Reusable Blocks: Preload user permissions

lib/client-assets.php

@@ -560,3 +560,32 @@ function gutenberg_extend_block_editor_styles( $settings ) {
 	return $settings;
 }
 add_filter( 'block_editor_settings', 'gutenberg_extend_block_editor_styles' );
+
+/**
+ * Extends block editor preload paths to preload additional data. Note that any
+ * additions here should be complemented with a corresponding core ticket to
+ * reconcile the change upstream for future removal from Gutenberg.
+ *
+ * @since 5.6.0
+ *
+ * @param array $preload_paths $preload_paths Array of paths to preload.
+ *
+ * @return array Filtered array of paths to preload.
+ */
+function gutenberg_extend_block_editor_preload_paths( $preload_paths ) {
+	/*
+	 * Used in considering user permissions for creating and updating blocks,
+	 * as condition for displaying relevant actions in the interface.
+	 *
+	 * Trac ticket: https://core.trac.wordpress.org/ticket/46429
+	 *
+	 * This is present in WordPress 5.2 and should be removed from Gutenberg
+	 * once WordPress 5.2 is the minimum supported version.
+	 */
+	if ( ! in_array( array( '/wp/v2/blocks', 'OPTIONS' ), $preload_paths ) ) {
+		$preload_paths[] = array( '/wp/v2/blocks', 'OPTIONS' );
+	}
+
+	return $preload_paths;
+}
+add_filter( 'block_editor_preload_paths', 'gutenberg_extend_block_editor_preload_paths' );

packages/e2e-tests/specs/block-deletion.test.js

@@ -30,7 +30,7 @@ describe( 'block deletion -', () => {
 	beforeEach( addThreeParagraphsToNewPost );
 
 	describe( 'deleting the third block using the Remove Block menu item', () => {
-		it.skip( 'results in two remaining blocks and positions the caret at the end of the second block', async () => {
+		it( 'results in two remaining blocks and positions the caret at the end of the second block', async () => {
 			// The blocks can't be empty to trigger the toolbar
 			await page.keyboard.type( 'Paragraph to remove' );
 

phpunit/class-extend-preload-paths-test.php

@@ -0,0 +1,26 @@
+<?php
+/**
+ * Test `gutenberg_extend_block_editor_preload_paths`.
+ *
+ * @package Gutenberg
+ */
+
+class Extend_Preload_Paths_Test extends WP_UnitTestCase {
+	/**
+	 * Tests '/wp/v2/blocks' added if missing.
+	 */
+	function test_localizes_script() {
+		$preload_paths = gutenberg_extend_block_editor_preload_paths( array() );
+
+		$this->assertEquals( array( array( '/wp/v2/blocks', 'OPTIONS' ) ), $preload_paths );
+	}
+
+	/**
+	 * Tests '/wp/v2/blocks' not added if present.
+	 */
+	function test_replaces_registered_properties() {
+		$preload_paths = gutenberg_extend_block_editor_preload_paths( array( array( '/wp/v2/blocks', 'OPTIONS' ) ) );
+
+		$this->assertEquals( array( array( '/wp/v2/blocks', 'OPTIONS' ) ), $preload_paths );
+	}
+}