multi: fix non-constant input of fmt.Errorf

Fixed multiple cases in which a non-constact string variable was used as a
format string for fmt.Errorf.

chanacceptor/rpcacceptor.go

@@ -548,7 +548,7 @@ func (r *RPCAcceptor) validateAcceptorResponse(dustLimit btcutil.Amount,
 
 	// If we reject the channel, and have a custom error, then we use it.
 	case haveCustomError:
-		return false, fmt.Errorf(req.Error), nil, nil
+		return false, fmt.Errorf("%s", req.Error), nil, nil
 
 	// Otherwise, we have rejected the channel with no custom error, so we
 	// just use a generic error to fail the channel.

channeldb/migration_01_to_11/zpay32/bech32.go

@@ -76,7 +76,8 @@ func decodeBech32(bech string) (string, []byte, error) {
 			moreInfo = fmt.Sprintf("Expected %v, got %v.",
 				expected, checksum)
 		}
-		return "", nil, fmt.Errorf("checksum failed. " + moreInfo)
+
+		return "", nil, fmt.Errorf("checksum failed. %s", moreInfo)
 	}
 
 	// We exclude the last 6 bytes, which is the checksum.

macaroons/constraints.go

@@ -136,7 +136,8 @@ func IPLockChecker() (string, checkers.Func) {
 		// check.
 		pr, ok := peer.FromContext(ctx)
 		if !ok {
-			return fmt.Errorf("unable to get peer info from context")
+			return fmt.Errorf("unable to get peer info from " +
+				"context")
 		}
 		peerAddr, _, err := net.SplitHostPort(pr.Addr.String())
 		if err != nil {
@@ -144,8 +145,8 @@ func IPLockChecker() (string, checkers.Func) {
 		}
 
 		if !net.ParseIP(arg).Equal(net.ParseIP(peerAddr)) {
-			msg := "macaroon locked to different IP address"
-			return fmt.Errorf(msg)
+			return fmt.Errorf("macaroon locked to different IP " +
+				"address")
 		}
 		return nil
 	}

rpcserver.go

@@ -7986,7 +7986,7 @@ func (r *rpcServer) UpdateChannelPolicy(ctx context.Context,
 		errMsg := "cannot set both FeeRate and FeeRatePpm at the " +
 			"same time"
 
-		return nil, status.Errorf(codes.InvalidArgument, errMsg)
+		return nil, status.Errorf(codes.InvalidArgument, "%v", errMsg)
 
 	// If the request is using fee_rate.
 	case req.FeeRate != 0:

zpay32/bech32.go

@@ -76,7 +76,8 @@ func decodeBech32(bech string) (string, []byte, error) {
 			moreInfo = fmt.Sprintf("Expected %v, got %v.",
 				expected, checksum)
 		}
-		return "", nil, fmt.Errorf("checksum failed. " + moreInfo)
+
+		return "", nil, fmt.Errorf("checksum failed. %s", moreInfo)
 	}
 
 	// We exclude the last 6 bytes, which is the checksum.