From c1804bee4b0bb02787afae9fe962f936c8b985a4 Mon Sep 17 00:00:00 2001
From: tiancaiamao <tiancaiamao@gmail.com>
Date: Mon, 9 Oct 2017 15:38:53 +0800
Subject: [PATCH] store/tikv/mocktikv: rpc handler should put error in response
 instead of return it

---
 store/tikv/mock-tikv/analyze.go         | 20 +++++++++++++-------
 store/tikv/mock-tikv/cop_handler_dag.go | 24 ++++++++++++++----------
 store/tikv/mock-tikv/rpc.go             |  8 ++------
 3 files changed, 29 insertions(+), 23 deletions(-)

diff --git a/store/tikv/mock-tikv/analyze.go b/store/tikv/mock-tikv/analyze.go
index c933f3c6643fc..f2eb1660bf3ec 100644
--- a/store/tikv/mock-tikv/analyze.go
+++ b/store/tikv/mock-tikv/analyze.go
@@ -27,27 +27,33 @@ import (
 	"github.com/pingcap/tipb/go-tipb"
 )
 
-func (h *rpcHandler) handleCopAnalyzeRequest(req *coprocessor.Request) (*coprocessor.Response, error) {
+func (h *rpcHandler) handleCopAnalyzeRequest(req *coprocessor.Request) *coprocessor.Response {
 	resp := &coprocessor.Response{}
 	if len(req.Ranges) == 0 {
-		return resp, nil
+		return resp
 	}
 	if req.GetTp() != kv.ReqTypeAnalyze {
-		return resp, nil
+		return resp
 	}
 	if err := h.checkRequestContext(req.GetContext()); err != nil {
 		resp.RegionError = err
-		return resp, nil
+		return resp
 	}
 	analyzeReq := new(tipb.AnalyzeReq)
 	err := proto.Unmarshal(req.Data, analyzeReq)
 	if err != nil {
-		return nil, errors.Trace(err)
+		resp.OtherError = err.Error()
+		return resp
 	}
 	if analyzeReq.Tp == tipb.AnalyzeType_TypeIndex {
-		return h.handleAnalyzeIndexReq(req, analyzeReq)
+		resp, err = h.handleAnalyzeIndexReq(req, analyzeReq)
+	} else {
+		resp, err = h.handleAnalyzeColumnsReq(req, analyzeReq)
+	}
+	if err != nil {
+		resp.OtherError = err.Error()
 	}
-	return h.handleAnalyzeColumnsReq(req, analyzeReq)
+	return resp
 }
 
 func (h *rpcHandler) handleAnalyzeIndexReq(req *coprocessor.Request, analyzeReq *tipb.AnalyzeReq) (*coprocessor.Response, error) {
diff --git a/store/tikv/mock-tikv/cop_handler_dag.go b/store/tikv/mock-tikv/cop_handler_dag.go
index 57ca00dd0710c..0abab17607056 100644
--- a/store/tikv/mock-tikv/cop_handler_dag.go
+++ b/store/tikv/mock-tikv/cop_handler_dag.go
@@ -41,23 +41,24 @@ type dagContext struct {
 	evalCtx   *evalContext
 }
 
-func (h *rpcHandler) handleCopDAGRequest(req *coprocessor.Request) (*coprocessor.Response, error) {
+func (h *rpcHandler) handleCopDAGRequest(req *coprocessor.Request) *coprocessor.Response {
 	resp := &coprocessor.Response{}
 	if len(req.Ranges) == 0 {
-		return resp, nil
+		return resp
 	}
 	if req.GetTp() != kv.ReqTypeDAG {
-		return resp, nil
+		return resp
 	}
 	if err := h.checkRequestContext(req.GetContext()); err != nil {
 		resp.RegionError = err
-		return resp, nil
+		return resp
 	}
 
 	dagReq := new(tipb.DAGRequest)
 	err := proto.Unmarshal(req.Data, dagReq)
 	if err != nil {
-		return nil, errors.Trace(err)
+		resp.OtherError = err.Error()
+		return resp
 	}
 	sc := flagsToStatementContext(dagReq.Flags)
 	timeZone := time.FixedZone("UTC", int(dagReq.TimeZoneOffset))
@@ -68,7 +69,9 @@ func (h *rpcHandler) handleCopDAGRequest(req *coprocessor.Request) (*coprocessor
 	}
 	e, err := h.buildDAG(ctx, dagReq.Executors)
 	if err != nil {
-		return nil, errors.Trace(err)
+		return &coprocessor.Response{
+			OtherError: err.Error(),
+		}
 	}
 	var (
 		chunks []tipb.Chunk
@@ -78,7 +81,7 @@ func (h *rpcHandler) handleCopDAGRequest(req *coprocessor.Request) (*coprocessor
 		var row [][]byte
 		row, err = e.Next()
 		if err != nil {
-			return nil, errors.Trace(err)
+			break
 		}
 		if row == nil {
 			break
@@ -323,7 +326,7 @@ func flagsToStatementContext(flags uint64) *variable.StatementContext {
 	return sc
 }
 
-func buildResp(chunks []tipb.Chunk, err error) (*coprocessor.Response, error) {
+func buildResp(chunks []tipb.Chunk, err error) *coprocessor.Response {
 	resp := &coprocessor.Response{}
 	selResp := &tipb.SelectResponse{
 		Error:  toPBError(err),
@@ -343,10 +346,11 @@ func buildResp(chunks []tipb.Chunk, err error) (*coprocessor.Response, error) {
 	}
 	data, err := proto.Marshal(selResp)
 	if err != nil {
-		return nil, errors.Trace(err)
+		resp.OtherError = err.Error()
+		return resp
 	}
 	resp.Data = data
-	return resp, nil
+	return resp
 }
 
 func toPBError(err error) *tipb.Error {
diff --git a/store/tikv/mock-tikv/rpc.go b/store/tikv/mock-tikv/rpc.go
index 993f3ba4147e9..36d41b8379bc9 100644
--- a/store/tikv/mock-tikv/rpc.go
+++ b/store/tikv/mock-tikv/rpc.go
@@ -581,14 +581,10 @@ func (c *RPCClient) SendReq(ctx goctx.Context, addr string, req *tikvrpc.Request
 		handler.rawStartKey = MvccKey(handler.startKey).Raw()
 		handler.rawEndKey = MvccKey(handler.endKey).Raw()
 		var res *coprocessor.Response
-		var err error
 		if r.GetTp() == kv.ReqTypeDAG {
-			res, err = handler.handleCopDAGRequest(r)
+			res = handler.handleCopDAGRequest(r)
 		} else {
-			res, err = handler.handleCopAnalyzeRequest(r)
-		}
-		if err != nil {
-			return nil, err
+			res = handler.handleCopAnalyzeRequest(r)
 		}
 		resp.Cop = res
 	case tikvrpc.CmdMvccGetByKey: