usememos/memos · error

size() argument must be a field

Error message

size() argument must be a field

What it means

size() must be applied directly to a field reference. If its single argument is a literal, accessor, or nested function instead of a *FieldRef, the renderer cannot resolve a column to measure and returns this error.

Source

Thrown at internal/filter/render.go:266

	default:
		return "", errors.Errorf("unsupported dialect %q", r.dialect)
	}
	if off != 0 {
		base = fmt.Sprintf("(%s - %d)", base, off)
	}
	return base, nil
}

func (r *renderer) renderFunctionComparison(fn *FunctionValue, op ComparisonOperator, right ValueExpr) (renderResult, error) {
	if fn.Name != "size" {
		return renderResult{}, errors.Errorf("unsupported function %s in comparison", fn.Name)
	}
	if len(fn.Args) != 1 {
		return renderResult{}, errors.New("size() expects one argument")
	}
	fieldArg, ok := fn.Args[0].(*FieldRef)
	if !ok {
		return renderResult{}, errors.New("size() argument must be a field")
	}

	field, ok := r.schema.Field(fieldArg.Name)
	if !ok {
		return renderResult{}, errors.Errorf("unknown field %q", fieldArg.Name)
	}
	if field.Kind == FieldKindVirtualAlias {
		field, ok = r.schema.ResolveAlias(fieldArg.Name)
		if !ok {
			return renderResult{}, errors.Errorf("invalid alias %q", fieldArg.Name)
		}
	}

	value, err := expectNumericLiteral(right)
	if err != nil {
		return renderResult{}, err
	}

View on GitHub (pinned to 14d757ce1f)

Solutions

1. Apply size to a schema field: size(tag) > 2 or content.size() > 100
2. Check the field exists in the filter schema before using it with size()

Example fix

// before
`size("hello") > 3`

// after
`size(tag) > 2`

if _, ok := fn.Args[0].(*filter.FieldRef); !ok {
    return errors.New("size() must wrap a field reference")
}

func isSizeOnField(fn *filter.FunctionValue) bool {
    arg, ok := fn.Args[0].(*filter.FieldRef)
    return ok && arg != nil
}

if err := r.Render(cond); err != nil {
    if strings.Contains(err.Error(), "size() argument must be a field") {
        return userErr("apply size() to a field, e.g. size(tag)")
    }
    return err
}

When it happens

Trigger: Textual CEL like size("hello") > 3 or size([1,2,3]) == 3 — calling size on a list/string literal rather than a schema field; also size(size(tag)) nesting.

Common situations: Users test size() with inline literals before using real fields; copy filters from contexts where size works on arbitrary expressions.

Related errors

• size() expects one argument
• comparison must start with a field reference or supported fu
• IN operator requires a field on the left-hand side
• tags must be compared with string literals
• tag attribute is not configured

AI-assisted analysis of usememos/memos@14d757ce1f (2026-08-15). Data as JSON: /api/errors/61788104493897f0. Report an issue: GitHub.