Convert it to a separate util

packages/block-editor/src/components/block-list/block.js

@@ -26,6 +26,7 @@ import {
 	hasBlockSupport,
 	__experimentalGetBlockAttributesNamesByRole,
 	store as blocksStore,
+	privateApis as blocksPrivateApis,
 } from '@wordpress/blocks';
 import { withFilters } from '@wordpress/components';
 import { withDispatch, useDispatch, useSelect } from '@wordpress/data';
@@ -47,6 +48,8 @@ import { PrivateBlockContext } from './private-block-context';
 
 import { unlock } from '../../lock-unlock';
 
+const { isAttributeUnmodified } = unlock( blocksPrivateApis );
+
 /**
  * Merges wrapper props with special handling for classNames and styles.
  *
@@ -336,16 +339,18 @@ const applyWithDispatch = withDispatch( ( dispatch, ownProps, registry ) => {
 			 * @return {boolean} Whether the block content is empty.
 			 */
 			function isBlockContentEmpty( blockClientId ) {
-				const blockName = getBlockName( blockClientId );
+				const block = getBlock( blockClientId );
+				const blockType = getBlockType( block.name );
 				const contentAttributes =
 					__experimentalGetBlockAttributesNamesByRole(
-						blockName,
+						block.name,
 						'content'
 					);
-				return isUnmodifiedBlock(
-					getBlock( blockClientId ),
-					contentAttributes
-				);
+				return contentAttributes.every( ( key ) => {
+					const value = block.attributes[ key ];
+					const definition = blockType.attributes[ key ];
+					return isAttributeUnmodified( definition, value );
+				} );
 			}
 
 			/**
@@ -375,6 +380,8 @@ const applyWithDispatch = withDispatch( ( dispatch, ownProps, registry ) => {
 								targetRootClientId
 							) &&
 							// Don't move the block if its content is considered empty.
+							// Note that for a modified non-empty block, we still try to transform
+							// it to a default block.
 							// Fix for https://github.com/WordPress/gutenberg/issues/65174.
 							! isBlockContentEmpty( firstClientId )
 						) {

packages/blocks/README.md

@@ -355,7 +355,6 @@ Determines whether the block's attributes are equal to the default attributes wh
 _Parameters_
 
 -   _block_ `WPBlock`: Block Object
--   _attributeKeys_ `?string[]`: The optional keys of the attributes to check.
 
 _Returns_
 

packages/blocks/src/api/index.js

@@ -8,6 +8,7 @@ import {
 	getBlockBindingsSource,
 	getBlockBindingsSources,
 } from './registration';
+import { isAttributeUnmodified } from './utils';
 
 // The blocktype is the most important concept within the block API. It defines
 // all aspects of the block configuration and its interfaces, including `edit`
@@ -182,4 +183,5 @@ lock( privateApis, {
 	unregisterBlockBindingsSource,
 	getBlockBindingsSource,
 	getBlockBindingsSources,
+	isAttributeUnmodified,
 } );

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

@@ -9,12 +9,12 @@ import {
 	setDefaultBlockName,
 } from '../registration';
 import {
-	isUnmodifiedBlock,
 	isUnmodifiedDefaultBlock,
 	getAccessibleBlockLabel,
 	getBlockLabel,
 	__experimentalSanitizeBlockAttributes,
 	__experimentalGetBlockAttributesNamesByRole,
+	isAttributeUnmodified,
 } from '../utils';
 
 const noop = () => {};
@@ -398,37 +398,53 @@ describe( '__experimentalGetBlockAttributesNamesByRole', () => {
 	} );
 } );
 
-describe( 'isUnmodifiedBlock', () => {
-	beforeAll( () => {
-		registerBlockType( 'core/test-block', {
-			title: 'Test block',
-			attributes: {
-				content: {
-					type: 'rich-text',
-					__experimentalRole: 'content',
-				},
-				placeholder: { type: 'rich-text' },
-			},
-		} );
-	} );
-
-	afterAll( () => {
-		unregisterBlockType( 'core/test-block' );
-	} );
-
+describe( 'isAttributeUnmodified', () => {
 	it( 'should return true if the block is unmodified', () => {
-		const block = createBlock( 'core/test-block' );
-		expect( isUnmodifiedBlock( block ) ).toBe( true );
-
-		block.attributes.content = 'modified';
-		expect( isUnmodifiedBlock( block ) ).toBe( false );
+		expect(
+			isAttributeUnmodified(
+				{ type: 'rich-text', __experimentalRole: 'content' },
+				''
+			)
+		).toBe( true );
+		expect(
+			isAttributeUnmodified(
+				{ type: 'rich-text', __experimentalRole: 'content' },
+				undefined
+			)
+		).toBe( true );
+		expect( isAttributeUnmodified( { type: 'string' }, undefined ) ).toBe(
+			true
+		);
+		expect(
+			isAttributeUnmodified(
+				{ type: 'string', default: 'default-value' },
+				'default-value'
+			)
+		).toBe( true );
 	} );
 
