Try: Block API: Remove children source in favor of HTML string

blocks/api/factory.js

@@ -43,7 +43,7 @@ export function createBlock( name, blockAttributes = {}, innerBlocks = [] ) {
 
 	// Ensure attributes contains only values defined by block type, and merge
 	// default values for missing attributes.
-	const attributes = reduce( blockType.attributes, ( result, source, key ) => {
+	let attributes = reduce( blockType.attributes, ( result, source, key ) => {
 		const value = blockAttributes[ key ];
 		if ( undefined !== value ) {
 			result[ key ] = value;
@@ -54,6 +54,8 @@ export function createBlock( name, blockAttributes = {}, innerBlocks = [] ) {
 		return result;
 	}, {} );
 
+	attributes = applyFilters( 'blocks.createBlock.attributes', attributes, name, blockAttributes, innerBlocks );
+
 	// Blocks are stored with a unique ID, the assigned type name,
 	// and the block attributes.
 	return {
@@ -207,12 +209,14 @@ export function switchToBlockType( blocks, name ) {
 		return null;
 	}
 
-	let transformationResults;
-	if ( transformation.isMultiBlock ) {
-		transformationResults = transformation.transform( blocksArray.map( ( currentBlock ) => currentBlock.attributes ) );
-	} else {
-		transformationResults = transformation.transform( firstBlock.attributes );
+	const transformationArray = transformation.isMultiBlock ? blocksArray : [ firstBlock ];
+	let sourceBlocksAttributes = transformationArray.map( ( block ) => {
+		return applyFilters( 'blocks.switchToBlockType.sourceAttributes', block.attributes, sourceName );
+	} );
+	if ( ! transformation.isMultiBlock ) {
+		sourceBlocksAttributes = first( sourceBlocksAttributes );
 	}
+	let transformationResults = transformation.transform( sourceBlocksAttributes );
 
 	// Ensure that the transformation function returned an object or an array
 	// of objects.

blocks/api/parser.js

@@ -1,13 +1,14 @@
 /**
  * External dependencies
  */
-import { parse as hpqParse } from 'hpq';
+import { parse as hpqParse, attr, prop, html, text, query } from 'hpq';
 import { mapValues, omit } from 'lodash';
 
 /**
  * WordPress dependencies
  */
 import { autop } from '@wordpress/autop';
+import { applyFilters } from '@wordpress/hooks';
 
 /**
  * Internal dependencies
@@ -17,7 +18,6 @@ import { getBlockType, getUnknownTypeHandlerName } from './registration';
 import { createBlock } from './factory';
 import { isValidBlock } from './validation';
 import { getCommentDelimitedContent } from './serializer';
-import { attr, prop, html, text, query, node, children } from './matchers';
 
 /**
  * Returns value coerced to the specified JSON schema type string.
@@ -75,10 +75,6 @@ export function matcherFromSource( sourceConfig ) {
 			return html( sourceConfig.selector );
 		case 'text':
 			return text( sourceConfig.selector );
-		case 'children':
-			return children( sourceConfig.selector );
-		case 'node':
-			return node( sourceConfig.selector );
 		case 'query':
 			const subMatchers = mapValues( sourceConfig.query, matcherFromSource );
 			return query( sourceConfig.selector, subMatchers );
@@ -118,7 +114,15 @@ export function getBlockAttribute( attributeKey, attributeSchema, innerHTML, com
 			break;
 	}
 
-	return value === undefined ? attributeSchema.default : asType( value, attributeSchema.type );
+	value = applyFilters( 'blocks.getBlockAttribute.source', value, attributeSchema, innerHTML, commentAttributes );
+
+	if ( value === undefined ) {
+		value = attributeSchema.default;
+	} else {
+		value = asType( value, attributeSchema.type );
+	}
+
+	return applyFilters( 'blocks.getBlockAttribute', value, attributeSchema, innerHTML, commentAttributes );
 }
 
