From f12b78b7c4e830032d7f9a4641df40236644683b Mon Sep 17 00:00:00 2001
From: Aki Hamano <54422211+t-hamano@users.noreply.github.com>
Date: Tue, 6 Aug 2024 17:22:39 +0900
Subject: [PATCH] Drag & Drop: Fix unexpected row/galley creation logic
 (#64241)

* Drag & Drop: Fix unexpected row/galley creation logic

* Add comment

* Remove function that checks if a row or gallery can be created

Co-authored-by: t-hamano <wildworks@git.wordpress.org>
Co-authored-by: ramonjd <ramonopoly@git.wordpress.org>
Co-authored-by: andrewserong <andrewserong@git.wordpress.org>
---
 .../components/use-block-drop-zone/index.js   | 80 +++++++++++++++----
 .../src/components/use-on-block-drop/index.js | 10 +--
 2 files changed, 67 insertions(+), 23 deletions(-)

diff --git a/packages/block-editor/src/components/use-block-drop-zone/index.js b/packages/block-editor/src/components/use-block-drop-zone/index.js
index 857a132f1f9fa4..415ed5070d28da 100644
--- a/packages/block-editor/src/components/use-block-drop-zone/index.js
+++ b/packages/block-editor/src/components/use-block-drop-zone/index.js
@@ -301,8 +301,10 @@ export default function useBlockDropZone( {
 		operation: 'insert',
 	} );
 
-	const { getBlockType } = useSelect( blocksStore );
+	const { getBlockType, getBlockVariations, getGroupingBlockName } =
+		useSelect( blocksStore );
 	const {
+		canInsertBlockType,
 		getBlockListSettings,
 		getBlocks,
 		getBlockIndex,
@@ -310,6 +312,7 @@ export default function useBlockDropZone( {
 		getBlockNamesByClientId,
 		getAllowedBlocks,
 		isDragging,
+		isGroupable,
 	} = unlock( useSelect( blockEditorStore ) );
 	const {
 		showInsertionPoint,
@@ -385,21 +388,66 @@ export default function useBlockDropZone( {
 					};
 				} );
 
+				const dropTargetPosition = getDropTargetPosition(
+					blocksData,
+					{ x: event.clientX, y: event.clientY },
+					getBlockListSettings( targetRootClientId )?.orientation,
+					{
+						dropZoneElement,
+						parentBlockClientId,
+						parentBlockOrientation: parentBlockClientId
+							? getBlockListSettings( parentBlockClientId )
+									?.orientation
+							: undefined,
+						rootBlockIndex: getBlockIndex( targetRootClientId ),
+					}
+				);
+
 				const [ targetIndex, operation, nearestSide ] =
-					getDropTargetPosition(
-						blocksData,
-						{ x: event.clientX, y: event.clientY },
-						getBlockListSettings( targetRootClientId )?.orientation,
-						{
-							dropZoneElement,
-							parentBlockClientId,
-							parentBlockOrientation: parentBlockClientId
-								? getBlockListSettings( parentBlockClientId )
-										?.orientation
-								: undefined,
-							rootBlockIndex: getBlockIndex( targetRootClientId ),
-						}
+					dropTargetPosition;
+
+				if ( operation === 'group' ) {
+					const targetBlock = blocks[ targetIndex ];
+					const areAllImages = [
+						targetBlock.name,
+						...draggedBlockNames,
+					].every( ( name ) => name === 'core/image' );
+					const canInsertGalleryBlock = canInsertBlockType(
+						'core/gallery',
+						targetRootClientId
 					);
+					const areGroupableBlocks = isGroupable( [
+						targetBlock.clientId,
+						getDraggedBlockClientIds(),
+					] );
+					const groupBlockVariations = getBlockVariations(
+						getGroupingBlockName(),
+						'block'
+					);
+					const canInsertRow =
+						groupBlockVariations &&
+						groupBlockVariations.find(
+							( { name } ) => name === 'group-row'
+						);
+
+					// If the dragged blocks and the target block are all images,
+					// check if it is creatable either a Row variation or a Gallery block.
+					if (
+						areAllImages &&
+						! canInsertGalleryBlock &&
+						( ! areGroupableBlocks || ! canInsertRow )
+					) {
+						return;
+					}
+					// If the dragged blocks and the target block are not all images,
+					// check if it is creatable a Row variation.
+					if (
+						! areAllImages &&
+						( ! areGroupableBlocks || ! canInsertRow )
+					) {
+						return;
+					}
+				}
 
 				registry.batch( () => {
 					setDropTarget( {
@@ -436,6 +484,10 @@ export default function useBlockDropZone( {
 				showInsertionPoint,
 				isDragging,
 				startDragging,
+				canInsertBlockType,
+				getBlockVariations,
+				getGroupingBlockName,
+				isGroupable,
 			]
 		),
 		200
diff --git a/packages/block-editor/src/components/use-on-block-drop/index.js b/packages/block-editor/src/components/use-on-block-drop/index.js
index 420cd398edfa39..75b9a44e166f5c 100644
--- a/packages/block-editor/src/components/use-on-block-drop/index.js
+++ b/packages/block-editor/src/components/use-on-block-drop/index.js
@@ -232,7 +232,6 @@ export default function useOnBlockDrop(
 		getBlocksByClientId,
 		getSettings,
 		getBlock,
-		isGroupable,
 	} = useSelect( blockEditorStore );
 	const { getGroupingBlockName } = useSelect( blocksStore );
 	const {
@@ -255,17 +254,11 @@ export default function useOnBlockDrop(
 			if ( ! Array.isArray( blocks ) ) {
 				blocks = [ blocks ];
 			}
-
 			const clientIds = getBlockOrder( targetRootClientId );
 			const clientId = clientIds[ targetBlockIndex ];
-			const blocksClientIds = blocks.map( ( block ) => block.clientId );
-			const areGroupableBlocks = isGroupable( [
-				...blocksClientIds,
-				clientId,
-			] );
 			if ( operation === 'replace' ) {
 				replaceBlocks( clientId, blocks, undefined, initialPosition );
-			} else if ( operation === 'group' && areGroupableBlocks ) {
+			} else if ( operation === 'group' ) {
 				const targetBlock = getBlock( clientId );
 				if ( nearestSide === 'left' ) {
 					blocks.push( targetBlock );
@@ -325,7 +318,6 @@ export default function useOnBlockDrop(
 			getBlockOrder,
 			targetRootClientId,
 			targetBlockIndex,
-			isGroupable,
 			operation,
 			replaceBlocks,
 			getBlock,