What causes "input response object is nil" in hyperledger/fabric?

Check the response for nil before calling BuildStepRespone

input response object is nil

Error message

input response object is nil

What it means

BuildStepRespone converts an orderer ClusterNodeServiceStepResponse into an orderer.StepResponse. This error is thrown when the input pointer is nil, i.e. the caller passed no response object to convert. It is a defensive nil-check at the top of the public API.

Source

Thrown at orderer/common/cluster/commauth.go:329

		}
		return stepRequest, nil
	} else if subReq := request.GetSubmitRequest(); subReq != nil {
		stepRequest = &orderer.ClusterNodeServiceStepRequest{
			Payload: &orderer.ClusterNodeServiceStepRequest_NodeTranrequest{
				NodeTranrequest: &orderer.NodeTransactionOrderRequest{
					Payload:           subReq.Payload,
					LastValidationSeq: subReq.LastValidationSeq,
				},
			},
		}
		return stepRequest, nil
	}
	return nil, errors.New("service message type not valid")
}

func BuildStepRespone(stepResponse *orderer.ClusterNodeServiceStepResponse) (*orderer.StepResponse, error) {
	if stepResponse == nil {
		return nil, errors.New("input response object is nil")
	}
	if respPayload := stepResponse.GetTranorderRes(); respPayload != nil {
		stepResponse := &orderer.StepResponse{
			Payload: &orderer.StepResponse_SubmitRes{
				SubmitRes: &orderer.SubmitResponse{
					Channel: respPayload.Channel,
					Status:  respPayload.Status,
				},
			},
		}
		return stepResponse, nil
	}
	return nil, errors.New("service stream returned with invalid response type")
}

View on GitHub (pinned to 2736b63f8f)

Solutions

Check the response for nil before calling BuildStepRespone
In Recv, skip/ignore nil response messages returned from the stream before conversion
If the nil comes from unmarshalling, verify the payload bytes are valid protobuf for ClusterNodeServiceStepResponse

Example fix

// before
resp, _ := BuildStepRespone(someResp)
// after
if someResp == nil {
    return nil, errors.New("no step response received from node")
}
resp, err := BuildStepRespone(someResp)

Defensive patterns

Strategy: validation

Validate before calling

if stepResponse == nil {
    return nil, fmt.Errorf("no step response received")
}
resp, err := BuildStepRespone(stepResponse)

Type guard

func hasStepResponse(r *orderer.ClusterNodeServiceStepResponse) bool {
    return r != nil && r.GetTranorderRes() != nil
}

Try / catch

resp, err := BuildStepRespone(stepResponse)
if err != nil {
    log.Warnf("step response conversion failed: %v", err)
    return err
}

Prevention

Always nil-check grpc response messages after Recv/unmarshal before use
Return early on nil rather than dereferencing typed nil pointers
Test Recv paths with empty/nil stream messages

When it happens

Trigger: Calling BuildStepRespone(nil) directly, or Recv receiving an anonymous/grpc wrapper whose underlying response message is a nil typed pointer (e.g. a nil *ClusterNodeServiceStepResponse produced by a failed Unmarshal or empty stream message).

Common situations: A remote cluster node closed the stream or sent an empty payload; a failed proto unmarshal left the response pointer nil; unit tests invoking the converter without constructing a response.

Related errors

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/e41c44ef07f68751. Report an issue: GitHub.