Under heavy cache conditions, updating the parent theme don't reflect changes with child theme enabled

Question

I use W3 Total Cache, Cloudflare (and CloudFront for media files). I use a Child Theme to customize specifically for my site while maintaining the core theme with the parent theme.

Whenever I update the Parent Theme, the changes are not reflected while the Child Theme is the Active Theme.

However, if I re-upload or update the Child Theme's Style.css, it does reflect the new changes. I'm guessing it's the cache.

What do I do, so I don't have to worry about the Child Theme when the updates are with the Parent Theme (while I continue to have the Child Theme as my Active Theme)?

Answer 1

You could use the file modification time (filemtime) to trigger a reload (and recache) of the file.

This is how I usually enqueue styles (and scripts):

$file = '/css/some-styles.css';
wp_enqueue_style(
    'some-styles',
    get_stylesheet_directory_uri().$file,
    array('some-dependency'),
    filemtime(get_stylesheet_directory().$file)
);

This results in something like the following:

<link rel='stylesheet' id='some-styles-css'
    href='.../css/some-styles.css?ver=1388657898' type='text/css' media='all' />

You would have to do this for both the parent and the child theme, though.