From 388ec6e4362ac423e2653228d905564117c6cc53 Mon Sep 17 00:00:00 2001
From: Riad Benguella <benguella@gmail.com>
Date: Tue, 18 Sep 2018 10:44:33 +0100
Subject: [PATCH] Fix custom classNames for dynamic blocks

---
 packages/editor/src/hooks/custom-class-name.js   |  3 +--
 .../editor/src/hooks/test/custom-class-name.js   | 16 ++++++++++++++++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/packages/editor/src/hooks/custom-class-name.js b/packages/editor/src/hooks/custom-class-name.js
index 093863fbb7bd0..9779dfd1a2bb5 100644
--- a/packages/editor/src/hooks/custom-class-name.js
+++ b/packages/editor/src/hooks/custom-class-name.js
@@ -55,7 +55,6 @@ export function addAttribute( settings ) {
 export const withInspectorControl = createHigherOrderComponent( ( BlockEdit ) => {
 	return ( props ) => {
 		const hasCustomClassName = hasBlockSupport( props.name, 'customClassName', true );
-
 		if ( hasCustomClassName && props.isSelected ) {
 			return (
 				<Fragment>
@@ -145,7 +144,7 @@ export function addParsedDifference( blockAttributes, blockType, innerHTML ) {
 
 		if ( customClasses.length ) {
 			blockAttributes.className = customClasses.join( ' ' );
-		} else {
+		} else if ( serialized ) {
 			delete blockAttributes.className;
 		}
 	}
diff --git a/packages/editor/src/hooks/test/custom-class-name.js b/packages/editor/src/hooks/test/custom-class-name.js
index ea7b441de8459..6b2c84b886139 100644
--- a/packages/editor/src/hooks/test/custom-class-name.js
+++ b/packages/editor/src/hooks/test/custom-class-name.js
@@ -15,6 +15,12 @@ describe( 'custom className', () => {
 		title: 'block title',
 	};
 
+	const dynamicBlockSettings = {
+		save: () => null,
+		category: 'common',
+		title: 'block title',
+	};
+
 	describe( 'addAttribute()', () => {
 		const addAttribute = applyFilters.bind( null, 'blocks.registerBlockType' );
 
@@ -150,5 +156,15 @@ describe( 'custom className', () => {
 
 			expect( attributes.className ).toBe( 'custom1 custom3' );
 		} );
+
+		it( 'should not remove the custom classes for dynamic blocks', () => {
+			const attributes = addParsedDifference(
+				{ className: 'custom1' },
+				dynamicBlockSettings,
+				null,
+			);
+
+			expect( attributes.className ).toBe( 'custom1' );
+		} );
 	} );
 } );