*: fix some golint warnings (#14012)

store/tikv/client_batch.go

@@ -440,9 +440,9 @@ func (a *batchConn) batchSendLoop(cfg config.TiKVClient) {
 			return
 		} else if uint(length) < bestBatchWaitSize && bestBatchWaitSize > 1 {
 			// Waits too long to collect requests, reduce the target batch size.
-			bestBatchWaitSize -= 1
+			bestBatchWaitSize--
 		} else if uint(length) > bestBatchWaitSize+4 && bestBatchWaitSize < cfg.MaxBatchSize {
-			bestBatchWaitSize += 1
+			bestBatchWaitSize++
 		}
 
 		entries, requests = removeCanceledRequests(entries, requests)

store/tikv/snapshot_test.go

@@ -119,6 +119,8 @@ func (s *testSnapshotSuite) TestBatchGet(c *C) {
 	}
 }
 
+type contextKey string
+
 func (s *testSnapshotSuite) TestSnapshotCache(c *C) {
 	txn := s.beginTxn(c)
 	c.Assert(txn.Set(kv.Key("x"), []byte("x")), IsNil)
@@ -131,7 +133,7 @@ func (s *testSnapshotSuite) TestSnapshotCache(c *C) {
 	c.Assert(err, IsNil)
 
 	c.Assert(failpoint.Enable("github.com/pingcap/tidb/store/tikv/snapshot-get-cache-fail", `return(true)`), IsNil)
-	ctx := context.WithValue(context.Background(), "TestSnapshotCache", true)
+	ctx := context.WithValue(context.Background(), contextKey("TestSnapshotCache"), true)
 	_, err = snapshot.Get(ctx, kv.Key("x"))
 	c.Assert(err, IsNil)
 

store/tikv/txn.go

@@ -301,7 +301,7 @@ func (txn *tikvTxn) Commit(ctx context.Context) error {
 		if ctxValue != nil {
 			commitDetail := ctxValue.(**execdetails.CommitDetails)
 			if *commitDetail != nil {
-				(*commitDetail).TxnRetry += 1
+				(*commitDetail).TxnRetry++
 			} else {
 				*commitDetail = committer.getDetail()
 			}