Properly handles possible nil values (#6042)

* handles possible nil values

slasher/db/testing/setup_db.go

@@ -27,10 +27,10 @@ func SetupSlasherDB(t testing.TB, spanCacheEnabled bool) *kv.Store {
 	}
 	cfg := &kv.Config{}
 	db, err := slasherDB.NewDB(p, cfg)
-	db.EnableSpanCache(spanCacheEnabled)
 	if err != nil {
 		t.Fatalf("Failed to instantiate DB: %v", err)
 	}
+	db.EnableSpanCache(spanCacheEnabled)
 	t.Cleanup(func() {
 		if err := db.Close(); err != nil {
 			t.Fatalf("Failed to close database: %v", err)

slasher/db/testing/setup_db_test.go

@@ -25,10 +25,10 @@ func TestClearDB(t *testing.T) {
 	}
 	cfg := &kv.Config{}
 	db, err := slasherDB.NewDB(p, cfg)
-	db.EnableSpanCache(false)
 	if err != nil {
 		t.Fatalf("Failed to instantiate DB: %v", err)
 	}
+	db.EnableSpanCache(false)
 	if err := db.ClearDB(); err != nil {
 		t.Fatal(err)
 	}

tools/enr-calculator/main.go

@@ -51,11 +51,11 @@ func main() {
 	}
 
 	db, err := enode.OpenDB("")
-	defer db.Close()
 	if err != nil {
 		log.Fatalf("Could not open node's peer database: %v\n", err)
 		return
 	}
+	defer db.Close()
 
 	localNode := enode.NewLocalNode(db, ecdsaPrivKey)
 	ipEntry := enr.IP(net.ParseIP(*ipAddr))

tools/sendDepositTx/sendDeposits.go

@@ -168,10 +168,10 @@ func main() {
 		validatorKeys := make(map[string]*prysmKeyStore.Key)
 		if randomKey {
 			validatorKey, err := prysmKeyStore.NewKey()
-			validatorKeys[hex.EncodeToString(validatorKey.PublicKey.Marshal())] = validatorKey
 			if err != nil {
 				return errors.Wrap(err, "Could not generate random key")
 			}
+			validatorKeys[hex.EncodeToString(validatorKey.PublicKey.Marshal())] = validatorKey
 		} else {
 			// Load from keystore
 			store := prysmKeyStore.NewKeystore(prysmKeystorePath)

validator/db/db.go

@@ -67,6 +67,9 @@ func createBuckets(tx *bolt.Tx, buckets ...[]byte) error {
 // and stores an open connection db object as a property of the Store struct.
 func NewKVStoreWithPublicKeyBuckets(dirPath string, pubKeys [][48]byte) (*Store, error) {
 	kv, err := NewKVStore(dirPath)
+	if err != nil {
+		return nil, err
+	}
 	// Initialize the required public keys into the DB to ensure they're not empty.
 	if err := kv.initializeSubBuckets(pubKeys); err != nil {
 		return nil, err