar::SchemaGrammarType, true);
    }
    catch (const xercesc::XMLException &e) {
        std::cerr << "Fatal Error during schema parsing: "
                  << xercesc::XMLString::transcode(e.getMessage()) << "\n";
        return EXIT_FAILURE;
    }
    catch (const xercesc::DOMException &e) {
        std::cerr << "Fatal Error during schema parsing: "
                  << xercesc::XMLString::transcode(e.getMessage()) << "\n";
        return EXIT_FAILURE;
    }

    // Validate the XML against the Schema.
    try {
        // Get XML Input Source
        xercesc::MemBufInputSource xmlInputSource(
            reinterpret_cast<const XMLByte *>(inputXml.c_str()),
            static_cast<XMLSize_t>(inputXml.size()),
            "xml");
        parser.parse(xmlInputSource);
    }
    catch (const xercesc::XMLException &e) {
        std::cerr << "Fatal Error during xml parsing: "
                  << xercesc::XMLString::transcode(e.getMessage()) << "\n";
        return EXIT_FAILURE;
    }
    catch (const xercesc::DOMException &e) {
        std::cerr << "Fatal Error during xml parsing: "
                  << xercesc::XMLString::transcode(e.getMessage()) << "\n";
        return EXIT_FAILURE;
    }

    return EXIT_SUCCESS;
}
 

returns the following validation error:

Error at file xml, line 6, char 13.  Message: 'xsi:nil' specified for non-nillable element 'Val1' 

But:

• Only the NillableElement is marked as nillable in the schema, not Val1.
• Only NillableElement element is marked as xsi:nil="false" in the xml, not Val1.
• xsi:nil is not specified for Val1

Issue Links

• duplicates: XERCESC-1952 Different validation results for different empty element syntax: <e xsi:nil="true" /> vs. <e xsi:nil="true"></e>
• relates to: XERCESC-1952 Different validation results for different empty element syntax: <e xsi:nil="true" /> vs. <e xsi:nil="true"></e>