From 02b19f337f0a045fe3ba1c8b21e8ca016763c8b8 Mon Sep 17 00:00:00 2001
From: Catrope <roan.kattouw@gmail.com>
Date: Wed, 6 Jun 2012 15:33:42 -0700
Subject: [PATCH] Add zero-length text nodes to empty content nodes

This is needed to make the results of certain transactions' tree sync
round-trip cleanly through the ve.dm.Document constructor

Change-Id: I2ab0758ec6bd7afba5b6645c7330f9fa2d45205d
---
 modules/ve2/dm/ve.dm.Document.js    | 9 +++++++++
 tests/ve2/dm/ve.dm.Document.test.js | 9 ++++++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/modules/ve2/dm/ve.dm.Document.js b/modules/ve2/dm/ve.dm.Document.js
index f66d19d254..6e2553ecf2 100644
--- a/modules/ve2/dm/ve.dm.Document.js
+++ b/modules/ve2/dm/ve.dm.Document.js
@@ -119,6 +119,15 @@ ve.dm.Document = function( data, parentDocument ) {
 						// This can only happen if we got unbalanced data
 						throw 'Unbalanced input passed to document';
 					}
+
+					if ( children.length === 0 &&
+						ve.dm.nodeFactory.canNodeContainContent(
+							currentNode.getType()
+						)
+					) {
+						// Content nodes cannot be childless, add a zero-length text node
+						children.push( new ve.dm.TextNode( 0 ) );
+					}
 					// Attach the children to the node
 					ve.batchSplice( currentNode, 0, 0, children );
 				}
diff --git a/tests/ve2/dm/ve.dm.Document.test.js b/tests/ve2/dm/ve.dm.Document.test.js
index 611b362836..c0b3469346 100644
--- a/tests/ve2/dm/ve.dm.Document.test.js
+++ b/tests/ve2/dm/ve.dm.Document.test.js
@@ -2,7 +2,7 @@ module( 've.dm.Document' );
 
 /* Tests */
 
-test( 'constructor', 3, function() {
+test( 'constructor', 4, function() {
 	var doc = new ve.dm.Document( ve.dm.example.data );
 	deepEqual(
 		ve.example.getNodeTreeSummary( doc.getDocumentNode() ),
@@ -27,6 +27,13 @@ test( 'constructor', 3, function() {
 		ve.example.getNodeTreeSummary( new ve.dm.DocumentNode( [ new ve.dm.TextNode( 4 ) ] ) ),
 		'plain text input is handled correctly'
 	);
+
+	doc = new ve.dm.Document( [ { 'type': 'paragraph' }, { 'type': '/paragraph' } ] );
+	deepEqual(
+		ve.example.getNodeTreeSummary( doc.getDocumentNode() ),
+		ve.example.getNodeTreeSummary( new ve.dm.DocumentNode( [ new ve.dm.ParagraphNode( [ new ve.dm.TextNode( 0 ) ] ) ] ) ),
+		'empty paragraph gets a zero-length text node'
+	);
 } );
 
 test( 'getData', 1, function() {