fix: make D-Chain opt-in, don't block node health

- genesis/builder: skip D-Chain if DChainGenesis is empty
- node: only mark D-Chain critical if VM plugin available
- chains/manager: non-critical chain failures don't block bootstrapped health check

Nodes can now boot with just P/X/C chains. D-Chain, Q-Chain,
and other optional VMs are loaded when their plugins are present.

Author: hanzo-dev

chains/manager.go

@@ -611,6 +611,11 @@ func (m *manager) createChain(chainParams ChainParameters) {
 			log.Err(err),
 		)
 
+		// Non-critical chain failed (e.g. D-Chain with missing VM plugin).
+		// Mark it as bootstrapped so it doesn't block the node's health check.
+		// The chain-specific health check below still reports the failure.
+		sb.Bootstrapped(chainParams.ID)
+
 		// Register the health check for this chain regardless of if it was
 		// created or not. This attempts to notify the node operator that their
 		// node may not be properly validating the net they expect to be

genesis/builder/builder.go

@@ -556,7 +556,7 @@ func FromConfig(config *genesiscfg.Config) ([]byte, ids.ID, error) {
 		}
 	}
 
-	// Specify all primary network chains
+	// Specify primary network chains (X, C always; D only if genesis provided)
 	chains := []genesis.Chain{
 		{
 			GenesisData: xvmGenesisBytes,
@@ -575,12 +575,16 @@ func FromConfig(config *genesiscfg.Config) ([]byte, ids.ID, error) {
 			VMID:        constants.EVMID,
 			Name:        "C-Chain",
 		},
-		{
+	}
+
+	// D-Chain (primary network DEX) is optional — skip if no genesis provided
+	if config.DChainGenesis != "" {
+		chains = append(chains, genesis.Chain{
 			GenesisData: getGenesis(config.DChainGenesis),
 			ChainID:     constants.PrimaryNetworkID,
 			VMID:        constants.DexVMID,
 			Name:        "D-Chain",
-		},
+		})
 	}
 
 	pChainGenesis, err := genesis.New(

node/node.go

@@ -1129,14 +1129,21 @@ func (n *Node) initChainManager(xAssetID ids.ID) error {
 		cChainID,
 	)
 
-	// D-Chain is optional — only mark critical if present in genesis
+	// D-Chain (primary network DEX) is opt-in — only critical if the VM plugin
+	// is actually available. This allows nodes to run without the DEX VM while
+	// still fully validating P/X/C chains.
 	var dChainID ids.ID
 	if optionalVMCount > 0 {
 		createDexVMTx, err := builder.VMGenesis(n.Config.GenesisBytes, constants.DexVMID)
 		if err == nil {
 			dChainID = createDexVMTx.ID()
-			criticalChains.Add(dChainID)
-			n.Log.Info("D-Chain marked as critical", "chainID", dChainID)
+			// Only mark as critical if the VM plugin is installed
+			if _, vmErr := n.VMManager.GetFactory(context.Background(), constants.DexVMID); vmErr == nil {
+				criticalChains.Add(dChainID)
+				n.Log.Info("D-Chain VM available, marked as critical", "chainID", dChainID)
+			} else {
+				n.Log.Info("D-Chain in genesis but VM not available — skipping (non-critical)", "chainID", dChainID)
+			}
 		} else {
 			n.Log.Info("D-Chain not in genesis, skipping")
 		}