register_block_type: Accept editor_script array for back-compat

[ockham]

Based on prior work by @nendeb and @costdev in 56707. Quoting that ticket:

I had multiple handles for editor_script and passed the handles to editor_script as an array.
It works fine in WP6.0 but fails in WP61 and the block becomes unusable.
I know that editor_script was deprecated in WP6.1 and changed to editor_script_handles, but please fix it because it is not backward compatible that editor_script cannot be passed as an array.

Props @nendeb@costdev@gziolo

TODO

• Fix getter (see currently failing unit test and @gziolo's comment)
• Ideally test setter separately from getterProbably okay as-is; they're two faces of the same medal.
• Make sure REST API endpoint works -- add tests?
• Update PHPDoc

Trac ticket: https://core.trac.wordpress.org/ticket/56707

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This Pull Request is for code review only. Please keep all other discussion in the Trac ticket. Do not merge this Pull Request. See GitHub Pull Requests for Code Review in the Core Handbook for more details.

[gziolo]

There is one edge case to address that I explained in https://github.com/WordPress/wordpress-develop/pull/3487/files#r999249106. Otherwise, it's looking good in terms of covering the legacy undocumented behavior. Nice team work on the patch 💯

[ockham]

I've added unit test coverage for the issue discussed in the conversation starting at #3487 (comment). They're expected to fail until we settle on a resolution (see #3487 (comment)).

[gziolo]

Excellent work. Thank you addressing all my feedback. It wasn’t simple to tackle with different constraints in the REST API and in how the block type was handled in the past. In my eyes, it’s ready to land.

[ockham]

Trying to draft a commit message:

Blocks: Allow arrays for deprecated asset types in block registration.
In `register_block_type`, continue to allow passing arrays as the `editor_script`, `script`, `view_script`, `editor_style`, and `style` arguments. Note that those fields were soft-deprecated in favor of their `_handles` counterparts in [54155], which would allow specifying multiple items. At the same time, the deprecated fields were limited to `string` or `null`.
However, this broke existing code that passed an array as one of those arguments. For backwards compatibility, this change thus restores the previous behavior. It is implemented in `WP_Block_Type` as a pair of `__get()` and `__set()` methods that wrap around the corresponding `_handles` members, which are arrays of strings.
It also affects the REST API endpoint for block types. The latter’s schema has never allowed for anything other than `string` or `null` for any of those fields. For this reason, it now returns the first element of the array stored in the corresponding `_handles` member in `WP_Block_Type`.
Follow-up [54155].
Props nendeb55, costdev, gziolo, spacedmonkey, mukesh27, sergeybiryukov, audrasjb.
Fixes #56707.

[mukeshpanchal27]

Test methods with multiple assertions need a message parameter for each assertion, per Core Handbook - Writing PHPUnit Tests - Using Assertions.

[ockham]

Addressed in 9bc56a5 😊

[SergeyBiryukov]

Looks good to me 👍

[ockham]

Looks good to me 👍

Thank you very much, @SergeyBiryukov! 🎉

(I think your approval just coincided with my 9bc56a5 which I pushed to address #3487 (comment) -- not sure you saw that commit 😅 )

[SergeyBiryukov]

(I think your approval just coincided with my 9bc56a5 which I pushed to address #3487 (comment) -- not sure you saw that commit 😅 )

Looks even better now 😄

[audrasjb]

There's some coding standards issues to fix though :)

[ockham]

Merged to Core in r54670, backported to the 6.1 branch in r54671.