From 45bcb4e9ed271068bec0f678ca3c50cd45621632 Mon Sep 17 00:00:00 2001
From: Luis Carvalho <luis@volume.finance>
Date: Fri, 13 Sep 2024 10:43:32 +0100
Subject: [PATCH] chore: ignore claims behind last observed nonce (#1291)

# Related Github tickets

- https://github.com/VolumeFi/paloma/issues/2160

# Background

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.

This should prevent pigeons from getting stuck trying to get old claims
if their RPC fails, and we need to reset the nonce ahead of observed
claims.

# Testing completed

- [x] test coverage exists or has been added/updated
- [x] tested in a private testnet

# Breaking changes

- [x] I have checked my code for breaking changes
- [x] If there are breaking changes, there is a supporting migration.
---
 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) {