From 30ae355fd1a7c81f22b805080c033b7fa8215510 Mon Sep 17 00:00:00 2001
From: Tuna <ng.tuna@gmail.com>
Date: Thu, 27 Sep 2018 10:36:40 +0700
Subject: [PATCH] adjust signed recently condition

---
 cmd/tomo/config.go     |  4 ++--
 consensus/posv/posv.go | 41 ++++++++++++++++++++++++-----------------
 2 files changed, 26 insertions(+), 19 deletions(-)

diff --git a/cmd/tomo/config.go b/cmd/tomo/config.go
index f6c6c1154249..56c95f891879 100644
--- a/cmd/tomo/config.go
+++ b/cmd/tomo/config.go
@@ -20,12 +20,12 @@ import (
 	"bufio"
 	"errors"
 	"fmt"
+	"gopkg.in/urfave/cli.v1"
 	"io"
 	"os"
 	"reflect"
-	"unicode"
 	"strings"
-	"gopkg.in/urfave/cli.v1"
+	"unicode"
 
 	"github.com/ethereum/go-ethereum/cmd/utils"
 	"github.com/ethereum/go-ethereum/dashboard"
diff --git a/consensus/posv/posv.go b/consensus/posv/posv.go
index 950ad32059d9..30e3641aacd0 100644
--- a/consensus/posv/posv.go
+++ b/consensus/posv/posv.go
@@ -575,13 +575,16 @@ func (c *Posv) verifySeal(chain consensus.ChainReader, header *types.Header, par
 			return errUnauthorized
 		}
 	}
-	for seen, recent := range snap.Recents {
-		if recent == signer {
-			// Signer is among recents, only fail if the current block doesn't shift it out
-			if limit := uint64(len(masternodes)/2 + 1); seen > number-limit {
-				// Only take into account the non-epoch blocks
-				if number%c.config.Epoch != 0 {
-					return errUnauthorized
+	if len(masternodes) > 1 {
+		for seen, recent := range snap.Recents {
+			if recent == signer {
+				// Signer is among recents, only fail if the current block doesn't shift it out
+				// There is only case that we don't allow signer to create two continuous blocks.
+				if limit := uint64(2); seen > number-limit {
+					// Only take into account the non-epoch blocks
+					if number%c.config.Epoch != 0 {
+						return errUnauthorized
+					}
 				}
 			}
 		}
@@ -755,16 +758,20 @@ func (c *Posv) Seal(chain consensus.ChainReader, block *types.Block, stop <-chan
 		}
 	}
 	// If we're amongst the recent signers, wait for the next block
-	for seen, recent := range snap.Recents {
-		if recent == signer {
-			// Signer is among recents, only wait if the current block doesn't shift it out
-			if limit := uint64(len(masternodes)/2 + 1); number < limit || seen > number-limit {
-				// Only take into account the non-epoch blocks
-				if number%c.config.Epoch != 0 {
-					log.Info("Debugging", "len(masternodes)", len(masternodes), "number", number, "limit", limit, "seen", seen, "recent", recent.String(), "snap.Recents", snap.Recents)
-					log.Info("Signed recently, must wait for others")
-					<-stop
-					return nil, nil
+	// only check recent signers if there are more than one signer.
+	if len(masternodes) > 1 {
+		for seen, recent := range snap.Recents {
+			if recent == signer {
+				// Signer is among recents, only wait if the current block doesn't shift it out
+				// There is only case that we don't allow signer to create two continuous blocks.
+				if limit := uint64(2); number < limit || seen > number-limit {
+					// Only take into account the non-epoch blocks
+					if number%c.config.Epoch != 0 {
+						log.Info("Debugging", "len(masternodes)", len(masternodes), "number", number, "limit", limit, "seen", seen, "recent", recent.String(), "snap.Recents", snap.Recents)
+						log.Info("Signed recently, must wait for others")
+						<-stop
+						return nil, nil
+					}
 				}
 			}
 		}