chore: apply suggestions

Co-authored-by: Ryan <ryan@celestia.org>

header/p2p/exchange_test.go

@@ -106,7 +106,9 @@ func TestExchange_RequestFullRangeHeaders(t *testing.T) {
 		servers[index], err = NewExchangeServer(hosts[index], store, protocolSuffix)
 		require.NoError(t, err)
 		servers[index].Start(context.Background()) //nolint:errcheck
+		exchange.peerTracker.peerLk.Lock()
 		exchange.peerTracker.trackedPeers[hosts[index].ID()] = &peerStat{peerID: hosts[index].ID()}
+		exchange.peerTracker.peerLk.Unlock()
 	}
 
 	ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
@@ -140,13 +142,15 @@ func TestExchange_RequestHeadersFromAnotherPeer(t *testing.T) {
 	t.Cleanup(func() {
 		serverSideEx.Stop(context.Background()) //nolint:errcheck
 	})
-	// add higher score to peer that does not have the requesting range.
-	exchg.peerTracker.trackedPeers[hosts[1].ID()] = &peerStat{peerID: hosts[1].ID(), peerScore: 100}
+	exchg.peerTracker.peerLk.Lock()
 	exchg.peerTracker.trackedPeers[hosts[2].ID()] = &peerStat{peerID: hosts[2].ID(), peerScore: 20}
+	exchg.peerTracker.peerLk.Unlock()
 	_, err = exchg.GetRangeByHeight(context.Background(), 5, 3)
 	require.NoError(t, err)
+	exchg.peerTracker.peerLk.Lock()
 	// ensure that peerScore for the second peer is changed
 	newPeerScore := exchg.peerTracker.trackedPeers[hosts[2].ID()].peerScore
+	exchg.peerTracker.peerLk.Unlock()
 	require.NotEqual(t, 20, newPeerScore)
 }
 
@@ -312,6 +316,7 @@ func createP2PExAndServer(t *testing.T, host, tpeer libhost.Host) (*Exchange, *m
 	require.NoError(t, err)
 	ex, err := NewExchange(host, []peer.ID{tpeer.ID()}, "private", connGater)
 	require.NoError(t, err)
+	ex.peerTracker.trackedPeers[tpeer.ID()] = &peerStat{peerID: tpeer.ID(), peerScore: 100}
 	require.NoError(t, ex.Start(context.Background()))
 
 	t.Cleanup(func() {

header/p2p/peer_tracker.go

@@ -195,9 +195,9 @@ func (p *peerTracker) stop() {
 	}
 }
 
-// blockPeer blocks peer on the networking level and removes it from the local cache.
+// blockPeer blocks a peer on the networking level and removes it from the local cache.
 func (p *peerTracker) blockPeer(pID peer.ID) {
-	// add peer tho the blacklist, so we can't connect to it in the future.
+	// add peer to the blacklist, so we can't connect to it in the future.
 	err := p.connGater.BlockPeer(pID)
 	if err != nil {
 		log.Errorw("header/p2p: blocking peer failed", "err", err, "pID", pID)

header/p2p/session.go

@@ -31,6 +31,8 @@ type session struct {
 	// peerTracker contains discovered peers with records that describes their activity.
 	peerTracker *peerTracker
 
+	// `from` is set when additional validation for range is needed.
+	// Otherwise, it will be nil.
 	from *header.ExtendedHeader
 
 	ctx    context.Context
@@ -191,10 +193,12 @@ func (s *session) processResponse(responses []*p2p_pb.ExtendedHeaderResponse) ([
 
 // validate checks that the received range of headers is valid against the provided header.
 func (s *session) validate(headers []*header.ExtendedHeader) error {
+	// if `from` is empty, then additional validation for the header`s range is not needed.
 	if s.from == nil {
 		return nil
 	}
 
+	// verify that the first header in range is valid against the trusted header.
 	err := s.from.VerifyNonAdjacent(headers[0])
 	if err != nil {
 		return nil
@@ -205,6 +209,7 @@ func (s *session) validate(headers []*header.ExtendedHeader) error {
 	}
 
 	trusted := headers[0]
+	// verify that the whole range is valid.
 	for i := 1; i < len(headers); i++ {
 		err = trusted.VerifyAdjacent(headers[i])
 		if err != nil {