[wallet] correctly limit output group size

src/wallet/wallet.cpp

@@ -4423,7 +4423,10 @@ std::vector<OutputGroup> CWallet::GroupOutputs(const std::vector<COutput>& outpu
             size_t ancestors, descendants;
             mempool.GetTransactionAncestry(output.tx->GetHash(), ancestors, descendants);
             if (!single_coin && ExtractDestination(output.tx->tx->vout[output.i].scriptPubKey, dst)) {
-                if (gmap.count(dst) == 10) {
+                // Limit output groups to no more than 10 entries, to protect
+                // against inadvertently creating a too-large transaction
+                // when using -avoidpartialspends
+                if (gmap[dst].m_outputs.size() >= 10) {
                     groups.push_back(gmap[dst]);
                     gmap.erase(dst);
                 }