From eb77e48d27d16f6f82925fe4d06a76b62f33f572 Mon Sep 17 00:00:00 2001
From: Ella <4710635+ellatrix@users.noreply.github.com>
Date: Mon, 9 Oct 2023 20:27:09 +0300
Subject: [PATCH] Writing flow: preserve block when merging into empty
 paragraph (#55134)

---
 .../src/components/block-list/block.js        |  2 ++
 .../src/components/rich-text/use-delete.js    |  2 +-
 packages/block-editor/src/store/actions.js    | 33 ++++++++++++++-----
 3 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/packages/block-editor/src/components/block-list/block.js b/packages/block-editor/src/components/block-list/block.js
index 4bf9bb634dbf6..a95075c6f9b42 100644
--- a/packages/block-editor/src/components/block-list/block.js
+++ b/packages/block-editor/src/components/block-list/block.js
@@ -494,6 +494,8 @@ const applyWithDispatch = withDispatch( ( dispatch, ownProps, registry ) => {
 					}
 
 					moveFirstItemUp( rootClientId );
+				} else {
+					removeBlock( clientId );
 				}
 			}
 		},
diff --git a/packages/block-editor/src/components/rich-text/use-delete.js b/packages/block-editor/src/components/rich-text/use-delete.js
index f09a15265bd2b..fbf025a5d4ea4 100644
--- a/packages/block-editor/src/components/rich-text/use-delete.js
+++ b/packages/block-editor/src/components/rich-text/use-delete.js
@@ -43,7 +43,7 @@ export function useDelete( props ) {
 				// an intentional user interaction distinguishing between Backspace and
 				// Delete to remove the empty field, but also to avoid merge & remove
 				// causing destruction of two fields (merge, then removed merged).
-				if ( onRemove && isEmpty( value ) && isReverse ) {
+				else if ( onRemove && isEmpty( value ) && isReverse ) {
 					onRemove( ! isReverse );
 				}
 
diff --git a/packages/block-editor/src/store/actions.js b/packages/block-editor/src/store/actions.js
index ae4b64a645d3e..2975a41dbb9d9 100644
--- a/packages/block-editor/src/store/actions.js
+++ b/packages/block-editor/src/store/actions.js
@@ -13,6 +13,7 @@ import {
 	switchToBlockType,
 	synchronizeBlocksWithTemplate,
 	getBlockSupport,
+	isUnmodifiedDefaultBlock,
 } from '@wordpress/blocks';
 import { speak } from '@wordpress/a11y';
 import { __, _n, sprintf } from '@wordpress/i18n';
@@ -1013,17 +1014,12 @@ export const mergeBlocks =
 
 		if ( ! blockAType ) return;
 
+		const blockB = select.getBlock( clientIdB );
+
 		if (
 			! blockAType.merge &&
-			! getBlockSupport( blockA.name, '__experimentalOnMerge' )
+			getBlockSupport( blockA.name, '__experimentalOnMerge' )
 		) {
-			dispatch.selectBlock( blockA.clientId );
-			return;
-		}
-
-		const blockB = select.getBlock( clientIdB );
-
-		if ( ! blockAType.merge ) {
 			// If there's no merge function defined, attempt merging inner
 			// blocks.
 			const blocksWithTheSameType = switchToBlockType(
@@ -1090,6 +1086,27 @@ export const mergeBlocks =
 			return;
 		}
 
+		if ( isUnmodifiedDefaultBlock( blockA ) ) {
+			dispatch.removeBlock(
+				clientIdA,
+				select.isBlockSelected( clientIdA )
+			);
+			return;
+		}
+
+		if ( isUnmodifiedDefaultBlock( blockB ) ) {
+			dispatch.removeBlock(
+				clientIdB,
+				select.isBlockSelected( clientIdB )
+			);
+			return;
+		}
+
+		if ( ! blockAType.merge ) {
+			dispatch.selectBlock( blockA.clientId );
+			return;
+		}
+
 		const blockBType = getBlockType( blockB.name );
 		const { clientId, attributeKey, offset } = select.getSelectionStart();
 		const selectedBlockType =