fix: Overhaul the max ack gas loss

config.example.yaml

@@ -21,10 +21,12 @@ global:
     # Evaluation properties
     evaluationRetryInterval: 3600000    # Interval at which to reevaluate whether to relay a message.
     maxEvaluationDuration: 86400000     # Time after which to drop an undelivered message.
-    unrewardedDeliveryGas: '100000'     # Gas amount that will be unrewarded on delivery submission.
+    verificationDeliveryGas: '55000'    # Gas amount used for packet verification upon delivery.
+    unrewardedDeliveryGas: '25000'      # Gas amount that will be unrewarded on delivery submission.
     minDeliveryReward: 0.001            # In the 'pricingDenomination' specified below
     relativeMinDeliveryReward: 0.001
-    unrewardedAckGas: '50000'           # Gas amount that will be unrewarded on ack submission.
+    verificationAckGas: '55000'         # Gas amount used for packet verification upon ack.
+    unrewardedAckGas: '25000'           # Gas amount that will be unrewarded on ack submission.
     minAckReward: 0.001                 # In the 'pricingDenomination' specified below
     relativeMinAckReward: 0.001
     profitabilityFactor: 1.0            # Profitiability evaluation adjustment factor. A larger

src/config/config.schema.ts

@@ -150,9 +150,11 @@ const SUBMITTER_SCHEMA = {
         evaluationRetryInterval: { $ref: "positive-number-schema" },
         maxEvaluationDuration: { $ref: "positive-number-schema" },
         unrewardedDeliveryGas: { $ref: "gas-field-schema" },
+        verificationDeliveryGas: { $ref: "gas-field-schema" },
         minDeliveryReward: { $ref: "positive-number-schema" },
         relativeMinDeliveryReward: { $ref: "positive-number-schema" },
         unrewardedAckGas: { $ref: "gas-field-schema" },
+        verificationAckGas: { $ref: "gas-field-schema" },
         minAckReward: { $ref: "positive-number-schema" },
         relativeMinAckReward: { $ref: "positive-number-schema" },
         profitabilityFactor: { $ref: "positive-number-schema" },

src/config/config.service.ts

@@ -191,9 +191,15 @@ export class ConfigService {
         if (config.unrewardedDeliveryGas != undefined) {
             config.unrewardedDeliveryGas = BigInt(config.unrewardedDeliveryGas);
         }
+        if (config.verificationDeliveryGas != undefined) {
+            config.verificationDeliveryGas = BigInt(config.verificationDeliveryGas);
+        }
         if (config.unrewardedAckGas != undefined) {
             config.unrewardedAckGas = BigInt(config.unrewardedAckGas);
         }
+        if (config.verificationAckGas != undefined) {
+            config.verificationAckGas = BigInt(config.verificationAckGas);
+        }
         return config as SubmitterGlobalConfig;
     }
 

src/config/config.types.ts

@@ -48,9 +48,11 @@ export interface SubmitterGlobalConfig {
   evaluationRetryInterval?: number;
   maxEvaluationDuration?: number;
   unrewardedDeliveryGas?: bigint;
+  verificationDeliveryGas?: bigint;
   minDeliveryReward?: number;
   relativeMinDeliveryReward?: number;
   unrewardedAckGas?: bigint;
+  verificationAckGas?: bigint;
   minAckReward?: number;
   relativeMinAckReward?: number;
   profitabilityFactor?: number;

src/submitter/queues/eval-queue.ts

@@ -230,12 +230,10 @@ export class EvalQueue extends ProcessingQueue<EvalOrder, SubmitOrder> {
             bounty.priceOfDeliveryGas
         );
 
-        // Consider the worst 'ack' submission loss, as in that case no one will desire to submit
-        // the 'ack', and this relayer will have to submit it in order to get the payment for the
-        // delivery.
         const maxAckLoss = this.calcMaxGasLoss(             // ! In source chain gas value
             sourceGasPrice,
             this.evaluationConfig.unrewardedAckGas,
+            this.evaluationConfig.verificationAckGas,
             BigInt(bounty.maxGasAck),
             bounty.priceOfAckGas,
         );
@@ -248,7 +246,7 @@ export class EvalQueue extends ProcessingQueue<EvalOrder, SubmitOrder> {
             this.chainId
         );
 
