add support for __experimentalSkiSerialization to the shadow attribute

[colinduwe]

What?
This is a backport of the merged Gutenberg PR WordPress/gutenberg#59887
When a dynamic block defines __experimentalSkipSerialization in its block.supports.shadow the styles continue to be printed to the block wrapper element. This PR corrects that behavior so that shadow behaves like border, color, and others.
Why?
This provides the expected behavior for dynamic blocks that need to opt out of having the shadow styles printed to the block wrapper.
How?
Added a check at the start of the render function to return an empty array if the block has set __experimentalSkipSerialization

(This is my first attempt at submitting a Gutenberg PR to be included back into WP Core so welcome any advice if I'm doing this wrong)

Trac ticket: https://core.trac.wordpress.org/ticket/60784#ticket

---

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[aaronrobertshaw]

Thanks for backporting this fix @colinduwe 👍

The change here matches WordPress/gutenberg#59887.

I was going to note that we should add a unit test for this but it appears no tests have been added for the shadow block support like there are for typography, border etc.

@madhusudhand are you aware of any PRs in progress adding unit tests for the shadow support?

While this does allow support for an experimental block.json property (that should be stabilized soon), it does make the shadow block support consistent with all others while only introducing a call to a stable core function. I'd like to see this land.

[madhusudhand]

@madhusudhand are you aware of any PRs in progress adding unit tests for the shadow support?

I have created WordPress/gutenberg#60063 which tests these changes.

[vcanales]

👋 @colinduwe @madhusudhand what is the status here?

It looks like WordPress/gutenberg#60063 has been approved. Are you facing any blockers?

[colinduwe]

@vcanales I think it is probably only blocked by my ignorance of the process here. I thought this was merely awaiting approval from someone with commit access.

[aaronrobertshaw]

It looks like WordPress/gutenberg#60063 has been approved. Are you facing any blockers?

Once WordPress/gutenberg#60063 is merged, this should probably also include the unit test the code change relates to.

[madhusudhand]

@colinduwe could you bring the unit tests from WordPress/gutenberg#60063 into this?

[colinduwe]

@madhusudhand I think I'm out of my depth here. I'm not sure how to do that.

[madhusudhand]

@colinduwe I have created #6613 with the unit tests.
Please checkout #6613 to a branch and cherry pick the commit 8a46596 into this PR

git fetch origin pull/6613/head:shadow-unit-tests
git cherry-pick 8a4659608ba43363b4bd63fd76e99635c55141c8

[colinduwe]

Your're a hero @madhusudhand. Thanks. Done.

[vcanales]

Thanks for bringing in the tests!

We have to rename the functions, since the gutenberg_ prefix is meant to be used within Gutenberg and not core (https://github.com/WordPress/wordpress-develop/pull/6279/files#diff-a903d994435db8240aed96e253cfb2097ecbe9705d6f88ecdfd441422ecf2da3R52)

Suggested change

	public function test_gutenberg_apply_shadow_support( $support, $value, $expected ) {
	$block_type = self::register_shadow_block_with_support(
	'test/shadow-block',
	array( 'shadow' => $support )
	);
	$block_attrs = array( 'style' => array( 'shadow' => $value ) );
	$actual = gutenberg_apply_shadow_support( $block_type, $block_attrs );
	public function test_wp_apply_shadow_support( $support, $value, $expected ) {
	$block_type = self::register_shadow_block_with_support(
	'test/shadow-block',
	array( 'shadow' => $support )
	);
	$block_attrs = array( 'style' => array( 'shadow' => $value ) );
	$actual = wp_apply_shadow_support( $block_type, $block_attrs );

[madhusudhand]

Fixed here.

@colinduwe please pull and
git cherry-pick 5383012d66abb19d39388750fd3e1b46ec0d60b6

[colinduwe]

Done

[tellthemachines]

Would be good to add a since note to the docblock above; something like

@since 6.6.0 Return early if __experimentalSkipSerialization is true.

(it should be added just below @since 6.3.0)

[tellthemachines]

Thanks for updating @colinduwe, LGTM!

[tellthemachines]

Committed in r58312.

[mukeshpanchal27]

@tellthemachines why the ticket number is not mention for test?

[tellthemachines]

Thanks for spotting that! Fixed in https://core.trac.wordpress.org/changeset/58315.