Fix assertion for XML without documentElement, but with elements

[kvarec]

Fix assertion for XML document with elements, but without documentElement.

[rleigh-codelibre]

Would it be possible to provide a small self-contained example which triggers the assertion?

[kvarec]

Ok, I will try to do it.

[kvarec]

Example1.cpp

#include <xalanc/Include/PlatformDefinitions.hpp>

#include <xercesc/util/PlatformUtils.hpp>
#include <xercesc/dom/DOM.hpp>
#include <xercesc/dom/impl/DOMDocumentImpl.hpp>

#include <xalanc/XPath/XPathEvaluator.hpp>
#include <xalanc/XalanSourceTree/XalanSourceTreeDOMSupport.hpp>
#include <xalanc/XalanSourceTree/XalanSourceTreeInit.hpp>
#include <xalanc/XalanSourceTree/XalanSourceTreeParserLiaison.hpp>
#include <xalanc/XercesParserLiaison/XercesDocumentWrapper.hpp>

int main()
{
    using xercesc::XMLPlatformUtils;
    using xalanc::XPathEvaluator;

    XMLPlatformUtils::Initialize();
    XPathEvaluator::initialize();
    {
        using xalanc::XalanDOMString;
        using xalanc::XalanSourceTreeInit;
        using xalanc::XalanSourceTreeDOMSupport;
        using xalanc::XalanSourceTreeParserLiaison;
        using xalanc::XalanElement;
        using xalanc::XPath;
        using xalanc::XalanNode;

        XalanSourceTreeInit theSourceTreeInit;
        XalanSourceTreeDOMSupport theDOMSupport;
        XalanSourceTreeParserLiaison theLiaison(theDOMSupport);

        theDOMSupport.setParserLiaison(&theLiaison);
        
        XalanElement* theContextNode = 0;
        {
            using namespace xercesc;
            using xalanc::XercesDocumentWrapper;

            DOMImplementation* theDOMImpl = DOMImplementation::getImplementation();
            DOMDocument* theDocument = theDOMImpl->createDocument();
            DOMNode *theNode = theDocument->createElement(XalanDOMString("NODE").c_str());
           
            MemoryManager* theManager = GET_DIRECT_MM(theDocument);
            auto theWrapper = XercesDocumentWrapper::create(*theManager, theDocument, false, false, false);

            theContextNode = static_cast<XalanElement*>(theWrapper->mapNode(theNode));
        }

        XPathEvaluator().selectSingleNode(
                theDOMSupport,
                theContextNode,
                XalanDOMString("//NODE").c_str());
    }

    XPathEvaluator::terminate();
    XMLPlatformUtils::Terminate();

    return 0;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.2)

project(example1 CXX)

find_package(XercesC REQUIRED)
find_package(XalanC REQUIRED)

include_directories(
  ${XercesC_INCLUDE_DIRS}
  ${XalanC_INCLUDE_DIRS}
)

add_executable(${PROJECT_NAME}
  Example1.cpp
)

target_link_libraries(${PROJECT_NAME}
  ${XercesC_LIBRARIES}
  ${XalanC_LIBRARIES}
)

Move CmakeLists.txt and Example1.cpp to somw dir (for example named "src") and execute:
cmake src && make && ./example1

From gdb:

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff79d6cb6 in xalanc_1_11::XPath::findRoot(xalanc_1_11::XPathExecutionContext&, xalanc_1_11::XalanNode*, int const*, int, xalanc_1_11::MutableNodeRefList&) const () from /lib/x86_64-linux-gnu/libxalan-c.so.111
(gdb) bt
#0  0x00007ffff79d6cb6 in xalanc_1_11::XPath::findRoot(xalanc_1_11::XPathExecutionContext&, xalanc_1_11::XalanNode*, int const*, int, xalanc_1_11::MutableNodeRefList&) const () from /lib/x86_64-linux-gnu/libxalan-c.so.111
#1  0x00007ffff79dea5a in xalanc_1_11::XPath::step(xalanc_1_11::XPathExecutionContext&, xalanc_1_11::XalanNode*, int const*, xalanc_1_11::MutableNodeRefList&) const () from /lib/x86_64-linux-gnu/libxalan-c.so.111
#2  0x00007ffff79dfd5a in xalanc_1_11::XPath::locationPath(xalanc_1_11::XalanNode*, int const*, xalanc_1_11::XPathExecutionContext&) const () from /lib/x86_64-linux-gnu/libxalan-c.so.111
#3  0x00007ffff79dbaf4 in xalanc_1_11::XPath::executeMore(xalanc_1_11::XalanNode*, int const*, xalanc_1_11::XPathExecutionContext&) const () from /lib/x86_64-linux-gnu/libxalan-c.so.111
#4  0x00007ffff79dc2b7 in xalanc_1_11::XPath::execute(xalanc_1_11::XalanNode*, xalanc_1_11::PrefixResolver const&, xalanc_1_11::XPathExecutionContext&) const () from /lib/x86_64-linux-gnu/libxalan-c.so.111
#5  0x00007ffff79d531e in xalanc_1_11::XPathEvaluator::evaluate(xalanc_1_11::DOMSupport&, xalanc_1_11::XalanNode*, xalanc_1_11::XPath const&, xalanc_1_11::PrefixResolver const&, xalanc_1_11::XPathEnvSupport&) ()
   from /lib/x86_64-linux-gnu/libxalan-c.so.111
#6  0x00007ffff79d5ca1 in xalanc_1_11::XPathEvaluator::evaluate(xalanc_1_11::DOMSupport&, xalanc_1_11::XalanNode*, char16_t const*, xalanc_1_11::PrefixResolver const&, xalanc_1_11::XPathEnvSupport&) ()
   from /lib/x86_64-linux-gnu/libxalan-c.so.111
#7  0x00007ffff79d5deb in xalanc_1_11::XPathEvaluator::evaluate(xalanc_1_11::DOMSupport&, xalanc_1_11::XalanNode*, char16_t const*, xalanc_1_11::XalanElement const*) () from /lib/x86_64-linux-gnu/libxalan-c.so.111
#8  0x00007ffff79d5ea7 in xalanc_1_11::XPathEvaluator::selectSingleNode(xalanc_1_11::DOMSupport&, xalanc_1_11::XalanNode*, char16_t const*, xalanc_1_11::XalanElement const*) () from /lib/x86_64-linux-gnu/libxalan-c.so.111
#9  0x0000555555557640 in main () at /home/user/dev/xalan-c_example1/src/Example1.cpp:50