Block API: Use an extension to ensure matchers' backwards compatibiliy

blocks/api/index.js

@@ -16,6 +16,3 @@ export {
 	hasBlockSupport,
 } from './registration';
 
-// Deprecated matchers
-import * as source from './source';
-export { source };

blocks/api/registration.js

@@ -3,7 +3,7 @@
 /**
  * External dependencies
  */
-import { get, isFunction, some, mapValues } from 'lodash';
+import { get, isFunction, some } from 'lodash';
 
 /**
  * WordPress dependencies
@@ -119,17 +119,6 @@ export function registerBlockType( name, settings ) {
 		...settings,
 	};
 
-	// Resolve deprecated attributes
-	settings.attributes = mapValues( settings.attributes, ( attribute ) => {
-		if ( isFunction( attribute.source ) ) {
-			return {
-				...attribute,
-				...attribute.source(),
-			};
-		}
-		return attribute;
-	} );
-
 	settings = applyFilters( 'registerBlockType', settings, name );
 
 	return blocks[ name ] = settings;

blocks/hooks/index.js

@@ -8,6 +8,7 @@ import createHooks from '@wordpress/hooks';
  */
 import anchor from './anchor';
 import customClassName from './custom-class-name';
+import matchers from './matchers';
 
 const hooks = createHooks();
 
@@ -47,3 +48,4 @@ export {
 
 anchor( hooks );
 customClassName( hooks );
+matchers( hooks );

blocks/api/source.js → blocks/hooks/matchers.js

@@ -1,3 +1,8 @@
+/**
+ * External dependencies
+ */
+import { isFunction, mapValues } from 'lodash';
+
 function warnAboutDeprecatedMatcher() {
 	// eslint-disable-next-line no-console
 	console.warn(
@@ -64,3 +69,28 @@ export const node = ( selector ) => () => {
 		selector,
 	};
 };
+
+/**
+ * Resolve the matchers attributes for backwards compatibilty
+ *
+ * @param  {Object} settings Original block settings
+ * @return {Object}          Filtered block settings
+ */
+export function resolveAttributes( settings ) {
+	// Resolve deprecated attributes
+	settings.attributes = mapValues( settings.attributes, ( attribute ) => {
+		if ( isFunction( attribute.source ) ) {
+			return {
+				...attribute,
+				...attribute.source(),
+			};
+		}
+		return attribute;
+	} );
+
+	return settings;
+}
+
+export default function anchor( { addFilter } ) {
+	addFilter( 'registerBlockType', 'core\matchers', resolveAttributes );
+}

blocks/index.js

@@ -27,3 +27,7 @@ export { default as InspectorControls } from './inspector-controls';
 export { default as MediaUploadButton } from './media-upload-button';
 export { default as UrlInput } from './url-input';
 export { default as UrlInputButton } from './url-input/button';
+
+// Deprecated matchers
+import { attr, prop, text, html, query, node, children } from './hooks/matchers';
+export const source = { attr, prop, text, html, query, node, children };