ExpressionEngine Matrix :total_rows doesn't work when no rows

Question

Matrix 2.5 and 2.6 on ExpressionEngine 2.7.3.

The :total_rows property doesn't work when there are no rows. It works fine when there are rows.

Below isn't actual code, but it's showing the gist.

{exp:channel:entries dynamic="no" channel="regions" url_title="[url_title]"}
    {if "{social_networks:total_rows}" > 0}
        {!--  Do the things --}
    {if:else}
        {!--  Don't do the things --}
    {/if}
{/exp:channel:entries}

Outputting {social_networks:total_rows} is an empty string (which I can't even match against with a conditional) until there's a Matrix row.

Has anyone else noticed this? I don't want to have to start pulling the plugin apart.

Answer 1

I believe when there are zero rows the matrix variable just returns false, so you can just use it in the conditional like this.

{exp:channel:entries dynamic="no" channel="regions" url_title="[url_title]"}
    {if social_networks}
        {!--  Do the things --}
    {if:else}
        {!--  Don't do the things --}
    {/if}
{/exp:channel:entries}

Answer 2

{matrix:total_rows} can't work if there are no rows in the field simply because EE doesn't parse any field tags that don't have any actual data. Matrix never even gets called and the tag gets replaced with nothing.