From e781303e271cd2c062d7e834927210ad529e4d7d Mon Sep 17 00:00:00 2001
From: Ken Thompson <ken@golang.org>
Date: Tue, 23 Mar 2010 13:00:02 -0700
Subject: [PATCH] maps access to a missing key will return the "zero" value

R=rsc
CC=golang-dev
https://golang.org/cl/700041
---
 src/pkg/runtime/hashmap.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/pkg/runtime/hashmap.c b/src/pkg/runtime/hashmap.c
index 281601fbc76..ccb5cfdb56d 100644
--- a/src/pkg/runtime/hashmap.c
+++ b/src/pkg/runtime/hashmap.c
@@ -769,8 +769,10 @@ void
 	av = (byte*)&h + h->vo1;
 
 	mapaccess(h, ak, av, &pres);
-	if(!pres)
-		throw("runtime.mapaccess1: key not in map");
+
+// new spec -- all elements have "zero" value
+//	if(!pres)
+//		throw("runtime.mapaccess1: key not in map");
 
 	if(debug) {
 		prints("runtime.mapaccess1: map=");