cmd/go: avoid creating new empty environment variables

Broke some tests that assume $GORACE is unset (because it never is).
Those tests are arguably wrong, but this is more robust.

Change-Id: Id56daa160c9e7e01f301c1386791e410bbd5deef
Reviewed-on: https://go-review.googlesource.com/6480
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

diff --git a/src/cmd/go/main.go b/src/cmd/go/main.go
index a13d990cfc3df2677733565d9803202c69eb7bd0..5e0ab79df35484723296638aeb81578466455de2 100644 (file)
--- a/src/cmd/go/main.go
+++ b/src/cmd/go/main.go
@@ -158,7 +158,9 @@ func main() {
        // but in practice there might be skew
        // This makes sure we all agree.
        for _, env := range mkEnv() {
-               os.Setenv(env.name, env.value)
+               if os.Getenv(env.name) != env.value {
+                       os.Setenv(env.name, env.value)
+               }
        }
 
        for _, cmd := range commands {