-        const correctedDeliveryReward = deliveryReward - maxAckLoss;
+        const correctedDeliveryReward = deliveryReward + maxAckLoss;
         const deliveryFiatReward = await this.getGasCostFiatPrice(
             correctedDeliveryReward,
             bounty.fromChainId
@@ -399,24 +397,42 @@ export class EvalQueue extends ProcessingQueue<EvalOrder, SubmitOrder> {
     private calcMaxGasLoss(
         gasPrice: bigint,
         unrewardedGas: bigint,
+        verificationGas: bigint,
         bountyMaxGas: bigint,
         bountyPriceOfGas: bigint,
     ): bigint {
-        // Evaluate the worst possible loss of a submission. There are 2 possible scenarios:
-        //   - The provided `bountyPriceOfGas` covers the current gas price: the worst loss
-        //     will occur if no gas is used for the submission logic (and hence there is no bounty 
-        //     reward).
-        //   - The provided `bountyPriceOfGas' does *not* cover the current gas price: the 
-        //     worst loss will occur if the maximum allowed amount of gas is used for the 
-        //     submission logic.
-
-        const fixedCost = unrewardedGas * gasPrice;
-
-        const worstCaseVariableCost = gasPrice > bountyPriceOfGas
-            ? bountyMaxGas * (gasPrice - bountyPriceOfGas)
-            : 0n;
 
-        return fixedCost + worstCaseVariableCost;
+        // The gas used for the 'ack' submission is composed of 3 amounts:
+        //   - Logic overhead: is never computed for the reward.
+        //   - Verification logic: is only computed for the reward if the source application's
+        //     'ack' handler does not use all of the 'ack' gas allowance ('bountyMaxGas').
+        //   - Source application's 'ack' handler: it is always computed for the reward (up to a
+        //     maximum of 'bountyMaxGas').
+
+        // Evaluate the minimum expected profit from the 'ack' delivery. There are 2 possible
+        // scenarios:
+        //   - No gas is used by the source application's 'ack' handler.
+        //   - The maximum allowed amount of gas is used by the source application's 'ack' handler.
+
+        // NOTE: strictly speaking, 'verificationGas' should be upperbounded by 'bountyMaxGas' on
+        // the following line. However, this is not necessary, as in such a case
+        // 'maximumGasUsageProfit' will always return a smaller profit than 'minimumGasUsageProfit'.
+        const minimumGasUsageReward = verificationGas * bountyPriceOfGas;
+        const minimumGasUsageCost = (unrewardedGas + verificationGas) * gasPrice;
+        const minimumGasUsageProfit = minimumGasUsageReward - minimumGasUsageCost;
+
+        const maximumGasUsageReward = bountyMaxGas * bountyPriceOfGas;
+        const maximumGasUsageCost = (unrewardedGas + verificationGas + bountyMaxGas) * gasPrice;
+        const maximumGasUsageProfit = maximumGasUsageReward - maximumGasUsageCost;
+
+        const worstCaseProfit =  minimumGasUsageProfit < maximumGasUsageProfit
+            ? minimumGasUsageProfit
+            : maximumGasUsageProfit;
+
+        // Only return the 'worstCaseProfit' if it's negative.
+        return worstCaseProfit < 0n
+            ? worstCaseProfit
+            : 0n;
     }
 
