misc/dashboard/builder: use c:\ as default buildroot on windows

We have some tests (misc/cgo/test) that are disabled only because
they will fail to run on go builder - see issue 3358 for details.
This change will allow us to enable these tests.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6493118

diff --git a/misc/dashboard/builder/main.go b/misc/dashboard/builder/main.go
index 4210d88dabccb279069d3cd6a1bddcdc6dfc584e..68acb0600bb2945560952b0d4aefcfe17921847c 100644 (file)
--- a/misc/dashboard/builder/main.go
+++ b/misc/dashboard/builder/main.go
@@ -46,7 +46,7 @@ type Builder struct {
 }
 
 var (
-       buildroot     = flag.String("buildroot", filepath.Join(os.TempDir(), "gobuilder"), "Directory under which to build")
+       buildroot     = flag.String("buildroot", defaultBuildRoot(), "Directory under which to build")
        commitFlag    = flag.Bool("commit", false, "upload information about new commits")
        dashboard     = flag.String("dashboard", "build.golang.org", "Go Dashboard Host")
        buildRelease  = flag.Bool("release", false, "Build and upload binary release archives")
@@ -668,6 +668,19 @@ func defaultSuffix() string {
        return ".bash"
 }
 
+// defaultBuildRoot returns default buildroot directory.
+func defaultBuildRoot() string {
+       var d string
+       if runtime.GOOS == "windows" {
+               // will use c:\, otherwise absolute paths become too long
+               // during builder run, see http://golang.org/issue/3358.
+               d = `c:\`
+       } else {
+               d = os.TempDir()
+       }
+       return filepath.Join(d, "gobuilder")
+}
+
 func getenvOk(k string) (v string, ok bool) {
        v = os.Getenv(k)
        if v != "" {