fix: nil checks

Author: minhd-vu

cmd/p2p/sensor/api.go

@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"github.com/0xPolygon/polygon-cli/p2p"
+	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/eth/protocols/eth"
 	ethp2p "github.com/ethereum/go-ethereum/p2p"
 	"github.com/prometheus/client_golang/prometheus"
@@ -33,14 +34,27 @@ type blockInfo struct {
 	Number uint64 `json:"number"`
 }
 
+// newBlockInfo creates a blockInfo from a types.Header.
+// Returns nil if the header is nil.
+func newBlockInfo(header *types.Header) *blockInfo {
+	if header == nil {
+		return nil
+	}
+
+	return &blockInfo{
+		Hash:   header.Hash().Hex(),
+		Number: header.Number.Uint64(),
+	}
+}
+
 // apiData represents all sensor information including node info and peer data.
 type apiData struct {
 	ENR       string              `json:"enr"`
 	URL       string              `json:"enode"`
 	PeerCount int                 `json:"peer_count"`
 	Peers     map[string]peerData `json:"peers"`
-	Head      blockInfo           `json:"head_block"`
-	Oldest    blockInfo           `json:"oldest_block"`
+	Head      *blockInfo          `json:"head_block"`
+	Oldest    *blockInfo          `json:"oldest_block"`
 }
 
 // handleAPI sets up the API for interacting with the sensor. All endpoints
@@ -82,19 +96,18 @@ func handleAPI(server *ethp2p.Server, counter *prometheus.CounterVec, conns *p2p
 		head := conns.HeadBlock()
 		oldest := conns.OldestBlock()
 
+		var headHeader *types.Header
+		if head.Block != nil {
+			headHeader = head.Block.Header()
+		}
+
 		data := apiData{
 			ENR:       server.NodeInfo().ENR,
 			URL:       server.Self().URLv4(),
 			PeerCount: len(peers),
 			Peers:     peers,
-			Head: blockInfo{
-				Hash:   head.Block.Hash().Hex(),
-				Number: head.Block.NumberU64(),
-			},
-			Oldest: blockInfo{
-				Hash:   oldest.Hash().Hex(),
-				Number: oldest.Number.Uint64(),
-			},
+			Head:      newBlockInfo(headHeader),
+			Oldest:    newBlockInfo(oldest),
 		}
 
 		if err := json.NewEncoder(w).Encode(data); err != nil {

p2p/metrics.go

@@ -58,7 +58,7 @@ func NewBlockMetrics(block *types.Block) *BlockMetrics {
 
 // Update updates all block metrics.
 func (m *BlockMetrics) Update(block *types.Block, oldest *types.Header) {
-	if m == nil {
+	if m == nil || block == nil || oldest == nil {
 		return
 	}
 

p2p/protocol.go

@@ -311,6 +311,9 @@ func (c *conn) getParentBlock(ctx context.Context, header *types.Header) error {
 	}
 
 	oldestBlock := c.conns.OldestBlock()
+	if oldestBlock == nil {
+		return nil
+	}
 
 	// Check cache first before querying the database
 	cache, ok := c.conns.Blocks().Peek(header.ParentHash)