feat: allow builder only proposal flow for benefit of DVT protocols

packages/cli/src/cmds/validator/handler.ts

@@ -254,6 +254,8 @@ function parseBuilderSelection(builderSelection?: string): BuilderSelection | un
         break;
       case "builderalways":
         break;
+      case "builderonly":
+        break;
       default:
         throw Error("Invalid input for builder selection, check help.");
     }

packages/cli/src/cmds/validator/options.ts

@@ -237,7 +237,7 @@ export const validatorOptions: CliCommandOptions<IValidatorCliArgs> = {
 
   "builder.selection": {
     type: "string",
-    description: "Default builder block selection strategy: maxprofit or builderalways",
+    description: "Default builder block selection strategy: maxprofit, builderalways, or builderonly",
     defaultDescription: `${defaultOptions.builderSelection}`,
     group: "builder",
   },

packages/validator/src/services/block.ts

@@ -109,14 +109,20 @@ export class BlockProposingService {
 
       const debugLogCtx = {...logCtx, validator: pubkeyHex};
 
-      this.logger.debug("Producing block", debugLogCtx);
-      this.metrics?.proposerStepCallProduceBlock.observe(this.clock.secFromSlot(slot));
-
       const strictFeeRecipientCheck = this.validatorStore.strictFeeRecipientCheck(pubkeyHex);
       const isBuilderEnabled = this.validatorStore.isBuilderEnabled(pubkeyHex);
       const builderSelection = this.validatorStore.getBuilderSelection(pubkeyHex);
       const expectedFeeRecipient = this.validatorStore.getFeeRecipient(pubkeyHex);
 
+      this.logger.debug("Producing block", {
+        ...debugLogCtx,
+        isBuilderEnabled,
+        builderSelection,
+        expectedFeeRecipient,
+        strictFeeRecipientCheck,
+      });
+      this.metrics?.proposerStepCallProduceBlock.observe(this.clock.secFromSlot(slot));
+
       const blockContents = await this.produceBlockWrapper(slot, randaoReveal, graffiti, {
         expectedFeeRecipient,
         strictFeeRecipientCheck,
@@ -190,10 +196,20 @@ export class BlockProposingService {
   > => {
     // Start calls for building execution and builder blocks
     const blindedBlockPromise = isBuilderEnabled ? this.produceBlindedBlock(slot, randaoReveal, graffiti) : null;
-    const fullBlockPromise = this.produceBlock(slot, randaoReveal, graffiti);
+    const fullBlockPromise =
+      // At any point either the builder or execution or both flows should be active.
+      //
+      // Ideally such a scenario should be prevented on startup, but proposerSettingsFile or keymanager
+      // configurations could cause a validator pubkey to have builder disabled with builder selection builder only
+      // (TODO: independently make sure such an options update is not successful for a validator pubkey)
+      //
+      // So if builder is disabled ignore builder selection of builderonly if caused by user mistake
+      !isBuilderEnabled || builderSelection !== BuilderSelection.BuilderOnly
+        ? this.produceBlock(slot, randaoReveal, graffiti)
+        : null;
 
     let blindedBlock, fullBlock;
-    if (blindedBlockPromise !== null) {
+    if (blindedBlockPromise !== null && fullBlockPromise !== null) {
       // reference index of promises in the race
       const promisesOrder = [ProducedBlockSource.builder, ProducedBlockSource.engine];
       [blindedBlock, fullBlock] = await racePromisesWithCutoff<{
@@ -225,9 +241,16 @@ export class BlockProposingService {
         this.logger.error("Failed to produce execution block", {}, fullBlock);
         fullBlock = null;
       }
-    } else {
-      fullBlock = await fullBlockPromise;
+    } else if (blindedBlockPromise !== null && fullBlockPromise === null) {
+      blindedBlock = await blindedBlockPromise;
+      fullBlock = null;
+    } else if (blindedBlockPromise === null && fullBlockPromise !== null) {
       blindedBlock = null;
+      fullBlock = await fullBlockPromise;
+    } else {
+      throw Error(
+        `Internal Error: Neither builder nor execution proposal flow activated isBuilderEnabled=${isBuilderEnabled} builderSelection=${builderSelection}`
+      );
     }
 
     const builderBlockValue = blindedBlock?.blockValue ?? BigInt(0);
@@ -252,7 +275,7 @@ export class BlockProposingService {
           break;
         }
 
-        case BuilderSelection.BuilderAlways:
+        // For everything else just select the builder
         default: {
           selectedSource = ProducedBlockSource.builder;
           selectedBlock = blindedBlock;

packages/validator/src/services/validatorStore.ts

@@ -67,6 +67,8 @@ export type SignerRemote = {
 export enum BuilderSelection {
   BuilderAlways = "builderalways",
   MaxProfit = "maxprofit",
+  /** Only activate builder flow for DVT block proposal protocols */
+  BuilderOnly = "builderonly",
 }
 
 type DefaultProposerConfig = {