wallet2: enable ignoring fractional outputs also when sweeping

src/wallet/wallet2.cpp

@@ -9786,6 +9786,17 @@ std::vector<wallet2::pending_tx> wallet2::create_transactions_all(uint64_t below
   std::vector<size_t> unused_dust_indices;
   const bool use_rct = use_fork_rules(4, 0);
 
+  // determine threshold for fractional amount
+  const bool use_per_byte_fee = use_fork_rules(HF_VERSION_PER_BYTE_FEE, 0);
+  const bool bulletproof = use_fork_rules(get_bulletproof_fork(), 0);
+  const uint64_t base_fee  = get_base_fee();
+  const uint64_t fee_multiplier = get_fee_multiplier(priority, get_fee_algorithm());
+  const size_t tx_weight_one_ring = estimate_tx_weight(use_rct, 1, fake_outs_count, 2, 0, bulletproof);
+  const size_t tx_weight_two_rings = estimate_tx_weight(use_rct, 2, fake_outs_count, 2, 0, bulletproof);
+  THROW_WALLET_EXCEPTION_IF(tx_weight_one_ring > tx_weight_two_rings, error::wallet_internal_error, "Estimated tx weight with 1 input is larger than with 2 inputs!");
+  const size_t tx_weight_per_ring = tx_weight_two_rings - tx_weight_one_ring;
+  const uint64_t fractional_threshold = (fee_multiplier * base_fee * tx_weight_per_ring) / (use_per_byte_fee ? 1 : 1024);
+
   THROW_WALLET_EXCEPTION_IF(unlocked_balance(subaddr_account, false) == 0, error::wallet_internal_error, "No unlocked balance in the entire wallet");
 
   std::map<uint32_t, std::pair<std::vector<size_t>, std::vector<size_t>>> unused_transfer_dust_indices_per_subaddr;
@@ -9795,6 +9806,11 @@ std::vector<wallet2::pending_tx> wallet2::create_transactions_all(uint64_t below
   for (size_t i = 0; i < m_transfers.size(); ++i)
   {
     const transfer_details& td = m_transfers[i];
+    if (m_ignore_fractional_outputs && td.amount() < fractional_threshold)
+    {
+      MDEBUG("Ignoring output " << i << " of amount " << print_money(td.amount()) << " which is below threshold " << print_money(fractional_threshold));
+      continue;
+    }
     if (!is_spent(td, false) && !td.m_frozen && !td.m_key_image_partial && (use_rct ? true : !td.is_rct()) && is_transfer_unlocked(td) && td.m_subaddr_index.major == subaddr_account && (subaddr_indices.empty() || subaddr_indices.count(td.m_subaddr_index.minor) == 1))
     {
       fund_found = true;