Plugin: Guard code from redeclaration errors after WP core merge

[gziolo]

What?

Part of #39889.

It is expected to declare functions and classes only when they are missing in WordPress core. As soon as we backport the files updated in this PR to WordPress core, they will work only as a fallback for older versions of WordPress.

Why?

To avoid fatal errors because of redeclared functions and classes.

How?

I followed the guidelines at https://github.com/WordPress/gutenberg/tree/trunk/lib#wrap-functions-and-classes-with--function_exists-and--class_exists.

Testing Instructions

There are unit tests that cover those files and they should continue to pass.

We should also test that webfonts API and block patterns continue to work in the editor.

[gziolo]

@jsnajdr – have you started the process of backporting changes related to block patterns to WordPress core?

@aristath – have you started the process of backporting changes related to web fonts API to WordPress core?

[gziolo]

I opened #39889 to coordinate the backporting tasks.

[gziolo]

To make the review process it's possible to check the diff with all the whitespace changes removed:

https://github.com/WordPress/gutenberg/pull/39888/files?diff=unified&w=1

[adamziel]

❤️ this is great, thank you! The E2E failure seems to be unrelated, I restarted that check.

[jsnajdr]

have you started the process of backporting changes related to block patterns to WordPress core?

No I haven't yet, I guess I'm supposed to submit a Core patch that adds the block patterns endpoints? They are currently in the __experimental namespace. Is that OK for Core or should they graduate to wp/v2 as part of the process? The endpoints are quite straightforward and stable, hard to think of any radical change they would potentially need.

[gziolo]

❤️ this is great, thank you! The E2E failure seems to be unrelated, I restarted that check.

Yes, the same issue with tests as in #39904 (comment). Merged PR passed all checks in trunk 🤷🏻

[aristath]

@aristath – have you started the process of backporting changes related to web fonts API to WordPress core?

Not yet... I'm still unclear about whether we'll merge this API in 6.0, or not, because there are a few PRs related to the webfonts API from folks, so I'm waiting to see if there is a consensus for them and what will happen 👍

[gziolo]

have you started the process of backporting changes related to block patterns to WordPress core?

No I haven't yet, I guess I'm supposed to submit a Core patch that adds the block patterns endpoints? They are currently in the __experimental namespace. Is that OK for Core or should they graduate to wp/v2 as part of the process? The endpoints are quite straightforward and stable, hard to think of any radical change they would potentially need.

It looks like @hellofromtonya started looking into bringing those endpoints to WordPress core in WordPress/wordpress-develop#2488. I see files listed in the description but no code changes so far. I'm sure the __experimental namespace will get removed as part of the process.

@aristath – have you started the process of backporting changes related to web fonts API to WordPress core?
Not yet... I'm still unclear about whether we'll merge this API in 6.0, or not, because there are a few PRs related to the webfonts API from folks, so I'm waiting to see if there is a consensus for them and what will happen 👍

Thank you @aristath, I will keep an eye on the webfonts API 👍🏻