Editor: Shim meta attributes for early block registrations

packages/e2e-tests/plugins/meta-attribute-block.php

@@ -29,13 +29,23 @@ function init_test_meta_attribute_block_plugin() {
  */
 function enqueue_test_meta_attribute_block() {
 	wp_enqueue_script(
-		'gutenberg-test-meta-attribute-block',
-		plugins_url( 'meta-attribute-block/index.js', __FILE__ ),
+		'gutenberg-test-meta-attribute-block-early',
+		plugins_url( 'meta-attribute-block/early.js', __FILE__ ),
 		array(
 			'wp-blocks',
 			'wp-element',
 		),
-		filemtime( plugin_dir_path( __FILE__ ) . 'meta-attribute-block/index.js' ),
+		filemtime( plugin_dir_path( __FILE__ ) . 'meta-attribute-block/early.js' )
+	);
+
+	wp_enqueue_script(
+		'gutenberg-test-meta-attribute-block-late',
+		plugins_url( 'meta-attribute-block/late.js', __FILE__ ),
+		array(
+			'wp-blocks',
+			'wp-element',
+		),
+		filemtime( plugin_dir_path( __FILE__ ) . 'meta-attribute-block/late.js' ),
 		true
 	);
 }

packages/e2e-tests/plugins/meta-attribute-block/early.js

@@ -0,0 +1,32 @@
+( function() {
+	var registerBlockType = wp.blocks.registerBlockType;
+	var el = wp.element.createElement;
+
+	registerBlockType( 'test/test-meta-attribute-block-early', {
+		title: 'Test Meta Attribute Block (Early Registration)',
+		icon: 'star',
+		category: 'common',
+
+		attributes: {
+			content: {
+				type: 'string',
+				source: 'meta',
+				meta: 'my_meta',
+			},
+		},
+
+		edit: function( props ) {
+			return el( 'input', {
+				className: 'my-meta-input',
+				value: props.attributes.content,
+				onChange: function( event ) {
+					props.setAttributes( { content: event.target.value } );
+				},
+			} );
+		},
+
+		save: function() {
+			return null;
+		},
+	} );
+} )();

packages/e2e-tests/plugins/meta-attribute-block/late.js

@@ -0,0 +1,32 @@
+( function() {
+	var registerBlockType = wp.blocks.registerBlockType;
+	var el = wp.element.createElement;
+
+	registerBlockType( 'test/test-meta-attribute-block-late', {
+		title: 'Test Meta Attribute Block (Late Registration)',
+		icon: 'star',
+		category: 'common',
+
+		attributes: {
+			content: {
+				type: 'string',
+				source: 'meta',
+				meta: 'my_meta',
+			},
+		},
+
+		edit: function( props ) {
+			return el( 'input', {
+				className: 'my-meta-input',
+				value: props.attributes.content,
+				onChange: function( event ) {
+					props.setAttributes( { content: event.target.value } );
+				},
+			} );
+		},
+
+		save: function() {
+			return null;
+		},
+	} );
+} )();

packages/e2e-tests/specs/editor/plugins/__snapshots__/meta-attribute-block.test.js.snap

@@ -1,5 +1,9 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
-exports[`Block with a meta attribute Should persist the meta attribute properly 1`] = `"<!-- wp:test/test-meta-attribute-block /-->"`;
+exports[`Block with a meta attribute Early Registration Should persist the meta attribute properly 1`] = `"<!-- wp:test/test-meta-attribute-block-early /-->"`;
 
