What causes "Avoid default element namespace declarations." in dianping/cat?

Replace the default element namespace with a prefixed declaration: 'declare namespace ns = "http://example.com/ns";' and prefix element tests/literals (ns:element).

dianping/cat · warning · StaticWarning

W06

W06

Error message

Avoid default element namespace declarations.

What it means

Style warning W06 raised by the XQuery static-analysis pass in the ACE XQuery worker (worker-xquery.js:1460-1475). The translator hooks URILiteral: when it sees 'declare default element namespace "..."' (fn flag not set, so the URI belongs to an element-namespace declaration) it throws a StaticWarning advising against default element namespaces. Warnings are collected and reported as editor annotations; they do not abort parsing.

Source

Thrown at cat-home/src/main/webapp/assets/js/editor/worker-xquery.js:1468

            });
        }
    };
};

exports.DefaultNamespaceDecl = function(translator, rootSctx, node) {
    var fn = false;
    var ns = '';

    return {
        TOKEN: function(token){
            fn = fn ? true : (token.value === 'function');
        },
        URILiteral: function(uri){
            ns = TreeOps.flatten(uri);
            ns = ns.substring(1, ns.length - 1);
            if(!fn) {
                translator.apply(function(){
                    throw new StaticWarning('W06', 'Avoid default element namespace declarations.', node.pos);
                });
                rootSctx.defaultElementNamespace = ns;
            } else {
                rootSctx.defaultFunctionNamespace = ns;
            }
        }
    };
};

exports.NamespaceDecl = function(translator, rootSctx, node) {
    var prefix = '';
    return {
        NCName: function(ncname) {
            prefix = TreeOps.flatten(ncname);
        },
        URILiteral: function(uri) {
            uri = TreeOps.flatten(uri);
            uri = uri.substring(1, uri.length - 1);

View on GitHub (pinned to e815e74d4c)

Solutions

Replace the default element namespace with a prefixed declaration: 'declare namespace ns = "http://example.com/ns";' and prefix element tests/literals (ns:element).
If the default namespace is intentional and team style accepts it, configure the editor to hide W06-level warnings.
Update all unprefixed element names/tests in the module to use the new prefix after switching.

Example fix

(: before :)
declare default element namespace "http://example.com/ns";
/doc//item

(: after :)
declare namespace ns = "http://example.com/ns";
/ns:doc//ns:item

Defensive patterns

Strategy: validation

Validate before calling

// Flag default element namespace declarations before linting:
function usesDefaultElementNamespace(xquery) {
  return /declare\s+default\s+element\s+namespace/.test(xquery);
}

Type guard

function isStaticWarning(ex) {
  return ex instanceof StaticWarning || /^W\d+$/.test(ex.code || '');
}

Try / catch

translator.apply(function () {
  try { fn(); }
  catch (ex) {
    if (isStaticWarning(ex)) warnings.push({ code: ex.code, pos: ex.pos, message: ex.message });
    else throw ex;
  }
});

Prevention

Declare namespaces with prefixes and use prefixed names throughout the module.
Treat W06 as style-only: it never blocks parsing or execution.
Filter by code 'W06' in the editor annotation pipeline if the team accepts default namespaces.

When it happens

Trigger: An XQuery module containing 'declare default element namespace "http://example.com/ns";'. The URILiteral handler sees fn===false, so translator.apply throws StaticWarning('W06', ...) at line 1466-1468 while still recording rootSctx.defaultElementNamespace = ns.

Common situations: XQuery written for a single-namespace document model where authors default the namespace to avoid prefixes; eXist-db/BaseX modules; code style rules that require explicit prefixes so every element's namespace is visible at the element site.

Related errors

AI-assisted analysis of dianping/cat@e815e74d4c (2026-08-14). Data as JSON: /api/errors/006f06b622052039. Report an issue: GitHub.