Blocks: Deprecate non-string descriptions

packages/blocks/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+### Deprecations
+
+-   Deprecate non-string descriptions ([#44455](https://github.com/WordPress/gutenberg/pull/44455)).
+
 ## 11.17.0 (2022-09-21)
 
 - The block attribute sources `children` and `node` have been deprecated. Please use the `html` source instead. See https://developer.wordpress.org/block-editor/how-to-guides/block-tutorial/introducing-attributes-and-editable-fields/ and the core blocks for examples.

packages/blocks/src/api/test/registration.js

@@ -4,6 +4,7 @@
  * WordPress dependencies
  */
 import { addFilter, removeAllFilters, removeFilter } from '@wordpress/hooks';
+import { logged } from '@wordpress/deprecated';
 import { select } from '@wordpress/data';
 
 /**
@@ -61,6 +62,11 @@ describe( 'blocks', () => {
 		setUnregisteredTypeHandlerName( undefined );
 		setDefaultBlockName( undefined );
 		unstable__bootstrapServerSideBlockDefinitions( {} );
+
+		// Reset deprecation logging to ensure we properly track warnings.
+		for ( const key in logged ) {
+			delete logged[ key ];
+		}
 	} );
 
 	describe( 'registerBlockType()', () => {
@@ -832,6 +838,41 @@ describe( 'blocks', () => {
 				// Only attributes of block1 are supposed to be edited by the filter thus it must differ from block2.
 				expect( block1.attributes ).not.toEqual( block2.attributes );
 			} );
+
+			it( 'should allow non-string descriptions at registration but warn for undesired usage.', () => {
+				const newDescription = <p>foo bar</p>;
+
+				const block = registerBlockType( 'my-plugin/test-block-1', {
+					...defaultBlockSettings,
+					description: newDescription,
+				} );
+
+				expect( block.description ).toBe( newDescription );
+				expect( console ).toHaveWarnedWith(
+					'Declaring non-string block descriptions is deprecated since version 6.2.'
+				);
+			} );
+
+			it( 'should allow non-string descriptions through `blocks.registerBlockType` filter but warn for undesired usage.', () => {
+				const newDescription = <p>foo bar</p>;
+				addFilter(
+					'blocks.registerBlockType',
+					'core/blocks/non-string-description',
+					( settings ) => {
+						settings.description = newDescription;
+						return settings;
+					}
+				);
+				const block = registerBlockType(
+					'my-plugin/test-block-2',
+					defaultBlockSettings
+				);
+
+				expect( block.description ).toBe( newDescription );
+				expect( console ).toHaveWarnedWith(
+					'Declaring non-string block descriptions is deprecated since version 6.2.'
+				);
+			} );
 		} );
 
 		test( 'registers block from metadata', () => {

packages/blocks/src/store/actions.js

@@ -7,6 +7,7 @@ import { castArray, pick, some } from 'lodash';
 /**
  * WordPress dependencies
  */
+import deprecated from '@wordpress/deprecated';
 import { applyFilters } from '@wordpress/hooks';
 
 /**
@@ -63,6 +64,12 @@ const processBlockType = ( blockType, { select } ) => {
 		null
 	);
 
+	if ( settings.description && typeof settings.description !== 'string' ) {
+		deprecated( 'Declaring non-string block descriptions', {
+			since: '6.2',
+		} );
+	}
+
 	if ( settings.deprecated ) {
 		settings.deprecated = settings.deprecated.map( ( deprecation ) =>
 			pick(