Merge branch 'fix/5_ready_nil_response' into 'master'

[p] Fix crash if client disconnects before ready

Fix #5 

See merge request !60

dfssc/sign/protocol.go

@@ -125,7 +125,7 @@ func (m *SignatureManager) promiseRound(pendingSet, sendSet []uint32, myID uint3
 
 	// Verifying we sent all the due promises
 	for range sendSet {
-		_ = <-c
+		<-c
 	}
 }
 

dfssp/contract/ready.go

@@ -62,10 +62,10 @@ func ReadySign(db *mgdb.MongoManager, rooms *common.WaitingGroupMap, ctx *contex
 				} // data == "" means the contractUUID is bad
 				return &api.LaunchSignature{ErrorCode: &api.ErrorCode{Code: api.ErrorCode_INVARG}}
 			}
-		case <-(*ctx).Done():
+		case <-(*ctx).Done(): // Client's disconnection
 			rooms.Unjoin(roomID, channel)
-			return nil
-		case <-time.After(10 * time.Minute):
+			return &api.LaunchSignature{ErrorCode: &api.ErrorCode{Code: api.ErrorCode_INVARG}}
+		case <-time.After(time.Minute): // Someone has not confirmed the signature within the delay
 			rooms.Unjoin(roomID, channel)
 			return &api.LaunchSignature{ErrorCode: &api.ErrorCode{Code: api.ErrorCode_TIMEOUT, Message: "timeout for ready signal"}}
 		}