Travis: add staticcheck (#1019)

Also only run golint and go vet in Go 1.8, and fix some vet failures.

.travis.yml

@@ -1,19 +1,20 @@
 language: go
 
 go:
-  - 1.6.3
-  - 1.7
-  - 1.8
+  - 1.6.x
+  - 1.7.x
+  - 1.8.x
 
 go_import_path: google.golang.org/grpc
 
 before_install:
-  - go get github.com/golang/lint/golint
+  - if [[ $TRAVIS_GO_VERSION = 1.8* ]]; then go get -u github.com/golang/lint/golint honnef.co/go/tools/cmd/staticcheck; fi
   - go get -u golang.org/x/tools/cmd/goimports github.com/axw/gocov/gocov github.com/mattn/goveralls golang.org/x/tools/cmd/cover
 
 script:
   - '! gofmt -s -d -l . 2>&1 | read'
   - '! goimports -l . | read'
-  - '! golint ./... | grep -vE "(_mock|_string|\.pb)\.go:"'
-  - '! go tool vet -all . 2>&1 | grep -vE "constant [0-9]+ not a string in call to Errorf" | grep -vF .pb.go:' # https://github.com/golang/protobuf/issues/214
+  - 'if [[ $TRAVIS_GO_VERSION = 1.8* ]]; then ! golint ./... | grep -vE "(_mock|_string|\.pb)\.go:"; fi'
+  - 'if [[ $TRAVIS_GO_VERSION = 1.8* ]]; then ! go tool vet -all . 2>&1 | grep -vF .pb.go:; fi' # https://github.com/golang/protobuf/issues/214
   - make test testrace
+  - 'if [[ $TRAVIS_GO_VERSION = 1.8* ]]; then staticcheck -ignore google.golang.org/grpc/transport/transport_test.go:SA2002 ./...; fi' # TODO(menghanl): fix these

benchmark/benchmark_test.go

@@ -73,7 +73,7 @@ func runStream(b *testing.B, maxConcurrentCalls int) {
 		streamCaller(stream)
 	}
 
-	ch := make(chan int, maxConcurrentCalls*4)
+	ch := make(chan struct{}, maxConcurrentCalls*4)
 	var (
 		mu sync.Mutex
 		wg sync.WaitGroup
@@ -82,11 +82,11 @@ func runStream(b *testing.B, maxConcurrentCalls int) {
 
 	// Distribute the b.N calls over maxConcurrentCalls workers.
 	for i := 0; i < maxConcurrentCalls; i++ {
-		go func() {
 		stream, err := tc.StreamingCall(context.Background())
 		if err != nil {
 			b.Fatalf("%v.StreamingCall(_) = _, %v", tc, err)
 		}
+		go func() {
 			for range ch {
 				start := time.Now()
 				streamCaller(stream)
@@ -100,7 +100,7 @@ func runStream(b *testing.B, maxConcurrentCalls int) {
 	}
 	b.StartTimer()
 	for i := 0; i < b.N; i++ {
-		ch <- i
+		ch <- struct{}{}
 	}
 	b.StopTimer()
 	close(ch)

clientconn_test.go

@@ -295,17 +295,20 @@ func (b *emptyBalancer) Close() error {
 
 func TestNonblockingDialWithEmptyBalancer(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
-	dialDone := make(chan struct{})
+	defer cancel()
+	dialDone := make(chan error)
 	go func() {
+		dialDone <- func() error {
 			conn, err := DialContext(ctx, "Non-Existent.Server:80", WithInsecure(), WithBalancer(newEmptyBalancer()))
 			if err != nil {
-			t.Fatalf("unexpected error dialing connection: %v", err)
+				return err
 			}
-		conn.Close()
-		close(dialDone)
+			return conn.Close()
 		}()
-	<-dialDone
-	cancel()
+	}()
+	if err := <-dialDone; err != nil {
+		t.Fatalf("unexpected error dialing connection: %s", err)
+	}
 }
 
 func TestClientUpdatesParamsAfterGoAway(t *testing.T) {

server.go

@@ -690,7 +690,6 @@ func (s *Server) processUnaryRPC(t transport.ServerTransport, stream *transport.
 		stream.SetSendCompress(s.opts.cp.Type())
 	}
 	p := &parser{r: stream}
-	for { // TODO: delete
 	pf, req, err := p.recvMsg(s.opts.maxMsgSize)
 	if err == io.EOF {
 		// The entire stream is done (for unary RPC only).
@@ -823,7 +822,6 @@ func (s *Server) processUnaryRPC(t transport.ServerTransport, stream *transport.
 	// error or allow the stats handler to see it?
 	return t.WriteStatus(stream, status.New(codes.OK, ""))
 }
-}
 
 func (s *Server) processStreamingRPC(t transport.ServerTransport, stream *transport.Stream, srv *service, sd *StreamDesc, trInfo *traceInfo) (err error) {
 	sh := s.opts.statsHandler

test/end2end_test.go

@@ -2423,8 +2423,8 @@ func testMetadataStreamingRPC(t *testing.T, e env) {
 		if err != nil || !reflect.DeepEqual(testMetadata, headerMD) {
 			t.Errorf("#2 %v.Header() = %v, %v, want %v, <nil>", stream, headerMD, err, testMetadata)
 		}
-		var index int
-		for index < len(reqSizes) {
+		err = func() error {
+			for index := 0; index < len(reqSizes); index++ {
 				respParam := []*testpb.ResponseParameters{
 					{
 						Size: proto.Int32(int32(respSizes[index])),
@@ -2433,7 +2433,7 @@ func testMetadataStreamingRPC(t *testing.T, e env) {
 
 				payload, err := newPayload(testpb.PayloadType_COMPRESSABLE, int32(reqSizes[index]))
 				if err != nil {
-				t.Fatal(err)
+					return err
 				}
 
 				req := &testpb.StreamingOutputCallRequest{
@@ -2442,13 +2442,16 @@ func testMetadataStreamingRPC(t *testing.T, e env) {
 					Payload:            payload,
 				}
 				if err := stream.Send(req); err != nil {
-				t.Errorf("%v.Send(%v) = %v, want <nil>", stream, req, err)
-				return
+					return fmt.Errorf("%v.Send(%v) = %v, want <nil>", stream, req, err)
 				}
-			index++
 			}
+			return nil
+		}()
 		// Tell the server we're done sending args.
 		stream.CloseSend()
+		if err != nil {
+			t.Error(err)
+		}
 	}()
 	for {
 		if _, err := stream.Recv(); err != nil {
@@ -2844,7 +2847,8 @@ func testStreamsQuotaRecovery(t *testing.T, e env) {
 			defer wg.Done()
 			payload, err := newPayload(testpb.PayloadType_COMPRESSABLE, 314)
 			if err != nil {
-				t.Fatal(err)
+				t.Error(err)
+				return
 			}
 			req := &testpb.SimpleRequest{
 				ResponseType: testpb.PayloadType_COMPRESSABLE.Enum(),