Reset proposer root if the root is getting removed in store (#11053)

* Reset proposer root if the root is getting removed in store

* Potuz feedback

* Fix root

* unit test

Co-authored-by: Potuz <potuz@prysmaticlabs.com>

beacon-chain/forkchoice/doubly-linked-tree/proposer_boost_test.go

@@ -478,3 +478,21 @@ func TestForkChoice_computeProposerBoostScore(t *testing.T) {
 		require.Equal(t, uint64(8), score)
 	})
 }
+
+// Regression test (11053)
+func TestForkChoice_missingPreviousProposerBoost(t *testing.T) {
+	ctx := context.Background()
+	f := setup(1, 1)
+	balances := make([]uint64, 64) // 64 active validators.
+	for i := 0; i < len(balances); i++ {
+		balances[i] = 10
+	}
+	driftGenesisTime(f, 1, 0)
+	st, root, err := prepareForkchoiceState(ctx, 1, [32]byte{'r'}, [32]byte{}, [32]byte{}, 1, 1)
+	require.NoError(t, err)
+	require.NoError(t, f.InsertNode(ctx, st, root))
+
+	f.store.previousProposerBoostRoot = [32]byte{'p'}
+	_, err = f.Head(ctx, balances)
+	require.NoError(t, err)
+}

beacon-chain/forkchoice/doubly-linked-tree/store.go

@@ -27,15 +27,19 @@ func (s *Store) applyProposerBoostScore(newBalances []uint64) error {
 	if s.previousProposerBoostRoot != params.BeaconConfig().ZeroHash {
 		previousNode, ok := s.nodeByRoot[s.previousProposerBoostRoot]
 		if !ok || previousNode == nil {
-			return errInvalidProposerBoostRoot
+			s.previousProposerBoostRoot = [32]byte{}
+			log.WithError(errInvalidProposerBoostRoot).Errorf(fmt.Sprintf("invalid prev root %#x", s.previousProposerBoostRoot))
+			return nil
 		}
 		previousNode.balance -= s.previousProposerBoostScore
 	}
 
 	if s.proposerBoostRoot != params.BeaconConfig().ZeroHash {
 		currentNode, ok := s.nodeByRoot[s.proposerBoostRoot]
 		if !ok || currentNode == nil {
-			return errInvalidProposerBoostRoot
+			s.proposerBoostRoot = [32]byte{}
+			log.WithError(errInvalidProposerBoostRoot).Errorf(fmt.Sprintf("invalid current root %#x", s.proposerBoostRoot))
+			return nil
 		}
 		proposerScore, err = computeProposerBoostScore(newBalances)
 		if err != nil {