From bf163d426b8b1424cc7ddcda0f5e51da86c809c9 Mon Sep 17 00:00:00 2001
From: Robert Anderson <robert@noisysocks.com>
Date: Mon, 19 Jun 2023 14:43:08 +1000
Subject: [PATCH] Prevent BlockBreadcrumb from re-rendering unnecessarily when
 typing

---
 .../src/components/block-breadcrumb/index.js  |  8 +-
 .../src/store/private-selectors.js            | 26 +++++
 .../src/store/test/private-selectors.js       | 96 +++++++++++++++++++
 3 files changed, 124 insertions(+), 6 deletions(-)

diff --git a/packages/block-editor/src/components/block-breadcrumb/index.js b/packages/block-editor/src/components/block-breadcrumb/index.js
index 9e4ab5391d8c4..13cc93d41a981 100644
--- a/packages/block-editor/src/components/block-breadcrumb/index.js
+++ b/packages/block-editor/src/components/block-breadcrumb/index.js
@@ -26,15 +26,11 @@ function BlockBreadcrumb( { rootLabelText } ) {
 		const {
 			getSelectionStart,
 			getSelectedBlockClientId,
-			getBlockParents,
-			getBlockEditingMode,
+			getEnabledBlockParents,
 		} = unlock( select( blockEditorStore ) );
 		const selectedBlockClientId = getSelectedBlockClientId();
 		return {
-			parents: getBlockParents( selectedBlockClientId ).filter(
-				( parentClientId ) =>
-					getBlockEditingMode( parentClientId ) !== 'disabled'
-			),
+			parents: getEnabledBlockParents( selectedBlockClientId ),
 			clientId: selectedBlockClientId,
 			hasSelection: !! getSelectionStart().clientId,
 		};
diff --git a/packages/block-editor/src/store/private-selectors.js b/packages/block-editor/src/store/private-selectors.js
index c250b649569f0..1eff2e8510dcc 100644
--- a/packages/block-editor/src/store/private-selectors.js
+++ b/packages/block-editor/src/store/private-selectors.js
@@ -17,6 +17,7 @@ import {
 	getTemplateLock,
 	getBlockName,
 	getBlockOrder,
+	getBlockParents,
 } from './selectors';
 
 /**
@@ -169,3 +170,28 @@ export const getListViewClientIdsTree = createSelector(
 		state.blockListSettings,
 	]
 );
+
+/**
+ * Returns a list of a given block's ancestors, from top to bottom. Blocks with
+ * a 'disabled' editing mode are excluded.
+ *
+ * @see getBlockParents
+ *
+ * @param {Object}  state     Global application state.
+ * @param {string}  clientId  The block client ID.
+ * @param {boolean} ascending Order results from bottom to top (true) or top
+ *                            to bottom (false).
+ */
+export const getEnabledBlockParents = createSelector(
+	( state, clientId, ascending = false ) => {
+		return getBlockParents( state, clientId, ascending ).filter(
+			( parent ) => getBlockEditingMode( state, parent ) !== 'disabled'
+		);
+	},
+	( state ) => [
+		state.blocks.parents,
+		state.blockEditingModes,
+		state.settings.templateLock,
+		state.blockListSettings,
+	]
+);
diff --git a/packages/block-editor/src/store/test/private-selectors.js b/packages/block-editor/src/store/test/private-selectors.js
index ab0d4b11c5bf4..30cf702c60526 100644
--- a/packages/block-editor/src/store/test/private-selectors.js
+++ b/packages/block-editor/src/store/test/private-selectors.js
@@ -12,6 +12,7 @@ import {
 	getBlockEditingMode,
 	isBlockSubtreeDisabled,
 	getListViewClientIdsTree,
+	getEnabledBlockParents,
 } from '../private-selectors';
 
 jest.mock( '@wordpress/data/src/select', () => ( {
@@ -554,4 +555,99 @@ describe( 'private selectors', () => {
 			] );
 		} );
 	} );
+
+	describe( 'getEnabledBlockParents', () => {
+		it( 'should return an empty array if block is at the root', () => {
+			const state = {
+				settings: {},
+				blocks: {
+					parents: new Map( [
+						[ '6cf70164-9097-4460-bcbf-200560546988', '' ],
+					] ),
+				},
+				blockEditingModes: new Map(),
+			};
+			expect(
+				getEnabledBlockParents(
+					state,
+					'6cf70164-9097-4460-bcbf-200560546988'
+				)
+			).toEqual( [] );
+		} );
+
+		it( 'should return non-disabled parents', () => {
+			const state = {
+				settings: {},
+				blocks: {
+					parents: new Map( [
+						[ 'ef45d5fd-5234-4fd5-ac4f-c3736c7f9337', '' ],
+						[
+							'9b9c5c3f-2e46-4f02-9e14-9fe9515b958f',
+							'ef45d5fd-5234-4fd5-ac4f-c3736c7f9337',
+						],
+						[
+							'e178812d-ce5e-48c7-a945-8ae4ffcbbb7c',
+							'9b9c5c3f-2e46-4f02-9e14-9fe9515b958f',
+						],
+						[
+							'4c2b7140-fffd-44b4-b2a7-820c670a6514',
+							'e178812d-ce5e-48c7-a945-8ae4ffcbbb7c',
+						],
+					] ),
+				},
+				blockEditingModes: new Map( [
+					[ '', 'disabled' ],
+					[ '9b9c5c3f-2e46-4f02-9e14-9fe9515b958f', 'default' ],
+				] ),
+				blockListSettings: {},
+			};
+			expect(
+				getEnabledBlockParents(
+					state,
+					'4c2b7140-fffd-44b4-b2a7-820c670a6514'
+				)
+			).toEqual( [
+				'9b9c5c3f-2e46-4f02-9e14-9fe9515b958f',
+				'e178812d-ce5e-48c7-a945-8ae4ffcbbb7c',
+			] );
+		} );
+
+		it( 'should order from bottom to top if ascending is true', () => {
+			const state = {
+				settings: {},
+				blocks: {
+					parents: new Map( [
+						[ 'ef45d5fd-5234-4fd5-ac4f-c3736c7f9337', '' ],
+						[
+							'9b9c5c3f-2e46-4f02-9e14-9fe9515b958f',
+							'ef45d5fd-5234-4fd5-ac4f-c3736c7f9337',
+						],
+						[
+							'e178812d-ce5e-48c7-a945-8ae4ffcbbb7c',
+							'9b9c5c3f-2e46-4f02-9e14-9fe9515b958f',
+						],
+						[
+							'4c2b7140-fffd-44b4-b2a7-820c670a6514',
+							'e178812d-ce5e-48c7-a945-8ae4ffcbbb7c',
+						],
+					] ),
+				},
+				blockEditingModes: new Map( [
+					[ '', 'disabled' ],
+					[ '9b9c5c3f-2e46-4f02-9e14-9fe9515b958f', 'default' ],
+				] ),
+				blockListSettings: {},
+			};
+			expect(
+				getEnabledBlockParents(
+					state,
+					'4c2b7140-fffd-44b4-b2a7-820c670a6514',
+					true
+				)
+			).toEqual( [
+				'e178812d-ce5e-48c7-a945-8ae4ffcbbb7c',
+				'9b9c5c3f-2e46-4f02-9e14-9fe9515b958f',
+			] );
+		} );
+	} );
 } );