Craft 3 and Macros

Question

re: macros I'm trying to use one for an SVG sprite. But I'm not sure what I'm doing wrong.

macros template:

{% macro icon(iconId) %}
    <svg class="icon icon-{{ iconId }}" role="img" title="{{ iconId }}">
        <use xlink:href="{{ url('/assets/images/icons.svg#' ~ iconId) }}"></use>
    </svg>
{% endmacro %}

In my layout template I have this {% import '_macros' as macros %} and in an another template this {{ macros.icon("SIGNAL") }}

Then in the site i get a twig runtime error:

Accessing Twig_Template attributes is forbidden.

and it highlights the line where I extend the layout template.

Not sure why this isn't working.

Without a macro this code works fine. but I want the macro so I don't have to type it out all the time.

<svg class="icon" height="0" width="0">
 <use xlink:href="/assets/images/icons.svg#SIGNAL" />
</svg>

Answer 1

This is a change in how macros work in Twig 2.0, not a Craft CMS issue (though Craft 3 did signal a move to Twig 2.x).

As of Twig 2.0, macros imported in a file are not available in child templates anymore (via an include call for instance). You need to import macros explicitly in each file where you are using them.

https://twig.symfony.com/doc/1.x/deprecated.html

This is also documented in the Craft CMS 3 docs:

https://docs.craftcms.com/v3/changes-in-craft-3.html#twig-2

...so just import the macro again in the child template.