Fix wallet RPC race by waiting for callbacks in sendrawtransaction

src/rpc/rawtransaction.cpp

@@ -9,6 +9,7 @@
 #include "core_io.h"
 #include "init.h"
 #include "keystore.h"
+#include "validationinterface.h"
 #include "net.h"
 #include "policy/policy.h"
 #include "primitives/transaction.h"
@@ -25,6 +26,7 @@
 #include "wallet/wallet.h"
 #endif
 
+#include <future>
 #include <stdint.h>
 
 #include <univalue.h>
@@ -903,6 +905,8 @@ UniValue sendrawtransaction(const JSONRPCRequest& request)
             "\nSend the transaction (signed hex)\n" + HelpExampleCli("sendrawtransaction", "\"signedhex\"") +
             "\nAs a json rpc call\n" + HelpExampleRpc("sendrawtransaction", "\"signedhex\""));
 
+    std::promise<void> promise;
+
     RPCTypeCheck(request.params, {UniValue::VSTR, UniValue::VBOOL});
 
     // parse hex string from parameter
@@ -915,7 +919,8 @@ UniValue sendrawtransaction(const JSONRPCRequest& request)
     if (request.params.size() > 1)
         fOverrideFees = request.params[1].get_bool();
 
-    AssertLockNotHeld(cs_main);
+    { // cs_main scope
+    LOCK(cs_main);
     CCoinsViewCache& view = *pcoinsTip;
     bool fHaveChain = false;
     for (size_t o = 0; !fHaveChain && o < mtx.vout.size(); o++) {
@@ -927,7 +932,6 @@ UniValue sendrawtransaction(const JSONRPCRequest& request)
         CValidationState state;
         bool fMissingInputs;
         {
-            LOCK(cs_main);
             if (!AcceptToMemoryPool(mempool, state, MakeTransactionRef(std::move(mtx)), true, &fMissingInputs, false, !fOverrideFees)) {
                 if (state.IsInvalid()) {
                     throw JSONRPCError(RPC_TRANSACTION_REJECTED, strprintf("%i: %s", state.GetRejectCode(), state.GetRejectReason()));
@@ -937,11 +941,25 @@ UniValue sendrawtransaction(const JSONRPCRequest& request)
                     }
                     throw JSONRPCError(RPC_TRANSACTION_ERROR, state.GetRejectReason());
                 }
+            } else {
+                // If wallet is enabled, ensure that the wallet has been made aware
+                // of the new transaction prior to returning. This prevents a race
+                // where a user might call sendrawtransaction with a transaction
+                // to/from their wallet, immediately call some wallet RPC, and get
+                // a stale result because callbacks have not yet been processed.
+                CallFunctionInValidationInterfaceQueue([&promise] {
+                    promise.set_value();
+                });
             }
         }
     } else if (fHaveChain) {
         throw JSONRPCError(RPC_TRANSACTION_ALREADY_IN_CHAIN, "transaction already in block chain");
     }
+
+    } // cs_main
+
+    promise.get_future().wait();
+
     if(!g_connman)
         throw JSONRPCError(RPC_CLIENT_P2P_DISABLED, "Error: Peer-to-peer functionality missing or disabled");
 
@@ -950,6 +968,7 @@ UniValue sendrawtransaction(const JSONRPCRequest& request)
     {
         pnode->PushInventory(inv);
     });
+
     return hashTx.GetHex();
 }