fix: remove error from ics27 channel ack (#751)

* removing error from channel ack in favour of event emission

* applying suggestions from PR

* Update modules/apps/27-interchain-accounts/host/keeper/events.go

Co-authored-by: Carlos Rodriguez <carlos@interchain.io>

* Update modules/apps/27-interchain-accounts/types/errors.go

Co-authored-by: Carlos Rodriguez <carlos@interchain.io>

* Update modules/apps/27-interchain-accounts/host/keeper/events.go

Co-authored-by: colin axnér <25233464+colin-axner@users.noreply.github.com>

Co-authored-by: Carlos Rodriguez <carlos@interchain.io>
Co-authored-by: colin axnér <25233464+colin-axner@users.noreply.github.com>

modules/apps/27-interchain-accounts/host/ibc_module.go

@@ -111,7 +111,10 @@ func (im IBCModule) OnRecvPacket(
 	ack := channeltypes.NewResultAcknowledgement([]byte{byte(1)})
 
 	if err := im.keeper.OnRecvPacket(ctx, packet); err != nil {
-		ack = channeltypes.NewErrorAcknowledgement(err.Error())
+		ack = channeltypes.NewErrorAcknowledgement(icatypes.AcknowledgementError)
+
+		// Emit an event including the error msg
+		keeper.EmitWriteErrorAcknowledgementEvent(ctx, packet, err)
 	}
 
 	// NOTE: acknowledgement will be written synchronously during IBC handler execution.

modules/apps/27-interchain-accounts/host/keeper/events.go

@@ -0,0 +1,20 @@
+package keeper
+
+import (
+	sdk "github.com/cosmos/cosmos-sdk/types"
+
+	"github.com/cosmos/ibc-go/v3/modules/core/exported"
+	icatypes "github.com/cosmos/ibc-go/v3/modules/apps/27-interchain-accounts/types"
+)
+
+// EmitWriteErrorAcknowledgementEvent emits an event signalling an error acknowledgement and including the error details
+func EmitWriteErrorAcknowledgementEvent(ctx sdk.Context, packet exported.PacketI, err error) {
+	ctx.EventManager().EmitEvent(
+		sdk.NewEvent(
+			icatypes.EventTypePacket,
+			sdk.NewAttribute(sdk.AttributeKeyModule, icatypes.ModuleName),
+			sdk.NewAttribute(icatypes.AttributeKeyAckError, err.Error()),
+			sdk.NewAttribute(icatypes.AttributeKeyHostChannelID, packet.GetDestChannel()),
+		),
+	)
+}

modules/apps/27-interchain-accounts/types/errors.go

@@ -4,6 +4,12 @@ import (
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 )
 
+const (
+	// AcknowledgementError defines a string constant included in error acknowledgements
+	// NOTE: Changing this const is state machine breaking as acknowledgements are written into state
+	AcknowledgementError = "error handling packet on host chain: see events for details"
+)
+
 var (
 	ErrUnknownDataType             = sdkerrors.Register(ModuleName, 2, "unknown data type")
 	ErrAccountAlreadyExist         = sdkerrors.Register(ModuleName, 3, "account already exist")

modules/apps/27-interchain-accounts/types/events.go

@@ -0,0 +1,9 @@
+package types
+
+// ICS27 Interchain Accounts events
+const (
+	EventTypePacket = "ics27_packet"
+
+	AttributeKeyAckError      = "error"
+	AttributeKeyHostChannelID = "host_channel_id"
+)