 /**
@@ -142,14 +146,15 @@ export function getBlockAttributes( blockType, innerHTML, attributes ) {
  * Attempt to parse the innerHTML using using a supplied `deprecated`
  * definition.
  *
- * @param {?Object} blockType  Block type.
- * @param {string}  innerHTML  Raw block content.
- * @param {?Object} attributes Known block attributes (from delimiters).
+ * @param {string} name       Block name.
+ * @param {Object} attributes Known block attributes (from delimiters).
+ * @param {string} innerHTML  Raw block content.
  *
- * @return {Object} Block attributes.
+ * @return {?Object} Migrated block attributes, if possible.
  */
-export function getAttributesFromDeprecatedVersion( blockType, innerHTML, attributes ) {
-	if ( ! blockType.deprecated ) {
+export function getAttributesFromDeprecatedVersion( name, attributes, innerHTML ) {
+	const blockType = getBlockType( name );
+	if ( ! blockType || ! blockType.deprecated ) {
 		return;
 	}
 
@@ -164,11 +169,25 @@ export function getAttributesFromDeprecatedVersion( blockType, innerHTML, attrib
 			// Try to validate the parsed block using this same deprecated version.
 			// Ignore this version if the the validation fails.
 			const deprecatedBlockAttributes = getBlockAttributes( deprecatedBlockType, innerHTML, attributes );
-			const migratedBlockAttributes = deprecatedBlockType.migrate ? deprecatedBlockType.migrate( deprecatedBlockAttributes ) : deprecatedBlockAttributes;
 			const isValid = isValidBlock( innerHTML, deprecatedBlockType, deprecatedBlockAttributes );
-			if ( isValid ) {
-				return migratedBlockAttributes;
+			if ( ! isValid ) {
+				continue;
+			}
+
+			let migratedBlockAttributes = deprecatedBlockAttributes;
+			if ( deprecatedBlockType.migrate ) {
+				migratedBlockAttributes = deprecatedBlockType.migrate( deprecatedBlockAttributes );
 			}
+
+			migratedBlockAttributes = applyFilters(
+				'blocks.getAttributesFromDeprecatedVersion.migratedBlockAttributes',
+				migratedBlockAttributes,
+				name,
+				attributes,
+				innerHTML
+			);
+
+			return migratedBlockAttributes;
 		} catch ( error ) {
 			// ignore error, it means this deprecated version is invalid
 		}
@@ -257,7 +276,7 @@ export function createBlockWithFallback( blockNode ) {
 	// invalidating content written in previous formats.
 	if ( ! block.isValid ) {
 		const attributesParsedWithDeprecatedVersion = getAttributesFromDeprecatedVersion(
-			blockType, innerHTML, attributes
+			name, attributes, innerHTML
 		);
 
 		if ( attributesParsedWithDeprecatedVersion ) {

blocks/api/raw-handling/test/integration/evernote-out.html

@@ -1,7 +1,7 @@
 <!-- wp:paragraph -->
 <p>This is a <em>paragraph</em>.
-    <br/>This is a <a href="https://w.org">link</a>.
-    <br/></p>
+    <br>This is a <a href="https://w.org">link</a>.
+    <br></p>
 <!-- /wp:paragraph -->
 
 <!-- wp:list -->

blocks/api/raw-handling/test/integration/google-docs-out.html

@@ -1,13 +1,13 @@
 <!-- wp:paragraph -->
-<p>This is a <strong>title</strong><br/></p>
+<p>This is a <strong>title</strong><br></p>
 <!-- /wp:paragraph -->
 
 <!-- wp:heading -->
 <h2>This is a <em>heading</em></h2>
 <!-- /wp:heading -->
 
 <!-- wp:paragraph -->
-<p>This is a <strong>paragraph</strong> with a <a href="https://w.org">link</a>.<br/></p>
+<p>This is a <strong>paragraph</strong> with a <a href="https://w.org">link</a>.<br></p>
 <!-- /wp:paragraph -->
 
 <!-- wp:list -->
@@ -56,7 +56,7 @@ <h2>This is a <em>heading</em></h2>
 <!-- /wp:separator -->
 
 <!-- wp:paragraph -->
-<p>An image:<br/></p>
+<p>An image:<br></p>
 <!-- /wp:paragraph -->
 