-	it( 'should only check the attribute keys', () => {
-		const block = createBlock( 'core/test-block', {
-			placeholder: 'Type here...',
-		} );
-		expect( isUnmodifiedBlock( block ) ).toBe( false );
-		expect( isUnmodifiedBlock( block, [ 'content' ] ) ).toBe( true );
+	it( 'should return false if the block is modified', () => {
+		expect(
+			isAttributeUnmodified(
+				{ type: 'rich-text', __experimentalRole: 'content' },
+				'something else'
+			)
+		).toBe( false );
+		expect(
+			isAttributeUnmodified( { type: 'string' }, 'something else' )
+		).toBe( false );
+		expect( isAttributeUnmodified( { type: 'string' }, '' ) ).toBe( false );
+		expect(
+			isAttributeUnmodified(
+				{ type: 'string', default: 'default-value' },
+				''
+			)
+		).toBe( false );
+		expect(
+			isAttributeUnmodified(
+				{ type: 'string', default: 'default-value' },
+				undefined
+			)
+		).toBe( false );
 	} );
 } );

packages/blocks/src/api/utils.js

@@ -29,42 +29,46 @@ extend( [ namesPlugin, a11yPlugin ] );
  */
 const ICON_COLORS = [ '#191e23', '#f8f9f9' ];
 
+/**
+ * Determines whether the block's attribute is equal to the default attribute
+ * which means the attribute is unmodified.
+ * @param {Object} attributeDefinition The attribute's definition of the block type.
+ * @param {*}      value               The attribute's value.
+ * @return {boolean} Whether the attribute is unmodified.
+ */
+export function isAttributeUnmodified( attributeDefinition, value ) {
+	// Every attribute that has a default must match the default.
+	if ( attributeDefinition.hasOwnProperty( 'default' ) ) {
+		return value === attributeDefinition.default;
+	}
+
+	// The rich text type is a bit different from the rest because it
+	// has an implicit default value of an empty RichTextData instance,
+	// so check the length of the value.
+	if ( attributeDefinition.type === 'rich-text' ) {
+		return ! value?.length;
+	}
+
+	// Every attribute that doesn't have a default should be undefined.
+	return value === undefined;
+}
+
 /**
  * Determines whether the block's attributes are equal to the default attributes
  * which means the block is unmodified.
  *
- * @param {WPBlock}   block         Block Object
- * @param {?string[]} attributeKeys The optional keys of the attributes to check.
+ * @param {WPBlock} block Block Object
  *
  * @return {boolean} Whether the block is an unmodified block.
  */
-export function isUnmodifiedBlock( block, attributeKeys ) {
-	let attributeEntries = Object.entries(
-		getBlockType( block.name )?.attributes ?? {}
-	);
-	if ( attributeKeys ) {
-		attributeEntries = attributeEntries.filter( ( [ key ] ) =>
-			attributeKeys.includes( key )
-		);
-	}
-	return attributeEntries.every( ( [ key, definition ] ) => {
-		const value = block.attributes[ key ];
+export function isUnmodifiedBlock( block ) {
+	return Object.entries( getBlockType( block.name )?.attributes ?? {} ).every(
+		( [ key, definition ] ) => {
+			const value = block.attributes[ key ];
 
-		// Every attribute that has a default must match the default.
-		if ( definition.hasOwnProperty( 'default' ) ) {
-			return value === definition.default;
+			return isAttributeUnmodified( definition, value );
 		}
-
-		// The rich text type is a bit different from the rest because it
-		// has an implicit default value of an empty RichTextData instance,
-		// so check the length of the value.
-		if ( definition.type === 'rich-text' ) {
-			return ! value?.length;
-		}
-
-		// Every attribute that doesn't have a default should be undefined.
-		return value === undefined;
-	} );
+	);
 }
 
 /**

test/e2e/specs/editor/various/splitting-merging.spec.js

@@ -421,12 +421,12 @@ test.describe( 'splitting and merging blocks (@firefox, @webkit)', () => {
 				},
 			] );
 
-		// Move the caret is moved to the beginning of the heading block.
+		// Move the caret to the beginning of the heading block.
 		await page.keyboard.press( 'Backspace' );
 		await expect
 			.poll(
 				editor.getBlocks,
-				'Pressing backspace should transform the non-default empty block'
+				'Pressing backspace should still transform the empty block'
 			)
 			.toMatchObject( [
 				{