fixup: Respond to more reviewer feedback

Author: maru-ava

tests/fixture/tmpnet/network.go

@@ -28,6 +28,7 @@ import (
 	"github.com/ava-labs/avalanchego/genesis"
 	"github.com/ava-labs/avalanchego/ids"
 	"github.com/ava-labs/avalanchego/subnets"
+	"github.com/ava-labs/avalanchego/utils/constants"
 	"github.com/ava-labs/avalanchego/utils/crypto/secp256k1"
 	"github.com/ava-labs/avalanchego/utils/logging"
 	"github.com/ava-labs/avalanchego/utils/perms"
@@ -106,7 +107,7 @@ type Network struct {
 	Genesis *genesis.UnparsedConfig
 
 	// Configuration for primary subnets
-	PrimarySubnetConfigs map[ids.ID]subnets.Config
+	PrimarySubnetConfig *subnets.Config
 
 	// Configuration for primary network chains (P, X, C)
 	PrimaryChainConfigs map[string]FlagsMap
@@ -197,6 +198,9 @@ func ReadNetwork(dir string) (*Network, error) {
 	if err := network.Read(); err != nil {
 		return nil, fmt.Errorf("failed to read network: %w", err)
 	}
+	if network.DefaultFlags == nil {
+		network.DefaultFlags = FlagsMap{}
+	}
 	return network, nil
 }
 
@@ -212,17 +216,9 @@ func (n *Network) EnsureDefaultConfig(log logging.Logger, avalancheGoPath string
 		n.UUID = uuid.NewString()
 	}
 
-	// Ensure default flags
 	if n.DefaultFlags == nil {
 		n.DefaultFlags = FlagsMap{}
 	}
-	n.DefaultFlags.SetDefaults(DefaultTmpnetFlags())
-
-	if len(n.Nodes) == 1 {
-		// Sybil protection needs to be disabled for a single node network to start
-		log.Info("starting a single-node network with sybil protection disabled")
-		n.DefaultFlags[config.SybilProtectionEnabledKey] = false
-	}
 
 	// Only configure the plugin dir with a non-empty value to ensure
 	// the use of the default value (`[datadir]/plugins`) when
@@ -505,7 +501,7 @@ func (n *Network) StartNode(ctx context.Context, log logging.Logger, node *Node)
 		return err
 	}
 
-	if err := n.writeNodeFlags(node); err != nil {
+	if err := n.writeNodeFlags(log, node); err != nil {
 		return fmt.Errorf("writing node flags: %w", err)
 	}
 
@@ -769,12 +765,12 @@ func (n *Network) CreateSubnets(ctx context.Context, log logging.Logger, apiURI
 			return err
 		}
 
-		// Persist the subnet
 		if err := subnet.Write(n.GetSubnetDir()); err != nil {
 			return err
 		}
-		log.Info("wrote subnet",
+		log.Info("wrote subnet configuration",
 			zap.String("name", subnet.Name),
+			zap.Stringer("id", subnet.SubnetID),
 		)
 
 		// If one or more of the subnets chains have explicit configuration, the
@@ -877,7 +873,11 @@ func (n *Network) GetGenesisFileContent() (string, error) {
 // GetSubnetConfigContent returns the base64-encoded and
 // JSON-marshaled map of subnetID to subnet configuration.
 func (n *Network) GetSubnetConfigContent() (string, error) {
-	subnetConfigs := maps.Clone(n.PrimarySubnetConfigs)
+	subnetConfigs := map[ids.ID]subnets.Config{}
+
+	if n.PrimarySubnetConfig != nil {
+		subnetConfigs[constants.PrimaryNetworkID] = *n.PrimarySubnetConfig
+	}
 
 	// Collect configuration for non-primary subnets
 	for _, subnet := range n.Subnets {
@@ -940,22 +940,24 @@ func (n *Network) GetChainConfigContent() (string, error) {
 
 // writeNodeFlags determines the set of flags that should be used to
 // start the given node and writes them to a file in the node path.
-func (n *Network) writeNodeFlags(node *Node) error {
+func (n *Network) writeNodeFlags(log logging.Logger, node *Node) error {
 	flags := maps.Clone(node.Flags)
 
 	// Convert the network id to a string to ensure consistency in JSON round-tripping.
-	flags[config.NetworkNameKey] = strconv.FormatUint(uint64(n.GetNetworkID()), 10)
+	flags.SetDefault(config.NetworkNameKey, strconv.FormatUint(uint64(n.GetNetworkID()), 10))
 
