lukeshu wrote:

mkinitcpio depends=(systemd) because it depends on udev, and for a while now, udev is part of systemd (accordingly, systemd provides=(udev)).

I believe that this is the only thing making mkinitcpio unsuitable for use with OpenRC.

Upstream issue: https://bugs.archlinux.org/task/59364

This type of change can go in libre:

blacklist.txt: [technical] Edit package metadata for OpenRC compat

Sounds good. Note, however, that the [nonsystemd] version of mkinitcpio uses the following patch:
https://git.parabola.nu/abslibre.git/tree/nonsystemd/mkinitcpio/nosystemd.patch

Although it might not be a big deal for different init systems, we could make a similar patch modifying init_functions only with something like

        # ensure that root is going to be mounted rw. Otherwise, systemd
        # might fsck the device again. Annoy the user so that they fix this.
        init=$(ls -l init | sed 's/.*-> //')
        if [ "${rwopt:-ro}" != 'rw' ] && [ ${init##*/} = systemd ]; then
            echo "********************** WARNING **********************" 
            echo "*                                                   *" 
            echo "*  The root device is not configured to be mounted  *" 
            echo "*  read-write! It may be fsck'd again later.        *" 
            echo "*                                                   *" 
            echo "*****************************************************" 
        fi

That warning applies just as much to openrc; openrc might fsck it again too.