syscall: handle empty environment variable values properly on windows

Setenv("AN_ENV_VAR", "") deletes AN_ENV_VAR instead of setting it
to "" at this moment. Also Getenv("AN_ENV_VAR") returns "not found",
if AN_ENV_VAR is "". Change it, so they behave like unix.

Fixes #5610

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/10594043

diff --git a/src/pkg/syscall/env_windows.go b/src/pkg/syscall/env_windows.go
index 39bd5022efd68fdba4dcc7f9e853b57e3959dc63..420b3872464cbf5bfb05d59a21af9cfe2abffda6 100644 (file)
--- a/src/pkg/syscall/env_windows.go
+++ b/src/pkg/syscall/env_windows.go
@@ -28,20 +28,13 @@ func Getenv(key string) (value string, found bool) {
                        n = 0
                }
        }
-       if n == 0 {
-               return "", false
-       }
        return string(utf16.Decode(b[0:n])), true
 }
 
 func Setenv(key, value string) error {
-       var v *uint16
-       var err error
-       if len(value) > 0 {
-               v, err = UTF16PtrFromString(value)
-               if err != nil {
-                       return err
-               }
+       v, err := UTF16PtrFromString(value)
+       if err != nil {
+               return err
        }
        keyp, err := UTF16PtrFromString(key)
        if err != nil {

diff --git a/src/pkg/syscall/syscall_test.go b/src/pkg/syscall/syscall_test.go
new file mode 100644 (file)
index 0000000..2a39b54
--- /dev/null
+++ b/src/pkg/syscall/syscall_test.go
@@ -0,0 +1,30 @@
+// Copyright 2013 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 syscall_test
+
+import (
+       "syscall"
+       "testing"
+)
+
+func testSetGetenv(t *testing.T, key, value string) {
+       err := syscall.Setenv(key, value)
+       if err != nil {
+               t.Fatalf("Setenv failed to set %q: %v", value, err)
+       }
+       newvalue, found := syscall.Getenv(key)
+       if !found {
+               t.Fatalf("Getenv failed to find %v variable (want value %q)", key, value)
+       }
+       if newvalue != value {
+               t.Fatalf("Getenv(%v) = %q; want %q", key, newvalue, value)
+       }
+}
+
+func TestEnv(t *testing.T) {
+       testSetGetenv(t, "TESTENV", "AVALUE")
+       // make sure TESTENV gets set to "", not deleted
+       testSetGetenv(t, "TESTENV", "")
+}