-exports[`Block with a meta attribute Should persist the meta attribute properly in a different post type 1`] = `"<!-- wp:test/test-meta-attribute-block /-->"`;
+exports[`Block with a meta attribute Early Registration Should persist the meta attribute properly in a different post type 1`] = `"<!-- wp:test/test-meta-attribute-block-early /-->"`;
+
+exports[`Block with a meta attribute Late Registration Should persist the meta attribute properly 1`] = `"<!-- wp:test/test-meta-attribute-block-late /-->"`;
+
+exports[`Block with a meta attribute Late Registration Should persist the meta attribute properly in a different post type 1`] = `"<!-- wp:test/test-meta-attribute-block-late /-->"`;

packages/e2e-tests/specs/editor/plugins/meta-attribute-block.test.js

@@ -24,68 +24,75 @@ describe( 'Block with a meta attribute', () => {
 		await deactivatePlugin( 'gutenberg-test-meta-attribute-block' );
 	} );
 
-	it( 'Should persist the meta attribute properly', async () => {
-		await insertBlock( 'Test Meta Attribute Block' );
-		await page.keyboard.type( 'Value' );
+	describe.each( [ [ 'Early Registration' ], [ 'Late Registration' ] ] )(
+		'%s',
+		( variant ) => {
+			it( 'Should persist the meta attribute properly', async () => {
+				await insertBlock( `Test Meta Attribute Block (${ variant })` );
+				await page.keyboard.type( 'Value' );
 
-		// Regression Test: Previously the caret would wrongly reset to the end
-		// of any input for meta-sourced attributes, due to syncing behavior of
-		// meta attribute updates.
-		//
-		// See: https://github.com/WordPress/gutenberg/issues/15739
-		await pressKeyTimes( 'ArrowLeft', 5 );
-		await page.keyboard.type( 'Meta ' );
+				// Regression Test: Previously the caret would wrongly reset to the end
+				// of any input for meta-sourced attributes, due to syncing behavior of
+				// meta attribute updates.
+				//
+				// See: https://github.com/WordPress/gutenberg/issues/15739
+				await pressKeyTimes( 'ArrowLeft', 5 );
+				await page.keyboard.type( 'Meta ' );
 
-		await saveDraft();
-		await page.reload();
+				await saveDraft();
+				await page.reload();
 
-		expect( await getEditedPostContent() ).toMatchSnapshot();
-		const persistedValue = await page.evaluate(
-			() => document.querySelector( '.my-meta-input' ).value
-		);
-		expect( persistedValue ).toBe( 'Meta Value' );
-	} );
+				expect( await getEditedPostContent() ).toMatchSnapshot();
+				const persistedValue = await page.evaluate(
+					() => document.querySelector( '.my-meta-input' ).value
+				);
+				expect( persistedValue ).toBe( 'Meta Value' );
+			} );
 
-	it( 'Should use the same value in all the blocks', async () => {
-		await insertBlock( 'Test Meta Attribute Block' );
-		await insertBlock( 'Test Meta Attribute Block' );
-		await insertBlock( 'Test Meta Attribute Block' );
-		await page.keyboard.type( 'Meta Value' );
+			it( 'Should use the same value in all the blocks', async () => {
+				await insertBlock( `Test Meta Attribute Block (${ variant })` );
+				await insertBlock( `Test Meta Attribute Block (${ variant })` );
+				await insertBlock( `Test Meta Attribute Block (${ variant })` );
+				await page.keyboard.type( 'Meta Value' );
 
-		const inputs = await page.$$( '.my-meta-input' );
-		await Promise.all(
-			inputs.map( async ( input ) => {
-				// Clicking the input selects the block,
-				// and selecting the block enables the sync data mode
-				// as otherwise the asynchronous re-rendering of unselected blocks
-				// may cause the input to have not yet been updated for the other blocks
-				await input.click();
-				const inputValue = await input.getProperty( 'value' );
-				expect( await inputValue.jsonValue() ).toBe( 'Meta Value' );
-			} )
-		);
-	} );
+				const inputs = await page.$$( '.my-meta-input' );
+				await Promise.all(
+					inputs.map( async ( input ) => {
+						// Clicking the input selects the block,
+						// and selecting the block enables the sync data mode
+						// as otherwise the asynchronous re-rendering of unselected blocks
+						// may cause the input to have not yet been updated for the other blocks
+						await input.click();
+						const inputValue = await input.getProperty( 'value' );
+						expect( await inputValue.jsonValue() ).toBe(
+							'Meta Value'
+						);
+					} )
+				);
+			} );
 
