[CXF-9021] Warning "Could not resolve Schema for datatypes.dtd" when file was found

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 4.0.4
• Fix Version/s: 4.1.0, 3.5.10, 3.6.5, 4.0.6
• Component/s: Core
• Estimated Complexity: Moderate
• Assignee: Freeman Yue Fang
• Reporter: Michael Kroll
• Created: 28/May/24 14:35
• Updated: 20/Nov/24 17:06
• Resolved: 20/Nov/24 17:05

Description

Assuming you have

• system property javax.xml.accessExternalDTD set to all or file
• enabled out validation
• an xsd that references a DTD

And fire a request, the following log appears:

WARN [org.apa.cxf.ws.add.EndpointReferenceUtils] Could not resolve Schema for ../dtd/XMLSchema.dtd

The request is then correctly validated, despite the warning. Tested with both valid and invalid equests.

Looking at the code:

            if (impl == null) {
    [...] // if found in schemas map:
            return impl;
    if (systemId != null) {
        [...] // if found by systemId:
                return impl;
    }
    if (namespaceURI != null) {
        [...] // if found by namespaceURI:
                return impl;
    }
    [...]
    if (systemId == null) {
        systemId = publicId;
    }
    if (systemId != null) {
        InputSource source = resolver.resolve(systemId, baseURI);
        if (source != null) {
            impl = new LSInputImpl();
            impl.setByteStream(source.getByteStream());
            impl.setSystemId(source.getSystemId());
            impl.setPublicId(source.getPublicId());
+            ### the code above is run, source is found, impl is set
+            ### i miss a 'return impl;' here, to match the code above
        }
    }
    LOG.warning("Could not resolve Schema for " + systemId);
}
return impl;

I added two inline 'comments', starting with ### to mark the place where i miss a return statement.
Reasoning:

1. all of the above happens in an if block: if (impl==null)
2. it seems that with different searches eg. via namespaceURI and systemId, the variable impl should be filled and then returned
3. the warning in the last line says 'Could not resolve Schema'
4. but the code directly above it may indeed find a source and fill impl
5. so the schema (in my case a DTD) is found. I can verify that by looking into debug values. And the validation then takes place, with expected outcomes.
6. first finding the schema and then printing that it could not be found is misleading

proposed solution:

• either a return impl; statement like mentioned above
• or guard the warning with if (impl==null)