Wiriting flow: Backspace at beginning of first paragraph block preven…

…ts block from being deleted (#56329)

* Writing flow: Backspace at beginning of first paragraph block prevents block from being deleted

* Use replaceBlocks

Co-authored-by: t-hamano <wildworks@git.wordpress.org>
Co-authored-by: ellatrix <ellatrix@git.wordpress.org>
Co-authored-by: draganescu <andraganescu@git.wordpress.org>

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

@@ -459,8 +459,16 @@ const applyWithDispatch = withDispatch( ( dispatch, ownProps, registry ) => {
 					}
 
 					moveFirstItemUp( rootClientId );
-				} else {
-					removeBlock( clientId );
+				} else if (
+					getBlockName( clientId ) !== getDefaultBlockName()
+				) {
+					const replacement = switchToBlockType(
+						getBlock( clientId ),
+						getDefaultBlockName()
+					);
+					if ( replacement && replacement.length ) {
+						replaceBlocks( clientId, replacement );
+					}
 				}
 			}
 		},

test/e2e/specs/editor/blocks/heading.spec.js

@@ -119,6 +119,53 @@ test.describe( 'Heading', () => {
 		] );
 	} );
 
+	test( 'should create a empty paragraph block when pressing backspace at the beginning of the first empty heading block', async ( {
+		editor,
+		page,
+	} ) => {
+		await page.keyboard.press( 'Enter' );
+		await page.keyboard.type( '## a' );
+		await page.keyboard.press( 'Backspace' );
+		await page.keyboard.press( 'Backspace' );
+
+		await expect.poll( editor.getBlocks ).toEqual( [] );
+	} );
+
+	test( 'should transform to a paragraph block when pressing backspace at the beginning of the first heading block', async ( {
+		editor,
+		page,
+	} ) => {
+		await page.keyboard.press( 'Enter' );
+		await page.keyboard.type( '## a' );
+		await page.keyboard.press( 'ArrowLeft' );
+		await page.keyboard.press( 'Backspace' );
+
+		await expect.poll( editor.getBlocks ).toMatchObject( [
+			{
+				name: 'core/paragraph',
+				attributes: { content: 'a' },
+			},
+		] );
+	} );
+
+	test( 'should keep the heading when there is an empty paragraph block before and backspace is pressed at the start', async ( {
+		editor,
+		page,
+	} ) => {
+		await page.keyboard.press( 'Enter' );
+		await page.keyboard.press( 'Enter' );
+		await page.keyboard.type( '## a' );
+		await page.keyboard.press( 'ArrowLeft' );
+		await page.keyboard.press( 'Backspace' );
+
+		await expect.poll( editor.getBlocks ).toMatchObject( [
+			{
+				name: 'core/heading',
+				attributes: { content: 'a', level: 2 },
+			},
+		] );
+	} );
+
 	test( 'should correctly apply custom colors', async ( {
 		editor,
 		page,