fix null ref when updating component root from null to something

render/render.js

@@ -243,7 +243,8 @@ module.exports = function($window) {
 		vnode.instance = Node.normalize(vnode.tag.view.call(vnode.state, vnode))
 		updateLifecycle(vnode.tag, vnode, hooks, recycling)
 		if (vnode.instance != null) {
-			updateNode(parent, old.instance, vnode.instance, hooks, nextSibling, recycling, ns)
+			if (old.instance == null) insertNode(parent, createNode(vnode.instance, hooks, ns), nextSibling)
+			else updateNode(parent, old.instance, vnode.instance, hooks, nextSibling, recycling, ns)
 			vnode.dom = vnode.instance.dom
 			vnode.domSize = vnode.instance.domSize
 		}

render/tests/test-component.js

@@ -54,6 +54,32 @@ o.spec("component", function() {
 			o(root.firstChild.attributes["id"].nodeValue).equals("c")
 			o(root.firstChild.firstChild.nodeValue).equals("d")
 		})
+		o("updates from null", function() {
+			var visible = false
+			var component = {
+				view: function(vnode) {
+					return visible ? {tag: "div"} : null
+				}
+			}
+			render(root, [{tag: component}])
+			visible = true
+			render(root, [{tag: component}])
+
+			o(root.firstChild.nodeName).equals("DIV")
+		})
+		o("updates from primitive", function() {
+			var visible = false
+			var component = {
+				view: function(vnode) {
+					return visible ? {tag: "div"} : false
+				}
+			}
+			render(root, [{tag: component}])
+			visible = true
+			render(root, [{tag: component}])
+
+			o(root.firstChild.nodeName).equals("DIV")
+		})
 		o("removes", function() {
 			var component = {
 				view: function(vnode) {