If Site Title is empty don't use '[ ]' as site title in email but domain name

[Presskopp]

In the email you get when a plugin was automatically updated or if core has been updated, if no site title is set, you'll get something like:

[] Your site has updated ...

while it should be something like [site title] Your site has updated ...

In that case I'd like to see the domain name as the title like in

[example.com] Your site has updated ...

This could be archived by something like

if ( '' != $site_title ) {
        $site_title = wp_specialchars_decode( get_bloginfo( 'name' ), ENT_QUOTES );
        } else {
        $site_title = parse_url( home_url(), PHP_URL_HOST );
        }

in class-wp-automatic-updater.php ~ L.1350

https://core.trac.wordpress.org/ticket/54760

Trac ticket:

[kebbet]

Added the same logics to the function send_plugin_theme_email that uses the same original pattern, in the linked PR.

[audrasjb]

Looks like a nice improvement for 6.0 :)

[audrasjb]

The patch looks good but the same logic should also be used in other emails that are using [%s] (where %s stands for get_bloginfo( 'name' ).

[kebbet]

Ok, I can adjust the patch for that, can only find one more place: in user.php on L592.

What about get_option( 'blogname' )? I.e. user-new.php L130.

Hi @kebbet good work, i have a suggestion, can we wrap the new block in new function, that will be nice as the block is repetitive now. what do you think about?

Thanks @mauriac, I was thinking the same, but was unsure about where to place that functions. Any suggestions?

I'll suggest src/wp-admin/includes/functions.php.

But let's ask committers if they're ok with that, and may be they have any suggestion.

@SergeyBiryukov @audrasjb

wp-admin/includes/functions.php would work, but I'm not sure a specific function is really needed for this… any thought @SergeyBiryukov ?

[audrasjb]

As I'm not sure this feature deserves its own function, let's commit it as it is right now. We can still add the function later if needed.

[audrasjb]

In 53063:

Mail: Replace empty site title with domain name in email subjects.

This change replaces site title with domain name in email subjects when the blogname option is empty.

Props Presskopp, kebbet, audrasjb, azouamauriac.
Fixes #54760.

committed in https://core.trac.wordpress.org/changeset/53063