What causes "Error parsing the ${name} attribute value. ${e}" in octobercms/october?

Change the tag from `{% partial "name" lazy %}` to `{% ajaxPartial "name" lazy %}` — lazy mode is only supported there.

octobercms/october · error · Error

Error parsing the ${name} attribute value. ${e}

Error message

Error parsing the ${name} attribute value. ${e}

What it means

October CMS's `{% partial %}` Twig tag renders immediately, while the `lazy` keyword (deferred, AJAX-loaded content) belongs only to the `{% ajaxPartial %}` tag. In PartialTokenParser::parse, `$isAjax` is true only when getTag() returns 'ajaxPartial'; a `lazy` NAME token inside a plain `{% partial %}` is therefore rejected at compile time with this SyntaxError. The message deliberately points you at ajaxPartial because that is the tag that supports lazy mode.

Source

Thrown at modules/backend/assets/foundation/controls/autocomplete/autocomplete.js:384

    $.fn.autocomplete.noConflict = function () {
        $.fn.autocomplete = old
        return this
    }


    /* AUTOCOMPLETE DATA-API
     * ================== */

    function paramToObj(name, value) {
        if (value === undefined) value = ''
        if (typeof value == 'object') return value

        try {
            return oc.parseJSON("{" + value + "}")
        }
        catch (e) {
            throw new Error('Error parsing the '+name+' attribute value. '+e)
        }
    }

    $(document).on('focus.autocomplete.data-api', '[data-control="autocomplete"]', function (e) {
        var $this = $(this)
        if ($this.data('autocomplete')) return

        var opts = $this.data()

        if (opts.source) {
            opts.source = paramToObj('data-source', opts.source)
        }

        $this.autocomplete(opts)
    })

}(window.jQuery);

View on GitHub (pinned to b608633a7e)

Solutions

Change the tag from `{% partial "name" lazy %}` to `{% ajaxPartial "name" lazy %}` — lazy mode is only supported there.
If you do not want AJAX/deferred loading, simply remove the `lazy` keyword from the `{% partial %}` tag.
If you meant a parameter literally named lazy, write it as a pair: `{% partial "name" lazy=true %}` (this parses as an expression and is not treated as the keyword).

Example fix

// before
{% partial "cards" lazy %}

// after
{% ajaxPartial "cards" lazy %}

Defensive patterns

Strategy: validation

Validate before calling

// Lint templates before deploy: flag `lazy` used inside a plain {% partial %} tag
$contents = file_get_contents($templatePath);
if (preg_match('/{%-?\s*partial\b[^%]*?\blazy\b(?!\s*=)/', $contents)) {
    throw new RuntimeException("{$templatePath}: `lazy` requires the {% ajaxPartial %} tag");
}

Try / catch

// Parsing happens at compile time; surface it cleanly instead of a 500
templateSyntax: try {
    $twig->load($templateName);
} catch (Twig\Error\SyntaxError $e) {
    // $e->getMessage() includes the file and line, e.g. the ajaxPartial hint
    Log::warning('Template syntax: '.$e->getMessage());
}

Prevention

Use {% ajaxPartial %} whenever a partial needs lazy or deferred loading.
Run a template lint/compile step in CI so tag misuse fails the build, not the page.
Write lazy parameters as key=value if the word lazy is genuinely a parameter name.

When it happens

Trigger: Writing `{% partial "cards" lazy %}` in any CMS page, layout or partial template. Any template that contains the word `lazy` as a bare keyword (not `lazy=...` and not part of a hyphenated name) inside a `{% partial %}` tag fails the moment Twig parses the template.

Common situations: Copying a lazy-loading example from the ajaxPartial docs but keeping the `partial` tag name; upgrading a project where templates previously used `ajaxPartial`-style syntax on the wrong tag; following tutorials that mix the two tags.

Related errors

AI-assisted analysis of octobercms/october@b608633a7e (2026-08-21). Data as JSON: /api/errors/d0b08a79cf9700f5. Report an issue: GitHub.