wp-cli: wp term generate xxxxx – Error: ‘xxxxx’ is not a registered taxonomy

I figured out a way, although it feels a bit wrong.

First test if the taxonomy exists (which it doesn’t… the first time at least), and then create it as part of the process…

if (! taxonomy_exists($this->taxonomy_manufacturer)) {
     register_taxonomy($this->taxonomy_manufacturer, 'product');
}

if (! term_exists($manufacturer['name'], $this->taxonomy_manufacturer)) {
     wp_insert_term($manufacturer['name'], $this->taxonomy_manufacturer);
}

Caveat, register_taxonomy warns of impending doom if it’s called outside of init. I’m not sure of the implications of it in my scenario, and I’ll report back if my spideysense starts tingling, but so far so good.