Fix data race on HermesChannel

Signed-off-by: Anton Litvinov <[email protected]>

session/pingpong/hermes_channel.go

@@ -21,27 +21,40 @@ import (
 	"math/big"
 
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/jinzhu/copier"
 	"github.com/mysteriumnetwork/node/identity"
 	"github.com/mysteriumnetwork/payments/client"
 )
 
 // NewHermesChannel creates HermesChannel model.
 func NewHermesChannel(channelID string, id identity.Identity, hermesID common.Address, channel client.ProviderChannel, promise HermesPromise, beneficiary common.Address) HermesChannel {
+
+	// in order to prevent data race over *big.Int and other referential type fileds used in hc
+	var channel_ client.ProviderChannel
+	var promise_ HermesPromise
+	if err := copier.CopyWithOption(&channel_, channel, copier.Option{DeepCopy: true}); err != nil {
+		panic(err)
+	}
+	if err := copier.CopyWithOption(&promise_, promise, copier.Option{DeepCopy: true}); err != nil {
+		panic(err)
+	}
+
 	return HermesChannel{
 		ChannelID:   channelID,
 		Identity:    id,
 		HermesID:    hermesID,
-		Channel:     channel,
-		lastPromise: promise,
+		Channel:     channel_,
+		lastPromise: promise_,
 		Beneficiary: beneficiary,
 	}
 }
 
 // HermesChannel represents opened payment channel between identity and hermes.
 type HermesChannel struct {
-	ChannelID   string
-	Identity    identity.Identity
-	HermesID    common.Address
+	ChannelID string
+	Identity  identity.Identity
+	HermesID  common.Address
+
 	Channel     client.ProviderChannel
 	lastPromise HermesPromise
 	Beneficiary common.Address