Merge pull request #5232 from BitGo/COIN-2432

fix: use max spendable amount to sweep balance

Author: hrishikeshjain

modules/bitgo/test/v2/unit/wallet.ts

@@ -1790,6 +1790,41 @@ describe('V2 Wallet:', function () {
     });
   });
 
+  describe('sweep wallet', function () {
+    let basecoin;
+    let wallet;
+
+    before(async function () {
+      basecoin = bitgo.coin('ttrx');
+      const walletData = {
+        id: '5b34252f1bf349930e34020a',
+        coin: 'ttrx',
+        keys: ['5b3424f91bf349930e340175'],
+      };
+      wallet = new Wallet(bitgo, basecoin, walletData);
+    });
+
+    it('should use maximum spendable balance of wallet to sweep funds ', async function () {
+      const path = `/api/v2/${wallet.coin()}/wallet/${wallet.id()}/maximumSpendable`;
+      const response = nock(bgUrl).get(path).reply(200, {
+        coin: 'ttrx',
+        maximumSpendable: 65000,
+      });
+      const body = {
+        coin: 'ttrx',
+        address: '2MwvR24yqym2CgHMp7zwvdeqBa4F8KTqunS',
+      };
+      try {
+        await wallet.sweep(body);
+      } catch (e) {
+        // the sweep method will probably throw an exception for not having all of the correct nocks
+        // we only care about maximum spendable balance being used to sweep funds
+      }
+
+      response.isDone().should.be.true();
+    });
+  });
+
   describe('Transaction prebuilds', function () {
     let ethWallet;
 

modules/sdk-core/src/bitgo/wallet/wallet.ts

@@ -937,19 +937,23 @@ export class Wallet implements IWallet {
           'cannot sweep when unconfirmed funds exist on the wallet, please wait until all inbound transactions confirm'
         );
       }
-
-      const value = this.spendableBalanceString();
-      if (_.isUndefined(value) || value === '0') {
+      const value = await this.bitgo.get(this.url('/maximumSpendable')).result();
+      const maximumSpendable = new BigNumber(value.maximumSpendable);
+      if (value !== undefined || maximumSpendable.isZero()) {
         throw new Error('no funds to sweep');
       }
-      (params as any).recipients = [
-        {
-          address: params.address,
-          amount: value,
-        },
-      ];
 
-      return this.sendMany(params);
+      const sendManyParams: SendManyOptions = {
+        ...params,
+        recipients: [
+          {
+            address: params.address || '', // Ensure address is always a string
+            amount: maximumSpendable.toString(),
+          },
+        ],
+      };
+
+      return this.sendMany(sendManyParams);
     }
     // the following flow works for all UTXO coins