-	// Set the network defaults
-	flags.SetDefaults(n.DefaultFlags)
+	if n.Genesis != nil && len(n.Genesis.InitialStakers) == 1 {
+		log.Info("disabling sybil protection to enable a single-node network to start")
+		flags[config.SybilProtectionEnabledKey] = false
+	}
 
 	// Set the bootstrap configuration
 	bootstrapIPs, bootstrapIDs, err := n.GetBootstrapIPsAndIDs(node)
 	if err != nil {
 		return fmt.Errorf("failed to determine bootstrap configuration: %w", err)
 	}
-	flags[config.BootstrapIDsKey] = strings.Join(bootstrapIDs, ",")
-	flags[config.BootstrapIPsKey] = strings.Join(bootstrapIPs, ",")
+	flags.SetDefault(config.BootstrapIDsKey, strings.Join(bootstrapIDs, ","))
+	flags.SetDefault(config.BootstrapIPsKey, strings.Join(bootstrapIPs, ","))
 
 	// TODO(marun) Maybe avoid computing content flags for each node start?
 
@@ -983,6 +985,10 @@ func (n *Network) writeNodeFlags(node *Node) error {
 		flags.SetDefault(config.ChainConfigContentKey, chainConfigContent)
 	}
 
+	// Set the network and tmpnet defaults last to ensure they can be overridden
+	flags.SetDefaults(n.DefaultFlags)
+	flags.SetDefaults(DefaultTmpnetFlags())
+
 	// Write the flags to disk
 	return node.writeFlags(flags)
 }

tests/fixture/tmpnet/network_config.go

@@ -11,7 +11,6 @@ import (
 	"path/filepath"
 
 	"github.com/ava-labs/avalanchego/genesis"
-	"github.com/ava-labs/avalanchego/ids"
 	"github.com/ava-labs/avalanchego/subnets"
 	"github.com/ava-labs/avalanchego/utils/crypto/secp256k1"
 	"github.com/ava-labs/avalanchego/utils/perms"
@@ -123,20 +122,20 @@ func (n *Network) readConfig() error {
 
 // The subset of network fields to store in the network config file.
 type serializedNetworkConfig struct {
-	UUID                 string
-	Owner                string
-	PrimarySubnetConfigs map[ids.ID]subnets.Config
-	PrimaryChainConfigs  map[string]FlagsMap
-	DefaultFlags         FlagsMap
-	DefaultRuntimeConfig NodeRuntimeConfig
-	PreFundedKeys        []*secp256k1.PrivateKey
+	UUID                 string                  `json:",omitempty"`
+	Owner                string                  `json:",omitempty"`
+	PrimarySubnetConfig  *subnets.Config         `json:",omitempty"`
+	PrimaryChainConfigs  map[string]FlagsMap     `json:",omitempty"`
+	DefaultFlags         FlagsMap                `json:",omitempty"`
+	DefaultRuntimeConfig NodeRuntimeConfig       `json:",omitempty"`
+	PreFundedKeys        []*secp256k1.PrivateKey `json:",omitempty"`
 }
 
 func (n *Network) writeNetworkConfig() error {
 	config := &serializedNetworkConfig{
 		UUID:                 n.UUID,
 		Owner:                n.Owner,
-		PrimarySubnetConfigs: n.PrimarySubnetConfigs,
+		PrimarySubnetConfig:  n.PrimarySubnetConfig,
 		PrimaryChainConfigs:  n.PrimaryChainConfigs,
 		DefaultFlags:         n.DefaultFlags,
 		DefaultRuntimeConfig: n.DefaultRuntimeConfig,

tests/fixture/tmpnet/network_test.go

@@ -8,7 +8,10 @@ import (
 
 	"github.com/stretchr/testify/require"
 
+	"github.com/ava-labs/avalanchego/ids"
+	"github.com/ava-labs/avalanchego/subnets"
 	"github.com/ava-labs/avalanchego/utils/logging"
+	"github.com/ava-labs/avalanchego/utils/set"
 )
 
 func TestNetworkSerialization(t *testing.T) {
@@ -17,6 +20,11 @@ func TestNetworkSerialization(t *testing.T) {
 	tmpDir := t.TempDir()
 
 	network := NewDefaultNetwork("testnet")
+	// Validate round-tripping of primary subnet configuration
+	network.PrimarySubnetConfig = &subnets.Config{
+		ValidatorOnly: true,
+		AllowedNodes:  set.Set[ids.NodeID]{},
+	}
 	require.NoError(network.EnsureDefaultConfig(logging.NoLog{}, "/path/to/avalanche/go", ""))
 	require.NoError(network.Create(tmpDir))
 	// Ensure node runtime is initialized