From b052b1ede8c36afde5ac752ab9ae11af906334a9 Mon Sep 17 00:00:00 2001
From: Luis Carvalho <luis@volume.finance>
Date: Fri, 13 Sep 2024 09:41:24 +0100
Subject: [PATCH] chore: ignore claims behind last observed nonce

If we ever reset the latest skyway nonce ahead of any observed claim, we
don't need nor want pigeons trying to attest to them. So, we can filter
claims that are behind the latest attested claim.
---
 x/skyway/keeper/attestation.go     | 13 ++++++++++-
 x/skyway/keeper/grpc_query_test.go | 35 ++++++++++++++++++++++++++++--
 2 files changed, 45 insertions(+), 3 deletions(-)

diff --git a/x/skyway/keeper/attestation.go b/x/skyway/keeper/attestation.go
index 3cf5582f..786b04e5 100644
--- a/x/skyway/keeper/attestation.go
+++ b/x/skyway/keeper/attestation.go
@@ -579,7 +579,11 @@ func (k Keeper) UnobservedBlocksByAddr(
 ) ([]uint64, error) {
 	lastCompassID := k.GetLatestCompassID(ctx, chainReferenceID)
 
-	var err error
+	lastObservedNonce, err := k.GetLastObservedSkywayNonce(ctx, chainReferenceID)
+	if err != nil {
+		return nil, err
+	}
+
 	var blocks []uint64
 
 	iterErr := k.IterateAttestations(ctx, chainReferenceID, false, func(_ []byte, att types.Attestation) bool {
@@ -602,6 +606,13 @@ func (k Keeper) UnobservedBlocksByAddr(
 			return false
 		}
 
+		// If we ever reset the latest skyway nonce ahead of any observed claim,
+		// we don't need nor want pigeons trying to attest to them. So, we can
+		// filter claims that are behind the latest attested claim.
+		if claim.GetSkywayNonce() <= lastObservedNonce {
+			return false
+		}
+
 		blocks = append(blocks, claim.GetEthBlockHeight())
 
 		return false
diff --git a/x/skyway/keeper/grpc_query_test.go b/x/skyway/keeper/grpc_query_test.go
index 0244da73..81d5e031 100644
--- a/x/skyway/keeper/grpc_query_test.go
+++ b/x/skyway/keeper/grpc_query_test.go
@@ -609,7 +609,7 @@ func TestGetUnobservedBlocksByAddr(t *testing.T) {
 			expected: nil,
 		},
 		{
-			name: "unobserved message already signed by validator",
+			name: "unobserved messages already signed by validator",
 			setup: func(ctx context.Context, k Keeper) {
 				sdkCtx := sdktypes.UnwrapSDKContext(ctx)
 
@@ -625,7 +625,7 @@ func TestGetUnobservedBlocksByAddr(t *testing.T) {
 					require.NoError(t, err)
 
 					att := &types.Attestation{
-						Observed: true,
+						Observed: false,
 						Votes:    []string{address},
 						Height:   uint64(sdkCtx.BlockHeight()),
 						Claim:    claim,
@@ -636,6 +636,37 @@ func TestGetUnobservedBlocksByAddr(t *testing.T) {
 			},
 			expected: nil,
 		},
+		{
+			name: "unobserved messages behind last observed nonce",
+			setup: func(ctx context.Context, k Keeper) {
+				sdkCtx := sdktypes.UnwrapSDKContext(ctx)
+
+				err := k.setLastObservedSkywayNonce(ctx, chainReferenceID, 2)
+				require.NoError(t, err)
+
+				for i := 0; i < 3; i++ {
+					msg := types.MsgLightNodeSaleClaim{
+						SkywayNonce:    uint64(i + 1),
+						EthBlockHeight: uint64(i + 1),
+					}
+					claim, err := codectypes.NewAnyWithValue(&msg)
+					require.NoError(t, err)
+
+					hash, err := msg.ClaimHash()
+					require.NoError(t, err)
+
+					att := &types.Attestation{
+						Observed: false,
+						Votes:    []string{},
+						Height:   uint64(sdkCtx.BlockHeight()),
+						Claim:    claim,
+					}
+
+					k.SetAttestation(ctx, chainReferenceID, uint64(i+1), hash, att)
+				}
+			},
+			expected: []uint64{3},
+		},
 		{
 			name: "unobserved messages for current and porevious compass",
 			setup: func(ctx context.Context, k Keeper) {