03_messages.md

Messages

MsgSubmitEvidence

Evidence is submitted through a MsgSubmitEvidence message:

// MsgSubmitEvidence represents a message that supports submitting arbitrary
// Evidence of misbehavior such as equivocation or counterfactual signing.
message MsgSubmitEvidence {
  string              submitter = 1;
  google.protobuf.Any evidence  = 2;
}

Note, the Evidence of a MsgSubmitEvidence message must have a corresponding Handler registered with the x/evidence module's Router in order to be processed and routed correctly.

Given the Evidence is registered with a corresponding Handler, it is processed as follows:

func SubmitEvidence(ctx Context, evidence Evidence) error {
  if _, ok := GetEvidence(ctx, evidence.Hash()); ok {
    return sdkerrors.Wrap(types.ErrEvidenceExists, evidence.Hash().String())
  }
  if !router.HasRoute(evidence.Route()) {
    return sdkerrors.Wrap(types.ErrNoEvidenceHandlerExists, evidence.Route())
  }

  handler := router.GetRoute(evidence.Route())
  if err := handler(ctx, evidence); err != nil {
    return sdkerrors.Wrap(types.ErrInvalidEvidence, err.Error())
  }

  ctx.EventManager().EmitEvent(
		sdk.NewEvent(
			types.EventTypeSubmitEvidence,
			sdk.NewAttribute(types.AttributeKeyEvidenceHash, evidence.Hash().String()),
		),
	)

  SetEvidence(ctx, evidence)
  return nil
}

First, there must not already exist valid submitted Evidence of the exact same type. Secondly, the Evidence is routed to the Handler and executed. Finally, if there is no error in handling the Evidence, an event is emitted and it is persisted to state.