Improvements on append_to_selector method

[spacedmonkey]

Backport from ​https://github.com/WordPress/gutenberg/pull/47833

Trac ticket: https://core.trac.wordpress.org/ticket/58231

[spacedmonkey]

Ping @hellofromTonya

[flixos90]

Related: #58193

Maybe we should add that to Gutenberg first and then backport. See ​https://github.com/WordPress/wordpress-develop/pull/4380#issuecomment-1522910737

I see this backports ​https://github.com/WordPress/gutenberg/pull/47833 and ​https://github.com/WordPress/gutenberg/pull/48759 Noting so we don't forget linking this to the original gutenberg PRs and the props to t-hamano.

I also see that there is a related ticket https://core.trac.wordpress.org/ticket/58193 and that Felix mentioned he'll work on backporting everything ​https://github.com/WordPress/gutenberg/pull/47833#issuecomment-1532196824

Changes seem fine to me, though.

There is no process for backports, it changes from person to person. I can share what I do when I backport and what I find helpful:

• Link to all the Gutenberg PRs that are backported in the PR description (in addition to the trac ticket).
• Link to the backport PR in the original Gutenberg PRs: ​https://github.com/WordPress/gutenberg/pull/47833#issuecomment-1536176801 and ​https://github.com/WordPress/gutenberg/pull/48759#issuecomment-1536173547

Not that this is mandatory in any way, though I've found it very helpful.

[mukesh27]

This ticket was discussed in the recent Performance bug scrub.

This is a backport that was missed from the Gutenberg repo. I think it's likely good to commit, but probably should get a code review on the PR.

Additional props to @joemcgill

[spacedmonkey]

In 55907:

Editor: Improve the append_to_selector method.

Improve append_to_selector method in WP_Theme_JSON by checking to see if string contains a common before imploding / exploding string, which improves performance.

Originally developed and tested in [WordPress/gutenberg#47833 Gutenberg PR 47833].

Props spacedmonkey, flixos90, mukesh27, joemcgill, wildworks, oandregal, mamaduka.
Fixes #58231.

Hi! To confirm, this is meant to be a separate piece from #4380?

I added this PR to the 6.3 board, please feel free to move it to "needs core commit" if it's good to go!

Committed. https://core.trac.wordpress.org/changeset/55907

Hi! To confirm, this is meant to be a separate piece from #4380?

I added this PR to the 6.3 board, please feel free to move it to "needs core commit" if it's good to go!

@tellthemachines I committed as I wanted to unblock my ticket. Let's backport that separately.

Thanks @spacedmonkey !