From 83a48e7bcb05ed9f179159f540b181db4dcf6e9c Mon Sep 17 00:00:00 2001
From: Noah Sloan <nsloan@spredfast.com>
Date: Tue, 2 Oct 2012 10:38:00 -0500
Subject: [PATCH] fix computes that use other computes

---
 observe/compute/compute.js      |  3 +++
 observe/compute/compute_test.js | 45 +++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+)

diff --git a/observe/compute/compute.js b/observe/compute/compute.js
index 2eee35bb5fe..17243c0700f 100644
--- a/observe/compute/compute.js
+++ b/observe/compute/compute.js
@@ -266,6 +266,9 @@ steal('can/util', function(can) {
 				if(value === undefined){
 					// we are reading
 					if(computedData){
+						if(bindings && can.Observe.__reading) {
+							can.Observe.__reading(computed,'change');
+						}
 						return computedData.value;
 					} else {
 						return getterSetter.call(context || this)
diff --git a/observe/compute/compute_test.js b/observe/compute/compute_test.js
index d7eda128e91..d9e06c71f19 100644
--- a/observe/compute/compute_test.js
+++ b/observe/compute/compute_test.js
@@ -71,3 +71,48 @@ test("setter compute", function(){
 	computed(75);
 	
 })
+
+test("compute a compute", function() {
+	var project = new can.Observe({
+		progress: 0.5
+	});
+
+	var percent = can.compute(function(val){
+		if(val) {
+			project.attr('progress', val / 100);
+		} else {
+			return parseInt( project.attr('progress') * 100, 10);
+		}
+	});
+
+	equals(percent(),50,'percent starts right');
+	percent.bind('change',function() {
+		// noop
+	});
+
+	var fraction = can.compute(function(val) {
+		if(val) {
+			percent(parseInt(val.split('/')[0],10));
+		} else {
+			return percent() + '/100';
+		}
+	});
+
+	fraction.bind('change',function() {
+		// noop
+	});
+
+	equals(fraction(),'50/100','fraction starts right');
+
+	percent(25);
+
+	equals(percent(),25);
+	equals(project.attr('progress'),0.25,'progress updated');
+	equals(fraction(),'25/100','fraction updated');
+
+	fraction('15/100');
+
+	equals(fraction(),'15/100');
+	equals(project.attr('progress'),0.15,'progress updated');
+	equals(percent(),15,'% updated');
+});