From 608056a34aa925a046465504a788a8f92613b9d4 Mon Sep 17 00:00:00 2001
From: Felix Lange <fjl@twurst.com>
Date: Thu, 13 Mar 2025 13:06:36 +0100
Subject: [PATCH] core/filtermaps: remove nil checks for targetView

It can never be nil.
---
 core/filtermaps/filtermaps.go      | 4 +++-
 core/filtermaps/indexer.go         | 9 +++------
 core/filtermaps/matcher_backend.go | 6 ++----
 3 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/core/filtermaps/filtermaps.go b/core/filtermaps/filtermaps.go
index af4a3d6e9f..f1be3bfaac 100644
--- a/core/filtermaps/filtermaps.go
+++ b/core/filtermaps/filtermaps.go
@@ -212,6 +212,8 @@ func NewFilterMaps(db ethdb.KeyValueStore, initView *ChainView, params Params, c
 		baseRowsCache:   lru.NewCache[uint64, [][]uint32](cachedBaseRows),
 		renderSnapshots: lru.NewCache[uint64, *renderedMap](cachedRenderSnapshots),
 	}
+
+	// Set initial indexer target.
 	f.targetView = initView
 	if f.indexedRange.initialized {
 		f.indexedView = f.initChainView(f.targetView)
@@ -314,7 +316,7 @@ func (f *FilterMaps) init() error {
 		}
 	}
 	batch := f.db.NewBatch()
-	for epoch := 0; epoch < bestLen; epoch++ {
+	for epoch := range bestLen {
 		cp := checkpoints[bestIdx][epoch]
 		f.storeLastBlockOfMap(batch, (uint32(epoch+1)<<f.logMapsPerEpoch)-1, cp.BlockNumber, cp.BlockId)
 		f.storeBlockLvPointer(batch, cp.BlockNumber, cp.FirstIndex)
diff --git a/core/filtermaps/indexer.go b/core/filtermaps/indexer.go
index 5290485c25..4f96d4660b 100644
--- a/core/filtermaps/indexer.go
+++ b/core/filtermaps/indexer.go
@@ -69,6 +69,9 @@ func (f *FilterMaps) indexerLoop() {
 // SetTargetView sets a new target chain view for the indexer to render.
 // Note that SetTargetView never blocks.
 func (f *FilterMaps) SetTargetView(targetView *ChainView) {
+	if targetView == nil {
+		panic("nil targetView")
+	}
 	for {
 		select {
 		case <-f.targetViewCh:
@@ -175,18 +178,12 @@ func (f *FilterMaps) processSingleEvent(blocking bool) bool {
 
 // setTargetView updates the target chain view of the iterator.
 func (f *FilterMaps) setTargetView(targetView *ChainView) {
-	if equalViews(f.targetView, targetView) {
-		return
-	}
 	f.targetView = targetView
 }
 
 // tryIndexHead tries to render head maps according to the current targetView
 // and returns true if successful.
 func (f *FilterMaps) tryIndexHead() bool {
-	if f.targetView == nil {
-		return false
-	}
 	headRenderer, err := f.renderMapsBefore(math.MaxUint32)
 	if err != nil {
 		log.Error("Error creating log index head renderer", "error", err)
diff --git a/core/filtermaps/matcher_backend.go b/core/filtermaps/matcher_backend.go
index 63884cdd0d..b2a294bf83 100644
--- a/core/filtermaps/matcher_backend.go
+++ b/core/filtermaps/matcher_backend.go
@@ -18,7 +18,6 @@ package filtermaps
 
 import (
 	"context"
-	"errors"
 
 	"github.com/ethereum/go-ethereum/core/types"
 )
@@ -26,6 +25,7 @@ import (
 // FilterMapsMatcherBackend implements MatcherBackend.
 type FilterMapsMatcherBackend struct {
 	f *FilterMaps
+
 	// these fields should be accessed under f.matchersLock mutex.
 	valid                 bool
 	firstValid, lastValid uint64
@@ -156,11 +156,9 @@ func (fm *FilterMapsMatcherBackend) synced() {
 // chain since the previous SyncLogIndex or the creation of the matcher backend.
 func (fm *FilterMapsMatcherBackend) SyncLogIndex(ctx context.Context) (SyncRange, error) {
 	if fm.f.noHistory {
-		if fm.f.targetView == nil {
-			return SyncRange{}, errors.New("canonical chain head not available")
-		}
 		return SyncRange{HeadNumber: fm.f.targetView.headNumber}, nil
 	}
+
 	syncCh := make(chan SyncRange, 1)
 	fm.f.matchersLock.Lock()
 	fm.syncCh = syncCh