From: Shenghou Ma <minux.ma@gmail.com>
Date: Thu, 13 Dec 2012 15:48:48 +0000 (+0800)
Subject: runtime: deletion on nil maps is a no-op now
X-Git-Tag: go1.1rc2~1636
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=28a50c7f51ea031f91b47421322be981a5a0d8a6;p=gostls13.git

runtime: deletion on nil maps is a no-op now
Fixes #4535.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6942044
---

diff --git a/src/pkg/runtime/hashmap.c b/src/pkg/runtime/hashmap.c
index 60c592184e..eec5c019a8 100644
--- a/src/pkg/runtime/hashmap.c
+++ b/src/pkg/runtime/hashmap.c
@@ -989,7 +989,7 @@ runtime·mapdelete(MapType *t, Hmap *h, ...)
 	byte *ak;
 
 	if(h == nil)
-		runtime·panicstring("deletion of entry in nil map");
+		return;
 
 	if(raceenabled)
 		runtime·racewritepc(h, runtime·getcallerpc(&t), runtime·mapdelete);
diff --git a/test/fixedbugs/issue4535.go b/test/fixedbugs/issue4535.go
new file mode 100644
index 0000000000..4511393569
--- /dev/null
+++ b/test/fixedbugs/issue4535.go
@@ -0,0 +1,12 @@
+// run
+
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+func main() {
+	var m map[int]int
+	delete(m, 0)
+}