Merge bitcoin/bitcoin#24649: wallet: do not count wallet utxos as external

7832e9438f5c66b88f60676d14e1e11d669eb109 test: fundrawtransaction preset input weight calculation (S3RK)
c3981e379fa088aa7aa03b2f505342a5b3bc3436 wallet: do not count wallet utxos as external (S3RK)

Pull request description:

  Correctly differentiating between external vs non-external utxos in coin control produces more accurate weight and fee estimations.

  Weight for external utxos is estimated based on the maximum signature size, while for the wallet utxos we expect minimal signature due to signature grinding.

ACKs for top commit:
  achow101:
    re-ACK 7832e9438f5c66b88f60676d14e1e11d669eb109
  Xekyo:
    re-ACK 7832e9438f5c66b88f60676d14e1e11d669eb109
  furszy:
    ACK 7832e943

Tree-SHA512: bb5635b0bd85fa9a76922a53ad3fa062286424c06a695a0e87407c665713e80a33555b644fbb13bcc1ab503dcd7f53aacbdc368d69ac0ecff8005603623ac94f

2 files changed, 18 insertions, 17 deletions

diff --git a/src/wallet/rpc/spend.cpp b/src/wallet/rpc/spend.cpp
index d1a0ba50f6..2520cd2532 100644
--- a/src/wallet/rpc/spend.cpp
+++ b/src/wallet/rpc/spend.cpp
@@ -699,19 +699,6 @@ void FundTransaction(CWallet& wallet, CMutableTransaction& tx, CAmount& fee_out,
         setSubtractFeeFromOutputs.insert(pos);
     }
 
-    // Fetch specified UTXOs from the UTXO set to get the scriptPubKeys and values of the outputs being selected
-    // and to match with the given solving_data. Only used for non-wallet outputs.
-    std::map<COutPoint, Coin> coins;
-    for (const CTxIn& txin : tx.vin) {
-        coins[txin.prevout]; // Create empty map entry keyed by prevout.
-    }
-    wallet.chain().findCoins(coins);
-    for (const auto& coin : coins) {
-        if (!coin.second.out.IsNull()) {
-            coinControl.SelectExternal(coin.first, coin.second.out);
-        }
-    }
-
     bilingual_str error;
 
     if (!FundTransaction(wallet, tx, fee_out, change_position, error, lockUnspents, setSubtractFeeFromOutputs, coinControl)) {
diff --git a/src/wallet/spend.cpp b/src/wallet/spend.cpp
index 6f79ae4e9b..ce99aeefe5 100644
--- a/src/wallet/spend.cpp
+++ b/src/wallet/spend.cpp
@@ -1023,14 +1023,28 @@ bool FundTransaction(CWallet& wallet, CMutableTransaction& tx, CAmount& nFeeRet,
 
     coinControl.fAllowOtherInputs = true;
 
-    for (const CTxIn& txin : tx.vin) {
-        coinControl.Select(txin.prevout);
-    }
-
     // Acquire the locks to prevent races to the new locked unspents between the
     // CreateTransaction call and LockCoin calls (when lockUnspents is true).
     LOCK(wallet.cs_wallet);
 
+    // Fetch specified UTXOs from the UTXO set to get the scriptPubKeys and values of the outputs being selected
+    // and to match with the given solving_data. Only used for non-wallet outputs.
+    std::map<COutPoint, Coin> coins;
+    for (const CTxIn& txin : tx.vin) {
+        coins[txin.prevout]; // Create empty map entry keyed by prevout.
+    }
+    wallet.chain().findCoins(coins);
+
+    for (const CTxIn& txin : tx.vin) {
+        // if it's not in the wallet and corresponding UTXO is found than select as external output
+        const auto& outPoint = txin.prevout;
+        if (wallet.mapWallet.find(outPoint.hash) == wallet.mapWallet.end() && !coins[outPoint].out.IsNull()) {
+            coinControl.SelectExternal(outPoint, coins[outPoint].out);
+        } else {
+            coinControl.Select(outPoint);
+        }
+    }
+
     FeeCalculation fee_calc_out;
     std::optional<CreatedTransactionResult> txr = CreateTransaction(wallet, vecSend, nChangePosInOut, error, coinControl, fee_calc_out, false);
     if (!txr) return false;