Saxon

Any feedback here that I could use?

Sorry for the lack of response. I've come back to it a couple of times scratching my head, and don't have a clear answer.

The responsibility for inserting space separators and item separators in the receiver pipeline isn't particularly clear. That's partly due to problems with the specs - "item separator" is a bit of an aberration because it's not exclusively concerned with serialization. A problem with the Receiver pipeline is you can assemble components in the pipeline in any order and that can lead to unexpected effects like this. I'll give it some more thought.

No hurry, thanks for the reply Michael!

I reproduced the problem with:

public void testBug6369() {

        String query = "declare namespace output = \"http://www.w3.org/2010/xslt-xquery-serialization\";\n"
                + "declare option output:method 'text';\n"
                + "declare option output:item-separator ', ';\n"
                + "let $xml:=<xml><element>text1</element><element>text2</element></xml> return $xml/element/string()";


        try {
            Processor proc = new Processor(false);
            DocumentBuilder builder = proc.newDocumentBuilder();
            XQueryCompiler compiler = proc.newXQueryCompiler();
            XQueryExecutable exec = compiler.compile(query);
            XQueryExpression expr = exec.getUnderlyingCompiledQuery();
            XQueryEvaluator eval = exec.load();

            Configuration config = proc.getUnderlyingConfiguration();
            SerializerFactory sf = config.getSerializerFactory();
            PipelineConfiguration pipe = config.makePipelineConfiguration();
            SerializationProperties props = new SerializationProperties(
                    exec.getUnderlyingCompiledQuery().getExecutable().getOutputProperties());
            StringWriter sw = new StringWriter();
            Receiver receiver = sf.getReceiver(new StreamResult(sw), props, pipe);
            Receiver tr = new TreeReceiver(receiver);
            expr.run(eval.getUnderlyingQueryContext(), tr, props.getProperties());
            System.err.println(sw.toString());
        } catch (XPathException | SaxonApiException e) {
            e.printStackTrace();
            fail(e);
        }
    }

Hope that's a reasonable interpretation of what you are doing.

So, the TreeReceiver has a decompose() method that inserts a whitespace character between the "text1" and "text2" events, so there are three character events arriving at the SequenceNormallizerWithItemSeparator ("text1", " ", "text2"), and the SequenceNormalizer inserts the item separator between each pair.

The "text1" and "text2" items are hitting the TreeReceiver.append() method rather than the characters() method because the query explicitly makes themstrings, not text nodes, by calling the string() function.

If we cut out the TreeReceiver from the pipeline the result is text1, text2 which I assume is what you want.

I think the basic problem is that you only want a TreeReceiver if you want to deliver the result assembled as an XML document node, and you only want a SequenceNormalizerWithItemSeparator if you want it as a serialized sequence with item separators; you can't have both.

Thanks for the analysis Michael!