improve error messages (#203)

* improve error messages

* Update modules/light-clients/07-tendermint/types/client_state.go

Co-authored-by: Aditya <adityasripal@gmail.com>

Co-authored-by: Aditya <adityasripal@gmail.com>

Author: colin-axner

modules/core/04-channel/keeper/packet.go

@@ -471,7 +471,7 @@ func (k Keeper) AcknowledgePacket(
 	commitment := k.GetPacketCommitment(ctx, packet.GetSourcePort(), packet.GetSourceChannel(), packet.GetSequence())
 
 	if len(commitment) == 0 {
-		return sdkerrors.Wrapf(types.ErrPacketCommitmentNotFound, "packet with sequence (%d) has been acknowledged, or timed out. In rare cases the packet was never sent or the packet sequence is incorrect", packet.GetSequence())
+		return sdkerrors.Wrapf(types.ErrPacketCommitmentNotFound, "packet with sequence (%d) has been acknowledged, or timed out. In rare cases, the packet referenced was never sent, likely due to the relayer being misconfigured", packet.GetSequence())
 	}
 
 	packetCommitment := types.CommitPacket(k.cdc, packet)

modules/core/04-channel/keeper/timeout.go

@@ -81,7 +81,7 @@ func (k Keeper) TimeoutPacket(
 	commitment := k.GetPacketCommitment(ctx, packet.GetSourcePort(), packet.GetSourceChannel(), packet.GetSequence())
 
 	if len(commitment) == 0 {
-		return sdkerrors.Wrapf(types.ErrPacketCommitmentNotFound, "packet with sequence (%d) has been acknowledged or timed out. In rare cases the packet was never sent or the packet sequence is incorrect", packet.GetSequence())
+		return sdkerrors.Wrapf(types.ErrPacketCommitmentNotFound, "packet with sequence (%d) has been acknowledged or timed out. In rare cases, the packet referenced was never sent, likely due to the relayer being misconfigured", packet.GetSequence())
 	}
 
 	packetCommitment := types.CommitPacket(k.cdc, packet)

modules/light-clients/07-tendermint/types/client_state.go

@@ -568,7 +568,7 @@ func produceVerificationArgs(
 
 	consensusState, err = GetConsensusState(store, cdc, height)
 	if err != nil {
-		return commitmenttypes.MerkleProof{}, nil, err
+		return commitmenttypes.MerkleProof{}, nil, sdkerrors.Wrap(err, "please ensure the proof was constructed against a height that exists on the client")
 	}
 
 	return merkleProof, consensusState, nil