runtime: do not share underlying envs/argv array
Removes a potential data race between os.Setenv and runtime.GOROOT,
along with a bug where os.Setenv would only sometimes change the
value of runtime.GOROOT.
Change-Id: I7d2a905115c667ea6e73f349f3784a1d3e8f810d
Reviewed-on: https://go-review.googlesource.com/6611
Reviewed-by: Keith Randall <khr@golang.org>
diff --git a/src/runtime/env_test.go b/src/runtime/env_test.go
new file mode 100644
index 0000000..203f380
--- /dev/null
+++ b/src/runtime/env_test.go
@@ -0,0 +1,41 @@
+// Copyright 2015 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 runtime_test
+
+import (
+ "runtime"
+ "syscall"
+ "testing"
+)
+
+func TestFixedGOROOT(t *testing.T) {
+ if runtime.GOOS == "plan9" {
+ t.Skipf("skipping plan9, it is inconsistent by allowing GOROOT to be updated by Setenv")
+ }
+
+ envs := runtime.Envs()
+ oldenvs := append([]string{}, envs...)
+ defer runtime.SetEnvs(oldenvs)
+
+ // attempt to reuse existing envs backing array.
+ want := runtime.GOROOT()
+ runtime.SetEnvs(append(envs[:0], "GOROOT="+want))
+
+ if got := runtime.GOROOT(); got != want {
+ t.Errorf(`initial runtime.GOROOT()=%q, want %q`, got, want)
+ }
+ if err := syscall.Setenv("GOROOT", "/os"); err != nil {
+ t.Fatal(err)
+ }
+ if got := runtime.GOROOT(); got != want {
+ t.Errorf(`after setenv runtime.GOROOT()=%q, want %q`, got, want)
+ }
+ if err := syscall.Unsetenv("GOROOT"); err != nil {
+ t.Fatal(err)
+ }
+ if got := runtime.GOROOT(); got != want {
+ t.Errorf(`after unsetenv runtime.GOROOT()=%q, want %q`, got, want)
+ }
+}
