From 1916263f6a64901b1270be1ecaf2c983ed1c8b79 Mon Sep 17 00:00:00 2001
From: Steven Allen <steven@stebalien.com>
Date: Thu, 18 Jan 2024 15:30:35 -0800
Subject: [PATCH] fix: eth: re-execute tipsets on missing events

This will re-execute tipsets to forcibly re-compute and store events
when they're missing. This is effectively lazy backfilling of events.

NOTE: This _won't_ backfill the index itself, it'll just give us the
events.

fixes #11335
---
 chain/stmgr/execute.go      | 16 ++++++++++++++--
 node/impl/full/eth.go       | 10 +---------
 node/impl/full/eth_utils.go | 24 +++++++++++++++++++++---
 3 files changed, 36 insertions(+), 14 deletions(-)

diff --git a/chain/stmgr/execute.go b/chain/stmgr/execute.go
index bed8578338b..e716ed198df 100644
--- a/chain/stmgr/execute.go
+++ b/chain/stmgr/execute.go
@@ -13,6 +13,16 @@ import (
 )
 
 func (sm *StateManager) TipSetState(ctx context.Context, ts *types.TipSet) (st cid.Cid, rec cid.Cid, err error) {
+	return sm.tipSetState(ctx, ts, false)
+}
+
+// Recompute the tipset state without trying to lookup a pre-computed result in the chainstore.
+// Useful if we know that our local chain-state isn't complete (e.g., we've discarded the events).
+func (sm *StateManager) RecomputeTipSetState(ctx context.Context, ts *types.TipSet) (st cid.Cid, rec cid.Cid, err error) {
+	return sm.tipSetState(ctx, ts, true)
+}
+
+func (sm *StateManager) tipSetState(ctx context.Context, ts *types.TipSet, recompute bool) (st cid.Cid, rec cid.Cid, err error) {
 	ctx, span := trace.StartSpan(ctx, "tipSetState")
 	defer span.End()
 	if span.IsRecordingEvents() {
@@ -65,8 +75,10 @@ func (sm *StateManager) TipSetState(ctx context.Context, ts *types.TipSet) (st c
 
 	// First, try to find the tipset in the current chain. If found, we can avoid re-executing
 	// it.
-	if st, rec, found := tryLookupTipsetState(ctx, sm.cs, ts); found {
-		return st, rec, nil
+	if !recompute {
+		if st, rec, found := tryLookupTipsetState(ctx, sm.cs, ts); found {
+			return st, rec, nil
+		}
 	}
 
 	st, rec, err = sm.tsExec.ExecuteTipSet(ctx, sm, ts, sm.tsExecMonitor, false)
diff --git a/node/impl/full/eth.go b/node/impl/full/eth.go
index d4298492f1b..deb5cae6121 100644
--- a/node/impl/full/eth.go
+++ b/node/impl/full/eth.go
@@ -422,15 +422,7 @@ func (a *EthModule) EthGetTransactionReceiptLimited(ctx context.Context, txHash
 		return nil, xerrors.Errorf("failed to convert %s into an Eth Txn: %w", txHash, err)
 	}
 
-	var events []types.Event
-	if rct := msgLookup.Receipt; rct.EventsRoot != nil {
-		events, err = a.ChainAPI.ChainGetEvents(ctx, *rct.EventsRoot)
-		if err != nil {
-			return nil, xerrors.Errorf("failed get events for %s", txHash)
-		}
-	}
-
-	receipt, err := newEthTxReceipt(ctx, tx, msgLookup, events, a.Chain, a.StateAPI)
+	receipt, err := newEthTxReceipt(ctx, tx, msgLookup, events, a.ChainAPI, a.StateAPI)
 	if err != nil {
 		return nil, xerrors.Errorf("failed to convert %s into an Eth Receipt: %w", txHash, err)
 	}
diff --git a/node/impl/full/eth_utils.go b/node/impl/full/eth_utils.go
index 5f22cea824e..90e6d054a9c 100644
--- a/node/impl/full/eth_utils.go
+++ b/node/impl/full/eth_utils.go
@@ -654,7 +654,7 @@ func newEthTxFromMessageLookup(ctx context.Context, msgLookup *api.MsgLookup, tx
 	return tx, nil
 }
 
-func newEthTxReceipt(ctx context.Context, tx ethtypes.EthTx, lookup *api.MsgLookup, events []types.Event, cs *store.ChainStore, sa StateAPI) (api.EthTxReceipt, error) {
+func newEthTxReceipt(ctx context.Context, tx ethtypes.EthTx, lookup *api.MsgLookup, ca ChainAPI, sa StateAPI) (api.EthTxReceipt, error) {
 	var (
 		transactionIndex ethtypes.EthUint64
 		blockHash        ethtypes.EthHash
@@ -695,7 +695,7 @@ func newEthTxReceipt(ctx context.Context, tx ethtypes.EthTx, lookup *api.MsgLook
 	receipt.CumulativeGasUsed = ethtypes.EmptyEthInt
 
 	// TODO: avoid loading the tipset twice (once here, once when we convert the message to a txn)
-	ts, err := cs.GetTipSetFromKey(ctx, lookup.TipSet)
+	ts, err := ca.Chain.GetTipSetFromKey(ctx, lookup.TipSet)
 	if err != nil {
 		return api.EthTxReceipt{}, xerrors.Errorf("failed to lookup tipset %s when constructing the eth txn receipt: %w", lookup.TipSet, err)
 	}
@@ -706,7 +706,7 @@ func newEthTxReceipt(ctx context.Context, tx ethtypes.EthTx, lookup *api.MsgLook
 	}
 
 	// The tx is located in the parent tipset
-	parentTs, err := cs.LoadTipSet(ctx, ts.Parents())
+	parentTs, err := ca.Chain.LoadTipSet(ctx, ts.Parents())
 	if err != nil {
 		return api.EthTxReceipt{}, xerrors.Errorf("failed to lookup tipset %s when constructing the eth txn receipt: %w", ts.Parents(), err)
 	}
@@ -731,6 +731,24 @@ func newEthTxReceipt(ctx context.Context, tx ethtypes.EthTx, lookup *api.MsgLook
 		receipt.ContractAddress = &addr
 	}
 
+	var events []types.Event
+	if rct := lookup.Receipt; rct.EventsRoot != nil {
+		events, err = ca.ChainGetEvents(ctx, *rct.EventsRoot)
+		if err != nil {
+			// Fore-recompute, we must have enabled the Event APIs after computing this
+			// tipset.
+			if _, _, err := sa.StateManager.RecomputeTipSetState(ctx, ts); err != nil {
+
+				return api.EthTxReceipt{}, xerrors.Errorf("failed get events: %w", err)
+			}
+			// Try again
+			events, err = ca.ChainGetEvents(ctx, *rct.EventsRoot)
+			if err != nil {
+				return api.EthTxReceipt{}, xerrors.Errorf("failed get events: %w", err)
+			}
+		}
+	}
+
 	if len(events) > 0 {
 		receipt.Logs = make([]ethtypes.EthLog, 0, len(events))
 		for i, evt := range events {