     private async getGasPrice(chainId: string): Promise<bigint> {

src/submitter/submitter.service.ts

@@ -18,9 +18,11 @@ const NEW_ORDERS_DELAY_DEFAULT = 0;
 const EVALUATION_RETRY_INTERVAL_DEFAULT = 60 * 60 * 1000;
 const MAX_EVALUATION_DURATION_DEFAULT = 24 * 60 * 60 * 1000;
 const UNREWARDED_DELIVERY_GAS_DEFAULT = 0n;
+const VERIFICATION_DELIVERY_GAS_DEFAULT = 0n;
 const MIN_DELIVERY_REWARD_DEFAULT = 0;
 const RELATIVE_MIN_DELIVERY_REWARD_DEFAULT = 0;
 const UNREWARDED_ACK_GAS_DEFAULT = 0n;
+const VERIFICATION_ACK_GAS_DEFAULT = 0n;
 const MIN_ACK_REWARD_DEFAULT = 0;
 const RELATIVE_MIN_ACK_REWARD_DEFAULT = 0;
 const PROFITABILITY_FACTOR_DEFAULT = 1;
@@ -35,9 +37,11 @@ interface GlobalSubmitterConfig {
     evaluationRetryInterval: number;
     maxEvaluationDuration: number;
     unrewardedDeliveryGas: bigint;
+    verificationDeliveryGas: bigint;
     minDeliveryReward: number;
     relativeMinDeliveryReward: number;
     unrewardedAckGas: bigint;
+    verificationAckGas: bigint;
     minAckReward: number;
     relativeMinAckReward: number;
     profitabilityFactor: number;
@@ -57,9 +61,11 @@ export interface SubmitterWorkerData {
     evaluationRetryInterval: number;
     maxEvaluationDuration: number;
     unrewardedDeliveryGas: bigint;
+    verificationDeliveryGas: bigint;
     minDeliveryReward: number;
     relativeMinDeliveryReward: number;
     unrewardedAckGas: bigint;
+    verificationAckGas: bigint;
     minAckReward: number;
     relativeMinAckReward: number;
     profitabilityFactor: number;
@@ -147,12 +153,16 @@ export class SubmitterService {
             submitterConfig.maxEvaluationDuration ?? MAX_EVALUATION_DURATION_DEFAULT;
         const unrewardedDeliveryGas = 
             submitterConfig.unrewardedDeliveryGas ?? UNREWARDED_DELIVERY_GAS_DEFAULT;
+        const verificationDeliveryGas = 
+            submitterConfig.verificationDeliveryGas ?? VERIFICATION_DELIVERY_GAS_DEFAULT;
         const minDeliveryReward =
             submitterConfig.minDeliveryReward ?? MIN_DELIVERY_REWARD_DEFAULT;
         const relativeMinDeliveryReward =
             submitterConfig.relativeMinDeliveryReward ?? RELATIVE_MIN_DELIVERY_REWARD_DEFAULT;
         const unrewardedAckGas = 
             submitterConfig.unrewardedAckGas ?? UNREWARDED_ACK_GAS_DEFAULT;
+        const verificationAckGas = 
+            submitterConfig.verificationAckGas ?? VERIFICATION_ACK_GAS_DEFAULT;
         const minAckReward =
             submitterConfig.minAckReward ?? MIN_ACK_REWARD_DEFAULT;
         const relativeMinAckReward =
@@ -173,9 +183,11 @@ export class SubmitterService {
             evaluationRetryInterval,
             maxEvaluationDuration,
             unrewardedDeliveryGas,
+            verificationDeliveryGas,
             minDeliveryReward,
             relativeMinDeliveryReward,
             unrewardedAckGas,
+            verificationAckGas,
             minAckReward,
             relativeMinAckReward,
             profitabilityFactor,
@@ -230,6 +242,10 @@ export class SubmitterService {
             unrewardedDeliveryGas:
                 chainConfig.submitter.unrewardedDeliveryGas ??
                 globalConfig.unrewardedDeliveryGas,
+
+            verificationDeliveryGas:
+                chainConfig.submitter.verificationDeliveryGas ??
+                globalConfig.verificationDeliveryGas,
 
             maxEvaluationDuration:
                 chainConfig.submitter.maxEvaluationDuration ??
@@ -246,6 +262,10 @@ export class SubmitterService {
             unrewardedAckGas:
                 chainConfig.submitter.unrewardedAckGas ??
                 globalConfig.unrewardedAckGas,
+
+            verificationAckGas:
+                chainConfig.submitter.verificationAckGas ??
+                globalConfig.verificationAckGas,
 
             minAckReward:
                 chainConfig.submitter.minAckReward ??

src/submitter/submitter.types.ts

@@ -36,9 +36,11 @@ export interface BountyEvaluationConfig {
     evaluationRetryInterval: number,
     maxEvaluationDuration: number,
     unrewardedDeliveryGas: bigint;
+    verificationDeliveryGas: bigint;
     minDeliveryReward: number;
     relativeMinDeliveryReward: number,
     unrewardedAckGas: bigint;
+    verificationAckGas: bigint;
     minAckReward: number;
     relativeMinAckReward: number;
     profitabilityFactor: number;

src/submitter/submitter.worker.ts

@@ -68,9 +68,11 @@ class SubmitterWorker {
                     evaluationRetryInterval: this.config.evaluationRetryInterval,
                     maxEvaluationDuration: this.config.maxEvaluationDuration,
                     unrewardedDeliveryGas: this.config.unrewardedDeliveryGas,
+                    verificationDeliveryGas: this.config.verificationDeliveryGas,
                     minDeliveryReward: this.config.minDeliveryReward,
                     relativeMinDeliveryReward: this.config.relativeMinDeliveryReward,
                     unrewardedAckGas: this.config.unrewardedAckGas,
+                    verificationAckGas: this.config.verificationAckGas,
                     minAckReward: this.config.minAckReward,
                     relativeMinAckReward: this.config.relativeMinAckReward,
                     profitabilityFactor: this.config.profitabilityFactor,