Check if aspect ratio class exists before regenerating. Resets if the…

… URL has changed.

packages/block-library/src/embed/edit.js

@@ -4,6 +4,7 @@
 import {
 	createUpgradedEmbedBlock,
 	getClassNames,
+	removeAspectRatioClasses,
 	fallback,
 	getEmbedInfoByProvider,
 	getMergedAttributesWithPreview,
@@ -188,8 +189,14 @@ const EmbedEdit = ( props ) => {
 							event.preventDefault();
 						}
 
+						// If the embed URL was changed, we need to reset the aspect ratio class.
+						// To do this we have to remove the existing ratio class so it can be recalculated.
+						const blockClass = removeAspectRatioClasses(
+							attributes.className
+						);
+
 						setIsEditingURL( false );
-						setAttributes( { url } );
+						setAttributes( { url, className: blockClass } );
 					} }
 					value={ url }
 					cannotEmbed={ cannotEmbed }

packages/block-library/src/embed/util.js

@@ -152,6 +152,21 @@ export const createUpgradedEmbedBlock = (
 	} );
 };
 
+/**
+ * Determine if the block already has an aspect ratio class applied.
+ *
+ * @param {string} existingClassNames Existing block classes.
+ * @return {boolean} True or false if the classnames contain an aspect ratio class.
+ */
+export const hasAspectRatioClass = ( existingClassNames ) => {
+	if ( ! existingClassNames ) {
+		return false;
+	}
+	return ASPECT_RATIOS.some( ( { className } ) =>
+		existingClassNames.includes( className )
+	);
+};
+
 /**
  * Removes all previously set aspect ratio related classes and return the rest
  * existing class names.
@@ -311,6 +326,14 @@ export const getMergedAttributesWithPreview = (
 	ignorePreviousClassName = false
 ) => {
 	const { allowResponsive, className } = currentAttributes;
+
+	// Aspect ratio classes are removed when the embed URL is updated.
+	// If the embed already has an aspect ratio class, that means the URL has not changed.
+	// Which also means no need to regenerate it.
+	if ( hasAspectRatioClass( className ) ) {
+		return currentAttributes;
+	}
+
 	return {
 		...currentAttributes,
 		...getAttributesFromPreview(