From 5a412611ccd59ef2d775543c868eddfcc1d93f45 Mon Sep 17 00:00:00 2001
From: Riad Benguella <benguella@gmail.com>
Date: Tue, 15 Mar 2022 13:38:24 +0100
Subject: [PATCH 1/2] Add an empty list block v2

---
 lib/compat/experimental/blocks.php          | 11 +++++++++++
 lib/experiments-page.php                    | 11 +++++++++++
 packages/block-library/src/list/index.js    |  7 ++++++-
 packages/block-library/src/list/v2/edit.js  |  5 +++++
 packages/block-library/src/list/v2/index.js | 18 ++++++++++++++++++
 packages/block-library/src/list/v2/save.js  |  5 +++++
 6 files changed, 56 insertions(+), 1 deletion(-)
 create mode 100644 packages/block-library/src/list/v2/edit.js
 create mode 100644 packages/block-library/src/list/v2/index.js
 create mode 100644 packages/block-library/src/list/v2/save.js

diff --git a/lib/compat/experimental/blocks.php b/lib/compat/experimental/blocks.php
index e0b57c663300f..657affc4aab94 100644
--- a/lib/compat/experimental/blocks.php
+++ b/lib/compat/experimental/blocks.php
@@ -159,3 +159,14 @@ function ( $response ) {
 	}
 }
 add_action( 'rest_api_init', 'gutenberg_rest_comment_set_children_as_embeddable' );
+
+/**
+ * Sets a global JS variable used to trigger the availability of the experimental list block.
+ */
+function gutenberg_enable_experimental_list_block() {
+	if ( get_option( 'gutenberg-experiments' ) && array_key_exists( 'gutenberg-list-v2', get_option( 'gutenberg-experiments' ) ) ) {
+		wp_add_inline_script( 'wp-block-library', 'window.__experimentalEnableListBlockV2 = true', 'before' );
+	}
+}
+
+add_action( 'admin_init', 'gutenberg_enable_experimental_list_block' );
diff --git a/lib/experiments-page.php b/lib/experiments-page.php
index 9421d84b88db9..f62a775d2360d 100644
--- a/lib/experiments-page.php
+++ b/lib/experiments-page.php
@@ -51,6 +51,17 @@ function gutenberg_initialize_experiments_settings() {
 			'id'    => 'gutenberg-navigation',
 		)
 	);
+	add_settings_field(
+		'gutenberg-list-v2',
+		__( 'List block v2', 'gutenberg' ),
+		'gutenberg_display_experiment_field',
+		'gutenberg-experiments',
+		'gutenberg_experiments_section',
+		array(
+			'label' => __( 'Enable List block v2 (with inner blocks)', 'gutenberg' ),
+			'id'    => 'gutenberg-list-v2',
+		)
+	);
 	register_setting(
 		'gutenberg-experiments',
 		'gutenberg-experiments'
diff --git a/packages/block-library/src/list/index.js b/packages/block-library/src/list/index.js
index 8b3e31e7cf54c..38878a4194dfa 100644
--- a/packages/block-library/src/list/index.js
+++ b/packages/block-library/src/list/index.js
@@ -11,12 +11,13 @@ import edit from './edit';
 import metadata from './block.json';
 import save from './save';
 import transforms from './transforms';
+import settingsV2 from './v2';
 
 const { name } = metadata;
 
 export { metadata, name };
 
-export const settings = {
+const settingsV1 = {
 	icon,
 	example: {
 		attributes: {
@@ -41,3 +42,7 @@ export const settings = {
 	save,
 	deprecated,
 };
+
+export const settings = window.__experimentalEnableListBlockV2
+	? settingsV2
+	: settingsV1;
diff --git a/packages/block-library/src/list/v2/edit.js b/packages/block-library/src/list/v2/edit.js
new file mode 100644
index 0000000000000..db14ebaa0427f
--- /dev/null
+++ b/packages/block-library/src/list/v2/edit.js
@@ -0,0 +1,5 @@
+function Edit() {
+	return <div>List block v2</div>;
+}
+
+export default Edit;
diff --git a/packages/block-library/src/list/v2/index.js b/packages/block-library/src/list/v2/index.js
new file mode 100644
index 0000000000000..9e96f2d40116b
--- /dev/null
+++ b/packages/block-library/src/list/v2/index.js
@@ -0,0 +1,18 @@
+/**
+ * WordPress dependencies
+ */
+import { list as icon } from '@wordpress/icons';
+
+/**
+ * Internal dependencies
+ */
+import edit from './edit';
+import save from './save';
+
+const settings = {
+	icon,
+	edit,
+	save,
+};
+
+export default settings;
diff --git a/packages/block-library/src/list/v2/save.js b/packages/block-library/src/list/v2/save.js
new file mode 100644
index 0000000000000..8970ff165f725
--- /dev/null
+++ b/packages/block-library/src/list/v2/save.js
@@ -0,0 +1,5 @@
+function Save() {
+	return <div>List block v2</div>;
+}
+
+export default Save;

From dafb9a29d89499b76577dbe0fadc8c53f560b7a3 Mon Sep 17 00:00:00 2001
From: Riad Benguella <benguella@gmail.com>
Date: Wed, 16 Mar 2022 08:36:11 +0100
Subject: [PATCH 2/2] More scary message

---
 lib/experiments-page.php                 | 2 +-
 packages/block-library/src/list/index.js | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/experiments-page.php b/lib/experiments-page.php
index f62a775d2360d..a0aabb3f3ec6b 100644
--- a/lib/experiments-page.php
+++ b/lib/experiments-page.php
@@ -58,7 +58,7 @@ function gutenberg_initialize_experiments_settings() {
 		'gutenberg-experiments',
 		'gutenberg_experiments_section',
 		array(
-			'label' => __( 'Enable List block v2 (with inner blocks)', 'gutenberg' ),
+			'label' => __( 'Test a new list block that uses nested list item blocks (Warning: The new block is not ready. You may experience content loss, avoid using it on production sites)', 'gutenberg' ),
 			'id'    => 'gutenberg-list-v2',
 		)
 	);
diff --git a/packages/block-library/src/list/index.js b/packages/block-library/src/list/index.js
index 38878a4194dfa..f107ccd332a5c 100644
--- a/packages/block-library/src/list/index.js
+++ b/packages/block-library/src/list/index.js
@@ -43,6 +43,6 @@ const settingsV1 = {
 	deprecated,
 };
 
-export const settings = window.__experimentalEnableListBlockV2
+export const settings = window?.__experimentalEnableListBlockV2
 	? settingsV2
 	: settingsV1;