wallet: SelectExternal actually external inputs

If an external input's utxo was created by a transaction that the wallet
knows about, then it would not be selected using SelectExternal. This
results in either funding failure or incorrect weight calculation.

1 files changed, 8 insertions, 4 deletions

diff --git a/src/wallet/spend.cpp b/src/wallet/spend.cpp
index d6362c1f14..bffb665fa8 100644
--- a/src/wallet/spend.cpp
+++ b/src/wallet/spend.cpp
@@ -1127,12 +1127,16 @@ bool FundTransaction(CWallet& wallet, CMutableTransaction& tx, CAmount& nFeeRet,
     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 {
+        if (wallet.IsMine(outPoint)) {
+            // The input was found in the wallet, so select as internal
             coinControl.Select(outPoint);
+        } else if (coins[outPoint].out.IsNull()) {
+            error = _("Unable to find UTXO for external input");
+            return false;
+        } else {
+            // The input was not in the wallet, but is in the UTXO set, so select as external
+            coinControl.SelectExternal(outPoint, coins[outPoint].out);
         }
     }