Add RPC call abandontransaction

- Make wallet descendant searching more efficient
- Add new rpc call: abandontransaction

Unconfirmed transactions that are not in your mempool either due to eviction or other means may be unlikely to be mined.  abandontransaction gives the wallet a way to no longer consider as spent the coins that are inputs to such a transaction.  All dependent transactions in the wallet will also be marked as abandoned.

- Add RPC test for abandoned and conflicted transactions.
- [Wallet] Call notification signal when a transaction is abandoned

Github-Pull: #7312
Rebased-From: 9e69717254 01e06d1fa3 df0e2226d9 d11fc1695c

src/wallet/rpcwallet.cpp

@@ -1764,6 +1764,40 @@ UniValue gettransaction(const UniValue& params, bool fHelp)
     return entry;
 }
 
+UniValue abandontransaction(const UniValue& params, bool fHelp)
+{
+    if (!EnsureWalletIsAvailable(fHelp))
+        return NullUniValue;
+
+    if (fHelp || params.size() != 1)
+        throw runtime_error(
+            "abandontransaction \"txid\"\n"
+            "\nMark in-wallet transaction <txid> as abandoned\n"
+            "This will mark this transaction and all its in-wallet descendants as abandoned which will allow\n"
+            "for their inputs to be respent.  It can be used to replace \"stuck\" or evicted transactions.\n"
+            "It only works on transactions which are not included in a block and are not currently in the mempool.\n"
+            "It has no effect on transactions which are already conflicted or abandoned.\n"
+            "\nArguments:\n"
+            "1. \"txid\"    (string, required) The transaction id\n"
+            "\nResult:\n"
+            "\nExamples:\n"
+            + HelpExampleCli("abandontransaction", "\"1075db55d416d3ca199f55b6084e2115b9345e16c5cf302fc80e9d5fbf5d48d\"")
+            + HelpExampleRpc("abandontransaction", "\"1075db55d416d3ca199f55b6084e2115b9345e16c5cf302fc80e9d5fbf5d48d\"")
+        );
+
+    LOCK2(cs_main, pwalletMain->cs_wallet);
+
+    uint256 hash;
+    hash.SetHex(params[0].get_str());
+
+    if (!pwalletMain->mapWallet.count(hash))
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid or non-wallet transaction id");
+    if (!pwalletMain->AbandonTransaction(hash))
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Transaction not eligible for abandonment");
+
+    return NullUniValue;
+}
+
 
 UniValue backupwallet(const UniValue& params, bool fHelp)
 {