cmd/go: don't write file if -n option is given

Change-Id: I01f5d3b4748d0ead8642ff3e53d1ae9c4378bcbc
Reviewed-on: https://go-review.googlesource.com/61111
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

diff --git a/src/cmd/go/internal/work/build.go b/src/cmd/go/internal/work/build.go
index d6c7f0bcff0aabd34b5e3551bba696b54e3f7dc2..0395311ef63712a31f19a5ed471e455242029a2f 100644 (file)
--- a/src/cmd/go/internal/work/build.go
+++ b/src/cmd/go/internal/work/build.go
@@ -3236,9 +3236,11 @@ func (b *Builder) gccSupportsFlag(flag string) bool {
                if cfg.BuildN || cfg.BuildX {
                        b.Showcmd(b.WorkDir, "touch trivial.c")
                }
-               src := filepath.Join(b.WorkDir, "trivial.c")
-               if err := ioutil.WriteFile(src, []byte{}, 0666); err != nil {
-                       return false
+               if !cfg.BuildN {
+                       src := filepath.Join(b.WorkDir, "trivial.c")
+                       if err := ioutil.WriteFile(src, []byte{}, 0666); err != nil {
+                               return false
+                       }
                }
                b.flagCache = make(map[string]bool)
        }