Send all fields when transmitting an autosave.

editor/store/effects.js

@@ -2,7 +2,7 @@
  * External dependencies
  */
 import { BEGIN, COMMIT, REVERT } from 'redux-optimist';
-import { get, includes, last, map, castArray, uniqueId } from 'lodash';
+import { get, includes, last, map, castArray, uniqueId, pick } from 'lodash';
 
 /**
  * WordPress dependencies
@@ -62,6 +62,7 @@ import {
 	isBlockSelected,
 	getTemplate,
 	getTemplateLock,
+	getAutosave,
 	POST_UPDATE_TRANSACTION_ID,
 } from './selectors';
 
@@ -103,7 +104,7 @@ export default {
 
 		const post = getCurrentPost( state );
 		const edits = getPostEdits( state );
-		const toSend = {
+		let toSend = {
 			...edits,
 			content: getEditedPostContent( state ),
 			id: post.id,
@@ -118,7 +119,14 @@ export default {
 
 		let request;
 		if ( isAutosave ) {
-			toSend.parent = post.id;
+			// Ensure autosaves contain all expected fields, using autosave or
+			// post values as fallback if not otherwise included in edits.
+			toSend = {
+				...pick( post, [ 'title', 'content', 'excerpt' ] ),
+				...getAutosave( state ),
+				...toSend,
+				parent: post.id,
+			};
 
 			request = wp.apiRequest( {
 				path: `/wp/v2/${ basePath }/${ post.id }/autosaves`,

editor/store/selectors.js

@@ -345,11 +345,25 @@ export function isEditedPostAutosaveable( state ) {
 	}
 
 	// If the title, excerpt or content has changed, the post is autosaveable.
+	const autosave = getAutosave( state );
 	return [ 'title', 'excerpt', 'content' ].some( ( field ) => (
-		state.autosave[ field ] !== getEditedPostAttribute( state, field )
+		autosave[ field ] !== getEditedPostAttribute( state, field )
 	) );
 }
 
+/**
+ * Returns the current autosave, or null if one is not set (i.e. if the post
+ * has yet to be autosaved, or has been saved or published since the last
+ * autosave).
+ *
+ * @param {Object} state Editor state.
+ *
+ * @return {?Object} Current autosave, if exists.
+ */
+export function getAutosave( state ) {
+	return state.autosave;
+}
+
 /**
  * Returns the true if there is an existing autosave, otherwise false.
  *
@@ -358,7 +372,7 @@ export function isEditedPostAutosaveable( state ) {
  * @return {boolean} Whether there is an existing autosave.
  */
 export function hasAutosave( state ) {
-	return !! state.autosave;
+	return !! getAutosave( state );
 }
 
 /**

editor/store/test/selectors.js

@@ -36,6 +36,8 @@ const {
 	isEditedPostPublishable,
 	isEditedPostSaveable,
 	isEditedPostAutosaveable,
+	getAutosave,
+	hasAutosave,
 	isEditedPostEmpty,
 	isEditedPostBeingScheduled,
 	getEditedPostPreviewLink,
@@ -1108,6 +1110,49 @@ describe( 'selectors', () => {
 		} );
 	} );
 
+	describe( 'getAutosave', () => {
+		it( 'returns null if there is no autosave', () => {
+			const state = {
+				autosave: null,
+			};
+
+			const result = getAutosave( state );
+
+			expect( result ).toBe( null );
+		} );
+
+		it( 'returns the autosave', () => {
+			const autosave = { title: '', excerpt: '', content: '' };
+			const state = { autosave };
+
+			const result = getAutosave( state );
+
+			expect( result ).toEqual( autosave );
+		} );
+	} );
+
+	describe( 'hasAutosave', () => {
+		it( 'returns false if there is no autosave', () => {
+			const state = {
+				autosave: null,
+			};
+
+			const result = hasAutosave( state );
+
+			expect( result ).toBe( false );
+		} );
+
+		it( 'returns true if there is a autosave', () => {
+			const state = {
+				autosave: { title: '', excerpt: '', content: '' },
+			};
+
+			const result = hasAutosave( state );
+
+			expect( result ).toBe( true );
+		} );
+	} );
+
 	describe( 'isEditedPostEmpty', () => {
 		it( 'should return true if no blocks and no content', () => {
 			const state = {