Magento2 split static content deployment - multiple jobs not working with multi-language themes

[johnorourke]

Deployer Version

v7

Target OS

Ubuntu 24

Which PHP version are you using?

PHP 7.4

Content of deploy.php or deploy.yaml

set('static_content_jobs', 8);
set('magento_themes', [
    'Magento/luma' => 'en_US en_GB fr_FR de_DE',
    'Acme/brand1' => 'en_GB',
    'Acme/brand2' => 'de_DE fr_FR en_AU',
    'Acme/brand3' => 'de_DE fr_FR en_AU',
    'Acme/brand4' => 'en_GB',
]);

Steps to reproduce

Deploy a Magento 2 instance with the above themes and locales available.

Expected result: it should be able to group the themes with the same locales and run them as one command.

Actual result: if you pass an array of themes and locales, each one is built sequentially so you can't take advantage of multiple processes.

Use case: we have some instances with 90+ themes, and sequential static content build takes about 1.5 hours.

I will send a PR for this issue - so far it tests well.

[johnorourke]

(this appears to be different to #3897 because the job works, it just doesn't do multiple themes at once)