dianping/cat · error · ValidationError

Expected ({}) but found '{}'.

Error message

Expected ({}) but found '{}'.

What it means

The total-miss branch of `Validation.singleProperty`: no token of the value matched the expected type expression at all (`result` false and the expression is at its first token), so it throws `ValidationError("Expected (" + types + ") but found 'value'")` anchored at the value's position. The message interpolates the internal type expression (e.g. `<length> | <percentage> | inherit`), which is exactly what the property accepts.

Source

Thrown at cat-home/src/main/webapp/assets/js/editor/worker-css.js:5169

        var result      = false,
            value       = expression.value,
            count       = 0,
            part;

        while (expression.hasNext() && count < max) {
            result = ValidationTypes.isAny(expression, types);
            if (!result) {
                break;
            }
            count++;
        }

        if (!result) {
            if (expression.hasNext() && !expression.isFirst()) {
                part = expression.peek();
                throw new ValidationError("Expected end of value but found '" + part + "'.", part.line, part.col);
            } else {
                 throw new ValidationError("Expected (" + types + ") but found '" + value + "'.", value.line, value.col);
            }
        } else if (expression.hasNext()) {
            part = expression.next();
            throw new ValidationError("Expected end of value but found '" + part + "'.", part.line, part.col);
        }

    },

    multiProperty: function (types, expression, comma, max) {

        var result      = false,
            value       = expression.value,
            count       = 0,
            sep         = false,
            part;

        while(expression.hasNext() && !result && count < max) {
            if (ValidationTypes.isAny(expression, types)) {

View on GitHub (pinned to e815e74d4c)

Solutions

  1. Read the 'Expected (...)' clause in the message — it lists the accepted types/keywords verbatim; pick a value matching it.
  2. If the value came from a variable/template, print the rendered CSS and fix the substitution.
  3. If the keyword is valid modern CSS, upgrade the validator table (see unknown-property solutions) since old tables lack new keywords.

Example fix

/* before */
.layer { z-index: high; } /* Expected (<integer> | auto) but found 'high' */

/* after */
.layer { z-index: 10; }
Defensive patterns

Strategy: try-catch

Validate before calling

// mirror the type expression from the error message to pre-check a value you generate
function matchesTypeExpr(types, token) {
  // e.g. types='<integer> | auto'
  if (/integer|number/.test(types) && /^-?\d+$/.test(token)) return true;
  if (/length/.test(types) && /^-?\d+(px|em|rem|%)$/.test(token)) return true;
  return types.split('|').map(function (t) { return t.trim(); }).indexOf(token) !== -1;
}

Try / catch

try {
  Validation.validate(property, value);
} catch (ex) {
  if (/^Expected \(/.test(ex.message)) { addLint(ex.line, ex.col, ex.message); return; } // message contains the accepted grammar
  throw ex;
}

Prevention

When it happens

Trigger: `display: foo`, `z-index: high`, `width: lots`, `overflow: sometimes` — the first value token matches none of the allowed types. Any singleProperty-validated property (`spec` string without `||`, or `multi` with `isFirst()` true) given a completely wrong value.

Common situations: Typos and keyword guesses; values copied from a different property; unquoted templating that substitutes an identifier the grammar cannot match; legacy keywords removed from the table.

Related errors

AI-assisted analysis of dianping/cat@e815e74d4c (2026-08-14). Data as JSON: /api/errors/061095c91e85c0f5. Report an issue: GitHub.