From 54d7bd9a2131ea5139f0be93fae888e40dcd326d Mon Sep 17 00:00:00 2001
From: Alex Sharov <AskAlexSharov@gmail.com>
Date: Tue, 22 Oct 2024 10:15:51 +0700
Subject: [PATCH] `RecentLogs` prevent grow over `limit` (#12386)

---
 turbo/shards/events.go      | 21 ++++++++++++--
 turbo/shards/events_test.go | 55 +++++++++++++++++++++++++++++++++++++
 2 files changed, 74 insertions(+), 2 deletions(-)
 create mode 100644 turbo/shards/events_test.go

diff --git a/turbo/shards/events.go b/turbo/shards/events.go
index dff2c7e8c12..53a1b19b18c 100644
--- a/turbo/shards/events.go
+++ b/turbo/shards/events.go
@@ -243,11 +243,28 @@ func (r *RecentLogs) Add(receipts types.Receipts) {
 	}
 	r.mu.Lock()
 	defer r.mu.Unlock()
+	var blockNum uint64
+	var ok bool
 	// find non-nil receipt
 	for _, receipt := range receipts {
 		if receipt != nil {
-			r.receipts[receipts[0].BlockNumber.Uint64()] = receipts
-			return
+			ok = true
+			blockNum = receipt.BlockNumber.Uint64()
+			break
+		}
+	}
+	if !ok {
+		return
+	}
+	r.receipts[blockNum] = receipts
+
+	//enforce `limit`: drop all items older than `limit` blocks
+	if len(r.receipts) <= int(r.limit) {
+		return
+	}
+	for bn := range r.receipts {
+		if bn+r.limit < blockNum {
+			delete(r.receipts, bn)
 		}
 	}
 }
diff --git a/turbo/shards/events_test.go b/turbo/shards/events_test.go
new file mode 100644
index 00000000000..356d37b5b4f
--- /dev/null
+++ b/turbo/shards/events_test.go
@@ -0,0 +1,55 @@
+// Copyright 2024 The Erigon Authors
+// This file is part of Erigon.
+//
+// Erigon is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Erigon is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with Erigon. If not, see <http://www.gnu.org/licenses/>.
+
+package shards
+
+import (
+	"math/big"
+	"testing"
+
+	"github.com/erigontech/erigon/core/types"
+	"github.com/stretchr/testify/require"
+)
+
+func TestRecentLogs(t *testing.T) {
+	t.Parallel()
+	t.Run("Evict", func(t *testing.T) {
+		e := NewRecentLogs(3)
+		e.Add(types.Receipts{{BlockNumber: big.NewInt(1)}})
+		e.Add(types.Receipts{{BlockNumber: big.NewInt(11)}})
+		e.Add(types.Receipts{{BlockNumber: big.NewInt(21)}})
+		require.Equal(t, 3, len(e.receipts))
+
+		e.Add(types.Receipts{{BlockNumber: big.NewInt(31)}})
+		require.Equal(t, 1, len(e.receipts))
+	})
+	t.Run("Nil", func(t *testing.T) {
+		e := NewRecentLogs(3)
+		e.Add(types.Receipts{nil, {BlockNumber: big.NewInt(1)}})
+		e.Add(types.Receipts{{BlockNumber: big.NewInt(21)}, nil})
+		e.Add(types.Receipts{nil, nil, {BlockNumber: big.NewInt(31)}})
+		require.Equal(t, 3, len(e.receipts))
+	})
+	t.Run("Order", func(t *testing.T) {
+		e := NewRecentLogs(3)
+		e.Add(types.Receipts{{BlockNumber: big.NewInt(1)}})
+		e.Add(types.Receipts{{BlockNumber: big.NewInt(11)}})
+		e.Add(types.Receipts{{BlockNumber: big.NewInt(1)}})
+		require.Equal(t, 2, len(e.receipts))
+		e.Add(types.Receipts{{BlockNumber: big.NewInt(11)}})
+		require.Equal(t, 2, len(e.receipts))
+	})
+}