From 0c2464c497d59fbf42dcd7615e78154085ec7fcc Mon Sep 17 00:00:00 2001
From: Nishant Das <nishdas93@gmail.com>
Date: Fri, 4 Apr 2025 00:07:33 +0800
Subject: [PATCH] Handle Consolidation Processing Edge Case (#15122)

* Clean it up

* Add regression test case

* changelog
---
 beacon-chain/core/electra/consolidations.go   |  4 +-
 .../core/electra/consolidations_test.go       | 38 +++++++++++++++++++
 changelog/nisdas_handle_consolidation_bug.md  |  3 ++
 3 files changed, 43 insertions(+), 2 deletions(-)
 create mode 100644 changelog/nisdas_handle_consolidation_bug.md

diff --git a/beacon-chain/core/electra/consolidations.go b/beacon-chain/core/electra/consolidations.go
index 978b72ad1d..b239f10ba6 100644
--- a/beacon-chain/core/electra/consolidations.go
+++ b/beacon-chain/core/electra/consolidations.go
@@ -211,7 +211,7 @@ func ProcessConsolidationRequests(ctx context.Context, st state.BeaconState, req
 		if npc, err := st.NumPendingConsolidations(); err != nil {
 			return fmt.Errorf("failed to fetch number of pending consolidations: %w", err) // This should never happen.
 		} else if npc >= pcLimit {
-			return nil
+			continue
 		}
 
 		activeBal, err := helpers.TotalActiveBalance(st)
@@ -220,7 +220,7 @@ func ProcessConsolidationRequests(ctx context.Context, st state.BeaconState, req
 		}
 		churnLimit := helpers.ConsolidationChurnLimit(primitives.Gwei(activeBal))
 		if churnLimit <= primitives.Gwei(params.BeaconConfig().MinActivationBalance) {
-			return nil
+			continue
 		}
 
 		srcIdx, ok := st.ValidatorIndexByPubkey(sourcePubkey)
diff --git a/beacon-chain/core/electra/consolidations_test.go b/beacon-chain/core/electra/consolidations_test.go
index 611dda2ed9..55e54a166d 100644
--- a/beacon-chain/core/electra/consolidations_test.go
+++ b/beacon-chain/core/electra/consolidations_test.go
@@ -415,6 +415,44 @@ func TestProcessConsolidationRequests(t *testing.T) {
 				require.Equal(t, params.BeaconConfig().FarFutureEpoch, src.WithdrawableEpoch, "source validator withdrawable epoch should not be updated")
 			},
 		},
+		{
+			name: "pending consolidations limit reached and compounded consolidation after",
+			state: func() state.BeaconState {
+				st := &eth.BeaconStateElectra{
+					Slot:                  params.BeaconConfig().SlotsPerEpoch.Mul(uint64(params.BeaconConfig().ShardCommitteePeriod)),
+					Validators:            createValidatorsWithTotalActiveBalance(32000000000000000), // 32M ETH
+					PendingConsolidations: make([]*eth.PendingConsolidation, params.BeaconConfig().PendingConsolidationsLimit),
+				}
+				// To allow compounding consolidation requests.
+				st.Validators[3].WithdrawalCredentials[0] = params.BeaconConfig().ETH1AddressWithdrawalPrefixByte
+				s, err := state_native.InitializeFromProtoElectra(st)
+				require.NoError(t, err)
+				return s
+			}(),
+			reqs: []*enginev1.ConsolidationRequest{
+				{
+					SourceAddress: append(bytesutil.PadTo(nil, 19), byte(1)),
+					SourcePubkey:  []byte("val_1"),
+					TargetPubkey:  []byte("val_2"),
+				},
+				{
+					SourceAddress: append(bytesutil.PadTo(nil, 19), byte(3)),
+					SourcePubkey:  []byte("val_3"),
+					TargetPubkey:  []byte("val_3"),
+				},
+			},
+			validate: func(t *testing.T, st state.BeaconState) {
+				// Verify a pending consolidation is created.
+				numPC, err := st.NumPendingConsolidations()
+				require.NoError(t, err)
+				require.Equal(t, params.BeaconConfig().PendingConsolidationsLimit, numPC)
+
+				// Verify that the last consolidation was included
+				src, err := st.ValidatorAtIndex(3)
+				require.NoError(t, err)
+				require.Equal(t, params.BeaconConfig().CompoundingWithdrawalPrefixByte, src.WithdrawalCredentials[0], "source validator was not compounded")
+			},
+		},
 	}
 
 	for _, tt := range tests {
diff --git a/changelog/nisdas_handle_consolidation_bug.md b/changelog/nisdas_handle_consolidation_bug.md
new file mode 100644
index 0000000000..ebafddf226
--- /dev/null
+++ b/changelog/nisdas_handle_consolidation_bug.md
@@ -0,0 +1,3 @@
+### Fixed
+
+- Fixed a bug in consolidation request processing.