What causes "attribute equal must after attrName" in dianping/cat?

Fix the tag so every '=' directly follows an attribute name: .

dianping/cat · error · Error

attribute equal must after attrName

Error message

attribute equal must after attrName

What it means

Error from the hand-rolled SAX attribute state machine in the ACE XML worker (worker-xml.js:~1517). The tokenizer walks a start tag character by character with states S_TAG/S_ATTR/S_EQ/S_V/S_E/S_C; an '=' is legal only in S_ATTR (right after an attribute name) or S_ATTR_S. In any other state the '=' is meaningless, so the parser throws to abort the tag scan.

Source

Thrown at cat-home/src/main/webapp/assets/js/editor/worker-xml.js:1517

	return t;
	
}
function parseElementStartPart(source,start,el,entityReplacer,errorHandler){
	var attrName;
	var value;
	var p = ++start;
	var s = S_TAG;//status
	while(true){
		var c = source.charAt(p);
		switch(c){
		case '=':
			if(s === S_ATTR){//attrName
				attrName = source.slice(start,p);
				s = S_EQ;
			}else if(s === S_ATTR_S){
				s = S_EQ;
			}else{
				throw new Error('attribute equal must after attrName');
			}
			break;
		case '\'':
		case '"':
			if(s === S_EQ){//equal
				start = p+1;
				p = source.indexOf(c,start)
				if(p>0){
					value = source.slice(start,p).replace(/&#?\w+;/g,entityReplacer);
					el.add(attrName,value,start-1);
					s = S_E;
				}else{
					throw new Error('attribute value no end \''+c+'\' match');
				}
			}else if(s == S_V){
				value = source.slice(start,p).replace(/&#?\w+;/g,entityReplacer);
				el.add(attrName,value,start);
				errorHandler.warning('attribute "'+attrName+'" missed start quot('+c+')!!');

View on GitHub (pinned to e815e74d4c)

Solutions

Fix the tag so every '=' directly follows an attribute name: <tag attr="value">.
Remove stray '=' characters or duplicated equals inside the flagged start tag.
If template syntax (e.g. {{...}} or =expr) is intentional, route the buffer through a worker/mode that understands that template language instead of the XML worker.

Example fix

<!-- before -->
<div =class="box">...</div>

<!-- after -->
<div class="box">...</div>

Defensive patterns

Strategy: validation

Validate before calling

// Before parsing user XML, reject tags with '=' not preceded by a name:
function attributesWellFormed(tagText) {
  return /^<\s*[\w:.-]+(\s+[\w:.-]+\s*=\s*("[^"]*"|'[^']*'|\S+))?\s*\/?>$/.test(tagText.trim());
}

Try / catch

try {
  parseStartTag(source, start, tagNameReplacer);
} catch (ex) {
  if (/attribute/.test(ex.message)) reportXmlError(ex); else throw ex;
}

Prevention

Always write name=value pairs; '=' never stands alone.
Run xmllint on generated XML in CI.
Remember the worker re-parses per keystroke — transient tag errors are normal while typing.

When it happens

Trigger: Malformed attribute syntax such as '<tag =foo>' (equals before any name), '<tag a=="1">' (double equals), or '<tag a b="x">=' sequences where the scanner meets '=' after a value or quote state. The switch default at line 1513-1515 throws.

Common situations: Hand-edited or templated XML/JSP/HTML where an attribute placeholder got mangled, templating engines emitting '=expr' bindings into an XML worker, or partial typing in the editor while the worker re-parses on each keystroke.

Related errors

AI-assisted analysis of dianping/cat@e815e74d4c (2026-08-14). Data as JSON: /api/errors/2b1b26cce2687721. Report an issue: GitHub.