fix: ensure getTransactionCost not returns fee values as 0 when nod…

…e `minGasPrice` is 0 (#1523)

.changeset/six-shoes-impress.md

@@ -0,0 +1,7 @@
+---
+"@fuel-ts/math": minor
+"@fuel-ts/providers": minor
+"@fuel-ts/wallet": minor
+---
+
+ensure estimated fee values returned by getTransactionCost are never 0

packages/math/src/bn.test.ts

@@ -477,6 +477,12 @@ describe('Math - BN', () => {
     }).toThrow("Decimal can't have more than 5 digits.");
   });
 
+  it('should normalize zero to one', () => {
+    expect(bn(0).normalizeZeroToOne().eq(1)).toBeTruthy();
+
+    expect(bn(2).normalizeZeroToOne().eq(1)).not.toBeTruthy();
+  });
+
   it('should match valueOf to toString with no base arguments', () => {
     expect(bn('1000000000').valueOf()).toEqual('1000000000');
     expect(bn('2').valueOf()).toEqual('2');

packages/math/src/bn.ts

@@ -264,6 +264,10 @@ export class BN extends BnJs implements BNInputOverrides, BNHiddenTypes, BNHelpe
   maxU64(): BN {
     return this.gte(this.MAX_U64) ? new BN(this.MAX_U64) : this;
   }
+
+  normalizeZeroToOne(): BN {
+    return this.isZero() ? new BN(1) : this;
+  }
   // END ANCHOR: OVERRIDES to avoid losing references
 }
 

packages/providers/src/coin-quantity.ts

@@ -38,7 +38,9 @@ export interface IAddAmountToAssetParams {
 }
 
 export const addAmountToAsset = (params: IAddAmountToAssetParams): CoinQuantity[] => {
-  const { amount, assetId, coinQuantities } = params;
+  const { amount, assetId } = params;
+
+  const coinQuantities = [...params.coinQuantities];
 
   const assetIdx = coinQuantities.findIndex((coinQuantity) => coinQuantity.assetId === assetId);
 

packages/providers/src/provider.ts

@@ -771,6 +771,14 @@ export default class Provider {
       gasUsed = minGas;
     }
 
+    const usedFee = calculatePriceWithFactor(
+      gasUsed,
+      gasPrice,
+      gasPriceFactor
+    ).normalizeZeroToOne();
+    const minFee = calculatePriceWithFactor(minGas, gasPrice, gasPriceFactor).normalizeZeroToOne();
+    const maxFee = calculatePriceWithFactor(maxGas, gasPrice, gasPriceFactor).normalizeZeroToOne();
+
     return {
       requiredQuantities: allQuantities,
       receipts,
@@ -779,9 +787,9 @@ export default class Provider {
       gasPrice,
       minGas,
       maxGas,
-      usedFee: calculatePriceWithFactor(gasUsed, gasPrice, gasPriceFactor),
-      minFee: calculatePriceWithFactor(minGas, gasPrice, gasPriceFactor),
-      maxFee: calculatePriceWithFactor(maxGas, gasPrice, gasPriceFactor),
+      usedFee,
+      minFee,
+      maxFee,
     };
   }
 

packages/providers/test/provider.test.ts

@@ -994,4 +994,28 @@ describe('Provider', () => {
       witnessLimit: transactionRequest.witnessLimit,
     });
   });
+
+  it('should ensure estimated fee values on getTransactionCost are never 0', async () => {
+    const provider = await Provider.create(FUEL_NETWORK_URL);
+
+    const request = new ScriptTransactionRequest();
+
+    // forcing calculatePriceWithFactor to return 0
+    const calculatePriceWithFactorMock = jest
+      .spyOn(gasMod, 'calculatePriceWithFactor')
+      .mockReturnValue(bn(0));
+
+    const normalizeZeroToOneSpy = jest.spyOn(BN.prototype, 'normalizeZeroToOne');
+
+    const { minFee, maxFee, usedFee } = await provider.getTransactionCost(request);
+
+    expect(calculatePriceWithFactorMock).toHaveBeenCalledTimes(3);
+
+    expect(normalizeZeroToOneSpy).toHaveBeenCalledTimes(3);
+    expect(normalizeZeroToOneSpy).toHaveReturnedWith(bn(1));
+
+    expect(maxFee.eq(0)).not.toBeTruthy();
+    expect(usedFee.eq(0)).not.toBeTruthy();
+    expect(minFee.eq(0)).not.toBeTruthy();
+  });
 });

packages/wallet/src/account.ts

@@ -207,20 +207,22 @@ export class Account extends AbstractAccount {
    * Adds resources to the transaction enough to fund it.
    *
    * @param request - The transaction request.
+   * @param coinQuantities - The coin quantities required to execute the transaction.
+   * @param fee - The estimated transaction fee.
    * @returns A promise that resolves when the resources are added to the transaction.
    */
   async fund<T extends TransactionRequest>(
     request: T,
-    quantities: CoinQuantity[],
+    coinQuantities: CoinQuantity[],
     fee: BN
   ): Promise<void> {
-    // TODO: Rollback to fee value after fix fee calculation
-    addAmountToAsset({
+    const updatedQuantities = addAmountToAsset({
       amount: bn(fee),
       assetId: BaseAssetId,
-      coinQuantities: quantities,
+      coinQuantities,
     });
-    const resources = await this.getResourcesToSpend(quantities);
+
+    const resources = await this.getResourcesToSpend(updatedQuantities);
     request.addResources(resources);
   }