feature: remove diff protocol registration (#1486)

cmd/utils/flags.go

@@ -140,9 +140,8 @@ var (
 	}
 
 	DiffSyncFlag = cli.BoolFlag{
-		Name: "diffsync",
-		Usage: "Enable diffy sync, Please note that enable diffsync will improve the syncing speed, " +
-			"but will degrade the security to light client level",
+		Name:  "diffsync",
+		Usage: "warn: diff sync has been deprecated, the flag will be removed in the future",
 	}
 	PipeCommitFlag = cli.BoolFlag{
 		Name:  "pipecommit",

eth/backend.go

@@ -45,7 +45,6 @@ import (
 	"github.com/ethereum/go-ethereum/eth/filters"
 	"github.com/ethereum/go-ethereum/eth/gasprice"
 	"github.com/ethereum/go-ethereum/eth/protocols/bsc"
-	"github.com/ethereum/go-ethereum/eth/protocols/diff"
 	"github.com/ethereum/go-ethereum/eth/protocols/eth"
 	"github.com/ethereum/go-ethereum/eth/protocols/snap"
 	"github.com/ethereum/go-ethereum/eth/protocols/trust"
@@ -619,9 +618,9 @@ func (s *Ethereum) Protocols() []p2p.Protocol {
 		protos = append(protos, snap.MakeProtocols((*snapHandler)(s.handler), s.snapDialCandidates)...)
 	}
 	// diff protocol can still open without snap protocol
-	if !s.config.DisableDiffProtocol {
-		protos = append(protos, diff.MakeProtocols((*diffHandler)(s.handler), s.snapDialCandidates)...)
-	}
+	// if !s.config.DisableDiffProtocol {
+	// 	protos = append(protos, diff.MakeProtocols((*diffHandler)(s.handler), s.snapDialCandidates)...)
+	// }
 	if s.config.EnableTrustProtocol {
 		protos = append(protos, trust.MakeProtocols((*trustHandler)(s.handler), s.snapDialCandidates)...)
 	}