Rollback Block During Processing (#14554)

* Change it to rollback

* Spacing

* Reverse order of rollback

* Add Rollback Test

* Potuz's Test Suggestion

* Potuz's Suggestion

CHANGELOG.md

@@ -17,6 +17,7 @@ The format is based on Keep a Changelog, and this project adheres to Semantic Ve
 - Added SubmitAggregateAndProofsRequestV2 endpoint.
 - Updated the `beacon-chain/monitor` package to Electra. [PR](https://github.com/prysmaticlabs/prysm/pull/14562)
 - Added ListAttestationsV2 endpoint.
+- Add ability to rollback node's internal state during processing.
 
 ### Changed
 

beacon-chain/blockchain/process_block.go

@@ -76,6 +76,7 @@ func (s *Service) postBlockProcess(cfg *postBlockProcessConfig) error {
 
 	err := s.cfg.ForkChoiceStore.InsertNode(ctx, cfg.postState, cfg.roblock)
 	if err != nil {
+		s.rollbackBlock(ctx, cfg.roblock.Root())
 		return errors.Wrapf(err, "could not insert block %d to fork choice store", cfg.roblock.Block().Slot())
 	}
 	if err := s.handleBlockAttestations(ctx, cfg.roblock.Block(), cfg.postState); err != nil {
@@ -687,3 +688,15 @@ func (s *Service) handleInvalidExecutionError(ctx context.Context, err error, bl
 	}
 	return err
 }
+
+// In the event of an issue processing a block we rollback changes done to the db and our caches
+// to always ensure that the node's internal state is consistent.
+func (s *Service) rollbackBlock(ctx context.Context, blockRoot [32]byte) {
+	log.Warnf("Rolling back insertion of block with root %#x due to processing error", blockRoot)
+	if err := s.cfg.StateGen.DeleteStateFromCaches(ctx, blockRoot); err != nil {
+		log.WithError(err).Errorf("Could not delete state from caches with block root %#x", blockRoot)
+	}
+	if err := s.cfg.BeaconDB.DeleteBlock(ctx, blockRoot); err != nil {
+		log.WithError(err).Errorf("Could not delete block with block root %#x", blockRoot)
+	}
+}

beacon-chain/blockchain/process_block_test.go

@@ -2293,6 +2293,59 @@ func Test_getFCUArgs(t *testing.T) {
 	require.Equal(t, cfg.roblock.Root(), fcuArgs.headRoot)
 }
 
+func TestRollbackBlock(t *testing.T) {
+	service, tr := minimalTestService(t)
+	ctx := tr.ctx
+
+	st, keys := util.DeterministicGenesisState(t, 64)
+	stateRoot, err := st.HashTreeRoot(ctx)
+	require.NoError(t, err, "Could not hash genesis state")
+
+	require.NoError(t, service.saveGenesisData(ctx, st))
+
+	genesis := blocks.NewGenesisBlock(stateRoot[:])
+	wsb, err := consensusblocks.NewSignedBeaconBlock(genesis)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wsb), "Could not save genesis block")
+	parentRoot, err := genesis.Block.HashTreeRoot()
+	require.NoError(t, err, "Could not get signing root")
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, st, parentRoot), "Could not save genesis state")
+	require.NoError(t, service.cfg.BeaconDB.SaveHeadBlockRoot(ctx, parentRoot), "Could not save genesis state")
+
+	st, err = service.HeadState(ctx)
+	require.NoError(t, err)
+	b, err := util.GenerateFullBlock(st, keys, util.DefaultBlockGenConfig(), 1)
+	require.NoError(t, err)
+	wsb, err = consensusblocks.NewSignedBeaconBlock(b)
+	require.NoError(t, err)
+	root, err := b.Block.HashTreeRoot()
+	require.NoError(t, err)
+	preState, err := service.getBlockPreState(ctx, wsb.Block())
+	require.NoError(t, err)
+	postState, err := service.validateStateTransition(ctx, preState, wsb)
+	require.NoError(t, err)
+	require.NoError(t, service.savePostStateInfo(ctx, root, wsb, postState))
+
+	require.Equal(t, true, service.cfg.BeaconDB.HasBlock(ctx, root))
+	hasState, err := service.cfg.StateGen.HasState(ctx, root)
+	require.NoError(t, err)
+	require.Equal(t, true, hasState)
+
+	// Set invalid parent root to trigger forkchoice error.
+	wsb.SetParentRoot([]byte("bad"))
+	roblock, err := consensusblocks.NewROBlockWithRoot(wsb, root)
+	require.NoError(t, err)
+
+	// Rollback block insertion into db and caches.
+	require.ErrorContains(t, fmt.Sprintf("could not insert block %d to fork choice store", roblock.Block().Slot()), service.postBlockProcess(&postBlockProcessConfig{ctx, roblock, [32]byte{}, postState, false}))
+
+	// The block should no longer exist.
+	require.Equal(t, false, service.cfg.BeaconDB.HasBlock(ctx, root))
+	hasState, err = service.cfg.StateGen.HasState(ctx, root)
+	require.NoError(t, err)
+	require.Equal(t, false, hasState)
+}
+
 func fakeCommitments(n int) [][]byte {
 	f := make([][]byte, n)
 	for i := range f {