Merge #15652: wallet: Update transactions with current mempool after load

4bf1b1cefa qa: Check unconfirmed balance after loadwallet (João Barbosa)
2ebf650b2e wallet: Update transactions with current mempool after load (João Barbosa)
57908a739c interfaces: Add Chain::requestMempoolTransactions (João Barbosa)
0440481c6b wallet: Move CWallet::ReacceptWalletTransactions locks to callers (João Barbosa)

Pull request description:

  Fixes #15591.

ACKs for commit 4bf1b1:
  MarcoFalke:
    re-utACK 4bf1b1cefa
  jnewbery:
    utACK 4bf1b1cefa9723bf2cfa8b1a938757abc99bb17b

Tree-SHA512: 604b1057c7f9fc3772084bf6914e52dd1a68a1cfd365f907e8ec78f6f5f726bc56a3cad9f2b665642714fbf3d51e37c1184ac396460bddeafd918e8f9f7af392

2 files changed, 17 insertions, 0 deletions

diff --git a/src/interfaces/chain.cpp b/src/interfaces/chain.cpp
index 0c765f209..e409ced60 100644
--- a/src/interfaces/chain.cpp
+++ b/src/interfaces/chain.cpp
@@ -367,6 +367,13 @@ public:
     {
         return MakeUnique<RpcHandlerImpl>(command);
     }
+    void requestMempoolTransactions(Notifications& notifications) override
+    {
+        LOCK2(::cs_main, ::mempool.cs);
+        for (const CTxMemPoolEntry& entry : ::mempool.mapTx) {
+            notifications.TransactionAddedToMempool(entry.GetSharedTx());
+        }
+    }
 };
 } // namespace
 
diff --git a/src/interfaces/chain.h b/src/interfaces/chain.h
index a9b05f27f..d11a59241 100644
--- a/src/interfaces/chain.h
+++ b/src/interfaces/chain.h
@@ -269,6 +269,16 @@ public:
     //! Register handler for RPC. Command is not copied, so reference
     //! needs to remain valid until Handler is disconnected.
     virtual std::unique_ptr<Handler> handleRpc(const CRPCCommand& command) = 0;
+
+    //! Synchronously send TransactionAddedToMempool notifications about all
+    //! current mempool transactions to the specified handler and return after
+    //! the last one is sent. These notifications aren't coordinated with async
+    //! notifications sent by handleNotifications, so out of date async
+    //! notifications from handleNotifications can arrive during and after
+    //! synchronous notifications from requestMempoolTransactions. Clients need
+    //! to be prepared to handle this by ignoring notifications about unknown
+    //! removed transactions and already added new transactions.
+    virtual void requestMempoolTransactions(Notifications& notifications) = 0;
 };
 
 //! Interface to let node manage chain clients (wallets, or maybe tools for