From 7e223fcd8c72411921bf6b25ef07663057ea8d2f Mon Sep 17 00:00:00 2001
From: Gary Pendergast <gary@pento.net>
Date: Wed, 25 Jul 2018 14:53:20 +1000
Subject: [PATCH] Allow ID attributes on elements that belong to an anchor
 block (#8124)

Fixes #7335.
---
 packages/blocks/src/api/raw-handling/test/utils.js |  6 ++++++
 packages/blocks/src/api/raw-handling/utils.js      | 14 +++++++++++++-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/packages/blocks/src/api/raw-handling/test/utils.js b/packages/blocks/src/api/raw-handling/test/utils.js
index b8c2d2f46e673..3cbdc68a5e268 100644
--- a/packages/blocks/src/api/raw-handling/test/utils.js
+++ b/packages/blocks/src/api/raw-handling/test/utils.js
@@ -109,6 +109,12 @@ describe( 'removeInvalidHTML', () => {
 		expect( removeInvalidHTML( input, schema ) ).toBe( output );
 	} );
 
+	it( 'should remove id attributes', () => {
+		const input = '<p id="foo">test</p>';
+		const output = '<p>test</p>';
+		expect( removeInvalidHTML( input, schema ) ).toBe( output );
+	} );
+
 	it( 'should remove multiple attributes', () => {
 		const input = '<p class="test" id="test">test</p>';
 		const output = '<p>test</p>';
diff --git a/packages/blocks/src/api/raw-handling/utils.js b/packages/blocks/src/api/raw-handling/utils.js
index 5b233201eb98e..3aa3e438c2e51 100644
--- a/packages/blocks/src/api/raw-handling/utils.js
+++ b/packages/blocks/src/api/raw-handling/utils.js
@@ -7,6 +7,7 @@ import { omit, mergeWith, includes, noop } from 'lodash';
  * WordPress dependencies
  */
 import { unwrap, insertAfter, remove } from '@wordpress/dom';
+import { hasBlockSupport } from '..';
 
 /**
  * Browser dependencies
@@ -67,7 +68,18 @@ export function isPhrasingContent( node ) {
  * @return {Object} A complete block content schema.
  */
 export function getBlockContentSchema( transforms ) {
-	const schemas = transforms.map( ( { schema } ) => schema );
+	const schemas = transforms.map( ( { blockName, schema } ) => {
+		// If the block supports the "anchor" functionality, it needs to keep its ID attribute.
+		if ( hasBlockSupport( blockName, 'anchor' ) ) {
+			for ( const tag in schema ) {
+				if ( ! schema[ tag ].attributes ) {
+					schema[ tag ].attributes = [];
+				}
+				schema[ tag ].attributes.push( 'id' );
+			}
+		}
+		return schema;
+	} );
 
 	return mergeWith( {}, ...schemas, ( objValue, srcValue, key ) => {
 		if ( key === 'children' ) {