fix(txpipeline): keyless commands should take the slot of the keyed commands

Author: ndyakov

osscluster.go

@@ -1507,8 +1507,36 @@ func (c *ClusterClient) processTxPipeline(ctx context.Context, cmds []Cmder) err
 		return err
 	}
 
-	cmdsMap := c.mapCmdsBySlot(cmds)
+	cmdsMap := map[int][]Cmder{}
+	slot := -1
+	// split keyed and keyless commands
+	keyedCmds, _ := c.keyedAndKeyessCmds(cmds)
+	if len(keyedCmds) == 0 {
+		// no keyed commands try random slot
+		slot = hashtag.RandomSlot()
+	} else {
+		// keyed commands, get slot from them
+		// if more than one slot, return cross slot error
+		cmdsBySlot := c.mapCmdsBySlot(keyedCmds)
+		if len(cmdsBySlot) > 1 {
+			// cross slot error, we have more than one slot for keyed commands
+			setCmdsErr(cmds, ErrCrossSlot)
+			return ErrCrossSlot
+		}
+		// get the slot, should be only one
+		for sl := range cmdsBySlot {
+			slot = sl
+			break
+		}
+	}
+	// slot was not determined, try random one
+	if slot == -1 {
+		slot = hashtag.RandomSlot()
+	}
+	cmdsMap[slot] = cmds
+
 	// TxPipeline does not support cross slot transaction.
+	// double check the commands are in the same slot
 	if len(cmdsMap) > 1 {
 		setCmdsErr(cmds, ErrCrossSlot)
 		return ErrCrossSlot
@@ -1560,6 +1588,18 @@ func (c *ClusterClient) mapCmdsBySlot(cmds []Cmder) map[int][]Cmder {
 	}
 	return cmdsMap
 }
+func (c *ClusterClient) keyedAndKeyessCmds(cmds []Cmder) ([]Cmder, []Cmder) {
+	keyedCmds := make([]Cmder, 0, len(cmds))
+	keylessCmds := make([]Cmder, 0, len(cmds))
+	for _, cmd := range cmds {
+		if cmdFirstKeyPos(cmd) == 0 {
+			keylessCmds = append(keylessCmds, cmd)
+		} else {
+			keyedCmds = append(keyedCmds, cmd)
+		}
+	}
+	return keyedCmds, keylessCmds
+}
 
 func (c *ClusterClient) processTxPipelineNode(
 	ctx context.Context, node *clusterNode, cmds []Cmder, failedCmds *cmdsMap,