 <!-- wp:image -->

blocks/api/raw-handling/test/integration/ms-word-online-out.html

@@ -1,52 +1,52 @@
 <!-- wp:paragraph -->
-<p>This is a <em>heading</em> </p>
+<p>This is a <em>heading</em>&nbsp;</p>
 <!-- /wp:paragraph -->
 
 <!-- wp:paragraph -->
-<p>This is a <strong>paragraph </strong>with a <a href="https://w.org/">link</a>. </p>
+<p>This is a <strong>paragraph </strong>with a <a href="https://w.org/">link</a>.&nbsp;</p>
 <!-- /wp:paragraph -->
 
 <!-- wp:list -->
 <ul>
-    <li>A </li>
-    <li>Bulleted </li>
-    <li>Indented </li>
-    <li>List </li>
+    <li>A&nbsp;</li>
+    <li>Bulleted&nbsp;</li>
+    <li>Indented&nbsp;</li>
+    <li>List&nbsp;</li>
 </ul>
 <!-- /wp:list -->
 
 <!-- wp:list -->
 <ol>
-    <li>One </li>
-    <li>Two </li>
-    <li>Three </li>
+    <li>One&nbsp;</li>
+    <li>Two&nbsp;</li>
+    <li>Three&nbsp;</li>
 </ol>
 <!-- /wp:list -->
 
 <!-- wp:table -->
 <table class="wp-block-table">
     <tbody>
         <tr>
-            <td>One </td>
-            <td>Two </td>
-            <td>Three </td>
+            <td>One&nbsp;</td>
+            <td>Two&nbsp;</td>
+            <td>Three&nbsp;</td>
         </tr>
         <tr>
-            <td>1 </td>
-            <td>2 </td>
-            <td>3 </td>
+            <td>1&nbsp;</td>
+            <td>2&nbsp;</td>
+            <td>3&nbsp;</td>
         </tr>
         <tr>
-            <td>I </td>
-            <td>II </td>
-            <td>III </td>
+            <td>I&nbsp;</td>
+            <td>II&nbsp;</td>
+            <td>III&nbsp;</td>
         </tr>
     </tbody>
 </table>
 <!-- /wp:table -->
 
 <!-- wp:paragraph -->
-<p>An image: </p>
+<p>An image:&nbsp;</p>
 <!-- /wp:paragraph -->
 
 <!-- wp:image -->

blocks/api/raw-handling/test/integration/plain-out.html

@@ -1,7 +1,7 @@
 <!-- wp:paragraph -->
-<p>test<br/>test</p>
+<p>test<br>test</p>
 <!-- /wp:paragraph -->
 
 <!-- wp:paragraph -->
-<p>test<br/></p>
+<p>test<br></p>
 <!-- /wp:paragraph -->

blocks/api/serializer.js

@@ -1,7 +1,7 @@
 /**
  * External dependencies
  */
-import { isEmpty, reduce, isObject, castArray, startsWith } from 'lodash';
+import { isEmpty, reduce, isPlainObject, castArray, startsWith } from 'lodash';
 import { html as beautifyHtml } from 'js-beautify';
 import isEqualShallow from 'is-equal-shallow';
 
@@ -50,9 +50,19 @@ export function getSaveElement( blockType, attributes, innerBlocks = [] ) {
 		save = instance.render.bind( instance );
 	}
 
+	/**
+	 * Filters the attributes of a block before generating serialized result.
+	 * Avoid mutating the attribute value, as it should only be effective for
+	 * the duration of the serialization.
+	 *
+	 * @param {Object}      attributes Block attributes.
+	 * @param {WPBlockType} blockType  Block type definition.
+	 */
+	attributes = applyFilters( 'blocks.getSaveElement.attributes', attributes, blockType.name, innerBlocks );
+
 	let element = save( { attributes, innerBlocks } );
 
-	if ( isObject( element ) && hasFilter( 'blocks.getSaveContent.extraProps' ) ) {
+	if ( isPlainObject( element ) && hasFilter( 'blocks.getSaveContent.extraProps' ) ) {
 		/**
 		 * Filters the props applied to the block save result element.
 		 *