From 453d4365d3226547a176fb410ff87de09bdd1aea Mon Sep 17 00:00:00 2001
From: Stefan Zermatten <stefanzermatten@gmail.com>
Date: Mon, 29 Jun 2015 09:41:01 +0200
Subject: [PATCH] Prevent memoized values being used in dependency loops

---
 rpg-docs/lib/memoize/memoize.js | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/rpg-docs/lib/memoize/memoize.js b/rpg-docs/lib/memoize/memoize.js
index 092a4036..0b98d376 100644
--- a/rpg-docs/lib/memoize/memoize.js
+++ b/rpg-docs/lib/memoize/memoize.js
@@ -15,6 +15,7 @@ function CacheObject(func, address, args, cache, context){
 	var self = this;
 	self.currentValue = null;
 	self.dep = new Tracker.Dependency();
+	self.numRun = 0;
 
 	//spawn a new autorun that keeps the value up-to-date
 	Tracker.nonreactive(function() {
@@ -26,8 +27,22 @@ function CacheObject(func, address, args, cache, context){
 				delete cache[address];
 				return;
 			}
+			//if we haven't run this before this flush, reset the counter after the flush
+			if(self.numRun === 0){
+				Tracker.afterFlush(function(){
+					self.numRun = 0;
+				});
+			}
+			self.numRun++;
 			//call the expensive function
+			//even if we don't use its value, we need to track its dependencies
 			var newValue = func.apply(context, args);
+			//prevent dependency loops, the memoized function shouldn't re-run
+			//more than once per flush
+			if (self.numRun > 1){
+				newValue = NaN;
+				if(_.isNaN(self.currentValue)) return;
+			}
 			//if the value changed, store the new value
 			if (self.currentValue !== newValue){
 				self.currentValue = newValue;