From a882a3f0bc2831c832dfc06a6d98011ef2cab5ca Mon Sep 17 00:00:00 2001
From: Andrew Duthie <andrew@andrewduthie.com>
Date: Wed, 22 May 2019 11:29:23 -0400
Subject: [PATCH] Block Editor: Partition attributes updates to avoid
 conflating meta and blocks attributes

---
 .../src/components/block-list/block.js        | 40 +++++++++++++------
 .../plugins/meta-attribute-block.test.js      | 12 +++++-
 2 files changed, 39 insertions(+), 13 deletions(-)

diff --git a/packages/block-editor/src/components/block-list/block.js b/packages/block-editor/src/components/block-list/block.js
index cccebd02de640f..a9b28f618daf5f 100644
--- a/packages/block-editor/src/components/block-list/block.js
+++ b/packages/block-editor/src/components/block-list/block.js
@@ -644,18 +644,34 @@ const applyWithDispatch = withDispatch( ( dispatch, ownProps, { select } ) => {
 		setAttributes( newAttributes ) {
 			const { name, clientId } = ownProps;
 			const type = getBlockType( name );
-			updateBlockAttributes( clientId, newAttributes );
-			const metaAttributes = reduce(
-				newAttributes,
-				( result, value, key ) => {
-					if ( get( type, [ 'attributes', key, 'source' ] ) === 'meta' ) {
-						result[ type.attributes[ key ].meta ] = value;
-					}
-
-					return result;
-				},
-				{}
-			);
+
+			function isMetaAttribute( key ) {
+				return get( type, [ 'attributes', key, 'source' ] ) === 'meta';
+			}
+
+			// Partition new attributes to delegate update behavior by source.
+			//
+			// TODO: A consolidated approach to external attributes sourcing
+			// should be devised to avoid specific handling for meta, enable
+			// additional attributes sources.
+			//
+			// See: https://github.com/WordPress/gutenberg/issues/2759
+			const {
+				blockAttributes,
+				metaAttributes,
+			} = reduce( newAttributes, ( result, value, key ) => {
+				if ( isMetaAttribute( key ) ) {
+					result.metaAttributes[ type.attributes[ key ].meta ] = value;
+				} else {
+					result.blockAttributes[ key ] = value;
+				}
+
+				return result;
+			}, { blockAttributes: {}, metaAttributes: {} } );
+
+			if ( size( blockAttributes ) ) {
+				updateBlockAttributes( clientId, blockAttributes );
+			}
 
 			if ( size( metaAttributes ) ) {
 				const { getSettings } = select( 'core/block-editor' );
diff --git a/packages/e2e-tests/specs/plugins/meta-attribute-block.test.js b/packages/e2e-tests/specs/plugins/meta-attribute-block.test.js
index 5de9ea1f6c619b..0e87fdeefea616 100644
--- a/packages/e2e-tests/specs/plugins/meta-attribute-block.test.js
+++ b/packages/e2e-tests/specs/plugins/meta-attribute-block.test.js
@@ -8,6 +8,7 @@ import {
 	getEditedPostContent,
 	insertBlock,
 	saveDraft,
+	pressKeyTimes,
 } from '@wordpress/e2e-test-utils';
 
 describe( 'Block with a meta attribute', () => {
@@ -25,7 +26,16 @@ describe( 'Block with a meta attribute', () => {
 
 	it( 'Should persist the meta attribute properly', async () => {
 		await insertBlock( 'Test Meta Attribute Block' );
-		await page.keyboard.type( 'Meta Value' );
+		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 ' );
+
 		await saveDraft();
 		await page.reload();