cmd/vet/all: exit with non-zero error code on failure

Change-Id: I68e60b155c583fa47aa5ca13d591851009a4e571
Reviewed-on: https://go-review.googlesource.com/37571Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/vet/all/main.go

@@ -24,6 +24,7 @@ import (
 	"strconv"
 	"strings"
 	"sync"
+	"sync/atomic"
 )
 
 var (
@@ -33,6 +34,7 @@ var (
 )
 
 var cmdGoPath string
+var failed uint32 // updated atomically
 
 func main() {
 	log.SetPrefix("vet/all: ")
@@ -61,6 +63,9 @@ func main() {
 	default:
 		hostPlatform.vet(runtime.GOMAXPROCS(-1))
 	}
+	if atomic.LoadUint32(&failed) != 0 {
+		os.Exit(1)
+	}
 }
 
 var hostPlatform = platform{os: build.Default.GOOS, arch: build.Default.GOARCH}
@@ -297,6 +302,7 @@ NextLine:
 			} else {
 				fmt.Fprintf(&buf, "%s:%s: %s\n", file, lineno, msg)
 			}
+			atomic.StoreUint32(&failed, 1)
 			continue
 		}
 		w[key]--
@@ -321,6 +327,7 @@ NextLine:
 				for i := 0; i < v; i++ {
 					fmt.Fprintln(&buf, k)
 				}
+				atomic.StoreUint32(&failed, 1)
 			}
 		}
 	}