etcdserver: set txn header revision to store revision following txn

etcdserver/apply.go

@@ -229,11 +229,9 @@ func (a *applierV3backend) Range(txnID int64, r *pb.RangeRequest) (*pb.RangeResp
 }
 
 func (a *applierV3backend) Txn(rt *pb.TxnRequest) (*pb.TxnResponse, error) {
-	var revision int64
-
 	ok := true
 	for _, c := range rt.Compare {
-		if revision, ok = a.applyCompare(c); !ok {
+		if _, ok = a.applyCompare(c); !ok {
 			break
 		}
 	}
@@ -252,6 +250,8 @@ func (a *applierV3backend) Txn(rt *pb.TxnRequest) (*pb.TxnResponse, error) {
 		return nil, err
 	}
 
+	revision := a.s.KV().Rev()
+
 	// When executing the operations of txn, we need to hold the txn lock.
 	// So the reader will not see any intermediate results.
 	txnID := a.s.KV().TxnBegin()
@@ -263,11 +263,15 @@ func (a *applierV3backend) Txn(rt *pb.TxnRequest) (*pb.TxnResponse, error) {
 	}()
 
 	resps := make([]*pb.ResponseUnion, len(reqs))
+	changedKV := false
 	for i := range reqs {
+		if reqs[i].GetRequestRange() == nil {
+			changedKV = true
+		}
 		resps[i] = a.applyUnion(txnID, reqs[i])
 	}
 
-	if len(resps) != 0 {
+	if changedKV {
 		revision += 1
 	}
 

integration/v3_grpc_test.go

@@ -204,6 +204,44 @@ func TestV3TxnDuplicateKeys(t *testing.T) {
 	}
 }
 
+// Testv3TxnRevision tests that the transaction header revision is set as expected.
+func TestV3TxnRevision(t *testing.T) {
+	defer testutil.AfterTest(t)
+	clus := NewClusterV3(t, &ClusterConfig{Size: 1})
+	defer clus.Terminate(t)
+
+	kvc := toGRPC(clus.RandClient()).KV
+	pr := &pb.PutRequest{Key: []byte("abc"), Value: []byte("def")}
+	presp, err := kvc.Put(context.TODO(), pr)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	txnget := &pb.RequestUnion{Request: &pb.RequestUnion_RequestRange{RequestRange: &pb.RangeRequest{Key: []byte("abc")}}}
+	txn := &pb.TxnRequest{Success: []*pb.RequestUnion{txnget}}
+	tresp, err := kvc.Txn(context.TODO(), txn)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// did not update revision
+	if presp.Header.Revision != tresp.Header.Revision {
+		t.Fatalf("got rev %d, wanted rev %d", tresp.Header.Revision, presp.Header.Revision)
+	}
+
+	txnput := &pb.RequestUnion{Request: &pb.RequestUnion_RequestPut{RequestPut: &pb.PutRequest{Key: []byte("abc"), Value: []byte("123")}}}
+	txn = &pb.TxnRequest{Success: []*pb.RequestUnion{txnput}}
+	tresp, err = kvc.Txn(context.TODO(), txn)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// updated revision
+	if tresp.Header.Revision != presp.Header.Revision+1 {
+		t.Fatalf("got rev %d, wanted rev %d", tresp.Header.Revision, presp.Header.Revision+1)
+	}
+}
+
 // TestV3PutMissingLease ensures that a Put on a key with a bogus lease fails.
 func TestV3PutMissingLease(t *testing.T) {
 	defer testutil.AfterTest(t)