allow low fees for unlock txes, add test

Author: UdjinM6

src/validation.cpp

@@ -981,6 +981,8 @@ static bool AcceptToMemoryPoolWithTime(const CChainParams& chainparams, CTxMemPo
                         const CAmount nAbsurdFee, bool test_accept) EXCLUSIVE_LOCKS_REQUIRED(cs_main)
 {
     std::vector<COutPoint> coins_to_uncache;
+    // Let Asset Unlock tx into mempool ignoring all the limits
+    bypass_limits = bypass_limits || (tx->nVersion == 3 && tx->nType == TRANSACTION_ASSET_UNLOCK);
     MemPoolAccept::ATMPArgs args { chainparams, state, nAcceptTime, bypass_limits, nAbsurdFee, coins_to_uncache, test_accept };
 
     assert(std::addressof(::ChainstateActive()) == std::addressof(active_chainstate));

test/functional/feature_asset_locks.py

@@ -300,11 +300,13 @@ def run_test(self):
         asset_unlock_tx_too_late = self.create_assetunlock(103, COIN, pubkey)
         asset_unlock_tx_too_big_fee = self.create_assetunlock(104, COIN, pubkey, fee=int(Decimal("0.1") * COIN))
         asset_unlock_tx_zero_fee = self.create_assetunlock(105, COIN, pubkey, fee=0)
+        asset_unlock_tx_low_fee = self.create_assetunlock(106, COIN, pubkey, fee=1)
         asset_unlock_tx_duplicate_index = copy.deepcopy(asset_unlock_tx)
         asset_unlock_tx_duplicate_index.vout[0].nValue += COIN
         too_late_height = node.getblock(node.getbestblockhash())["height"] + 48
 
         self.check_mempool_result(tx=asset_unlock_tx, result_expected={'allowed': True})
+        self.check_mempool_result(tx=asset_unlock_tx_low_fee, result_expected={'allowed': True})
         self.check_mempool_result(tx=asset_unlock_tx_too_big_fee,
                 result_expected={'allowed': False, 'reject-reason' : 'absurdly-high-fee'})
         self.check_mempool_result(tx=asset_unlock_tx_zero_fee,