improve error messages for legacy rest endpoints

x/auth/client/rest/decode.go

@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"io/ioutil"
 	"net/http"
-	"strings"
 
 	"github.com/cosmos/cosmos-sdk/client"
 	clienttx "github.com/cosmos/cosmos-sdk/client/tx"
@@ -56,14 +55,9 @@ func DecodeTxRequestHandlerFn(clientCtx client.Context) http.HandlerFunc {
 
 		response := DecodeResp(stdTx)
 
-		_, err = clientCtx.LegacyAmino.MarshalJSON(response)
+		err = checkForJSONMarshalFailure(w, clientCtx, response)
 		if err != nil {
-			if strings.Contains(err.Error(), "unregistered concrete type") {
-				rest.WriteErrorResponse(w, http.StatusInternalServerError,
-					"This transaction was created with the new SIGN_MODE_DIRECT signing method, and therefore cannot be displayed"+
-						" via legacy REST handlers, please use CLI or directly query the Tendermint RPC endpoint to query"+
-						" this transaction. gRPC gateway endpoint is /cosmos/tx/v1beta1/txs/decode")
-			}
+			// Error is already returned by checkForJSONMarshalFailure.
 			return
 		}
 

x/auth/client/rest/query.go

@@ -107,14 +107,9 @@ func QueryTxsRequestHandlerFn(clientCtx client.Context) http.HandlerFunc {
 			packStdTxResponse(w, clientCtx, txRes)
 		}
 
-		_, err = clientCtx.LegacyAmino.MarshalJSON(searchResult)
+		err = checkForJSONMarshalFailure(w, clientCtx, searchResult)
 		if err != nil {
-			if strings.Contains(err.Error(), "unregistered concrete type") {
-				rest.WriteErrorResponse(w, http.StatusInternalServerError,
-					"This transaction was created with the new SIGN_MODE_DIRECT signing method, and therefore cannot be displayed"+
-						" via legacy REST handlers, please use CLI or directly query the Tendermint RPC endpoint to query"+
-						" this transaction. gRPC gateway endpoint is /cosmos/tx/v1beta1/txs")
-			}
+			// Error is already returned by checkForJSONMarshalFailure.
 			return
 		}
 
@@ -154,14 +149,9 @@ func QueryTxRequestHandlerFn(clientCtx client.Context) http.HandlerFunc {
 			rest.WriteErrorResponse(w, http.StatusNotFound, fmt.Sprintf("no transaction found with hash %s", hashHexStr))
 		}
 
-		_, err = clientCtx.LegacyAmino.MarshalJSON(output)
+		err = checkForJSONMarshalFailure(w, clientCtx, output)
 		if err != nil {
-			if strings.Contains(err.Error(), "unregistered concrete type") {
-				rest.WriteErrorResponse(w, http.StatusInternalServerError,
-					"This transaction was created with the new SIGN_MODE_DIRECT signing method, and therefore cannot be displayed"+
-						" via legacy REST handlers, please use CLI or directly query the Tendermint RPC endpoint to query"+
-						" this transaction. gRPC gateway endpoint is /cosmos/tx/v1beta1/tx/<txhash>")
-			}
+			// Error is already returned by checkForJSONMarshalFailure.
 			return
 		}
 
@@ -204,3 +194,21 @@ func packStdTxResponse(w http.ResponseWriter, clientCtx client.Context, txRes *s
 
 	return nil
 }
+
+func checkForJSONMarshalFailure(w http.ResponseWriter, ctx client.Context, resp interface{}) error {
+	// LegacyAmino used intentionally here to error message
+	const errMsg = "unregistered concrete type"
+	marshaler := ctx.LegacyAmino
+
+	_, err := marshaler.MarshalJSON(resp)
+
+	if err != nil && strings.Contains(err.Error(), errMsg) {
+		rest.WriteErrorResponse(w, http.StatusInternalServerError,
+			"This transaction was created with the new SIGN_MODE_DIRECT signing method, and therefore cannot be displayed"+
+				" via legacy REST handlers, please use CLI or directly query the Tendermint RPC endpoint to query"+
+				" this transaction.")
+		return err
+	}
+
+	return nil
+}

x/auth/client/rest/rest_test.go

@@ -338,7 +338,7 @@ func (s *IntegrationTestSuite) TestLegacyRestErrMessages() {
 		"and therefore cannot be displayed via legacy REST handlers, please use CLI or directly query the Tendermint " +
 		"RPC endpoint to query this transaction."
 
-	s.Require().Contains(errResp.Error, errMsg)
+	s.Require().Equal(errResp.Error, errMsg)
 
 	// try fetching the txn using gRPC req, it will fetch info since it has proto codec.
 	grpcJSON, err := rest.GetRequest(fmt.Sprintf("%s/cosmos/tx/v1beta1/tx/%s", val.APIAddress, txRes.TxHash))
@@ -369,7 +369,7 @@ func (s *IntegrationTestSuite) TestLegacyRestErrMessages() {
 	s.Require().NoError(err)
 
 	s.Require().NoError(val.ClientCtx.LegacyAmino.UnmarshalJSON(res, &errResp))
-	s.Require().Contains(errResp.Error, errMsg)
+	s.Require().Equal(errResp.Error, errMsg)
 }
 
 func TestIntegrationTestSuite(t *testing.T) {