-	it( 'Should persist the meta attribute properly in a different post type', async () => {
-		await createNewPost( { postType: 'page' } );
-		await insertBlock( 'Test Meta Attribute Block' );
-		await page.keyboard.type( 'Value' );
+			it( 'Should persist the meta attribute properly in a different post type', async () => {
+				await createNewPost( { postType: 'page' } );
+				await insertBlock( `Test Meta Attribute Block (${ variant })` );
+				await page.keyboard.type( 'Value' );
 
-		// Regression Test: Previously the caret would wrongly reset to the end
-		// of any input for meta-sourced attributes, due to syncing behavior of
-		// meta attribute updates.
-		//
-		// See: https://github.com/WordPress/gutenberg/issues/15739
-		await pressKeyTimes( 'ArrowLeft', 5 );
-		await page.keyboard.type( 'Meta ' );
+				// Regression Test: Previously the caret would wrongly reset to the end
+				// of any input for meta-sourced attributes, due to syncing behavior of
+				// meta attribute updates.
+				//
+				// See: https://github.com/WordPress/gutenberg/issues/15739
+				await pressKeyTimes( 'ArrowLeft', 5 );
+				await page.keyboard.type( 'Meta ' );
 
-		await saveDraft();
-		await page.reload();
+				await saveDraft();
+				await page.reload();
 
-		expect( await getEditedPostContent() ).toMatchSnapshot();
-		const persistedValue = await page.evaluate(
-			() => document.querySelector( '.my-meta-input' ).value
-		);
-		expect( persistedValue ).toBe( 'Meta Value' );
-	} );
+				expect( await getEditedPostContent() ).toMatchSnapshot();
+				const persistedValue = await page.evaluate(
+					() => document.querySelector( '.my-meta-input' ).value
+				);
+				expect( persistedValue ).toBe( 'Meta Value' );
+			} );
+		}
+	);
 } );

packages/editor/src/hooks/custom-sources-backwards-compatibility.js

@@ -6,7 +6,7 @@ import { pickBy, mapValues, isEmpty, mapKeys } from 'lodash';
 /**
  * WordPress dependencies
  */
-import { useSelect } from '@wordpress/data';
+import { select as globalSelect, useSelect } from '@wordpress/data';
 import { useEntityProp } from '@wordpress/core-data';
 import { useMemo } from '@wordpress/element';
 import { createHigherOrderComponent } from '@wordpress/compose';
@@ -116,3 +116,26 @@ addFilter(
 	'core/editor/custom-sources-backwards-compatibility/shim-attribute-source',
 	shimAttributeSource
 );
+
+// The above filter will only capture blocks registered after the filter was
+// added. There may already be blocks registered by this point, and those must
+// be updated to apply the shim.
+//
+// The following implementation achieves this, albeit with a couple caveats:
+// - Only blocks registered on the global store will be modified.
+// - The block settings are directly mutated, since there is currently no
+//   mechanism to update an existing block registration. This is the reason for
+//   `getBlockType` separate from `getBlockTypes`, since the latter returns a
+//   _copy_ of the block registration (i.e. the mutation would not affect the
+//   actual registered block settings).
+//
+// `getBlockTypes` or `getBlockType` implementation could change in the future
+// in regards to creating settings clones, but the corresponding end-to-end
+// tests for meta blocks should cover against any potential regressions.
+//
+// In the future, we could support updating block settings, at which point this
+// implementation could use that mechanism instead.
+globalSelect( 'core/blocks' )
+	.getBlockTypes()
+	.map( ( { name } ) => globalSelect( 'core/blocks' ).getBlockType( name ) )
+	.forEach( shimAttributeSource );