From ddc056a40a305c6be31bd7e296598dfbd1f8e46c Mon Sep 17 00:00:00 2001
From: Ed Sanders <esanders@wikimedia.org>
Date: Mon, 2 Oct 2017 16:26:16 +0100
Subject: [PATCH] MWExtensionWindow: Always send a string to
 setValueAndWhitespace

Bug: T177180
Change-Id: I3a32e1b22e82bc0c182d26a952e7592aafd4b5e4
---
 modules/ve-mw/ui/ve.ui.MWExtensionWindow.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/modules/ve-mw/ui/ve.ui.MWExtensionWindow.js b/modules/ve-mw/ui/ve.ui.MWExtensionWindow.js
index 748b3338ea..0529b2cd40 100644
--- a/modules/ve-mw/ui/ve.ui.MWExtensionWindow.js
+++ b/modules/ve-mw/ui/ve.ui.MWExtensionWindow.js
@@ -83,7 +83,7 @@ ve.ui.MWExtensionWindow.prototype.getSetupProcess = function ( data, process ) {
 		if ( this.selectedNode ) {
 			mwData = this.selectedNode.getAttribute( 'mw' );
 			// mwData.body can be null in <selfclosing/> extensions
-			this.input.setValueAndWhitespace( mwData.body && mwData.body.extsrc );
+			this.input.setValueAndWhitespace( ( mwData.body && mwData.body.extsrc ) || '' );
 			this.originalMwData = mwData;
 		} else {
 			if ( !this.constructor.static.modelClasses[ 0 ].static.isContent ) {