qt: Fix regression in TransactionTableModel

Since #17993 a crash is possible on exit.

Co-authored-by: Russell Yanofsky <russ@yanofsky.org>

1 files changed, 6 insertions, 1 deletions

diff --git a/src/qt/walletmodel.cpp b/src/qt/walletmodel.cpp
index 671b5e1ce6..fde7bb29c1 100644
--- a/src/qt/walletmodel.cpp
+++ b/src/qt/walletmodel.cpp
@@ -87,7 +87,7 @@ void WalletModel::pollBalanceChanged()
 {
     // Avoid recomputing wallet balances unless a TransactionChanged or
     // BlockTip notification was received.
-    if (!fForceCheckBalanceChanged && m_cached_last_update_tip == m_client_model->getBestBlockHash()) return;
+    if (!fForceCheckBalanceChanged && m_cached_last_update_tip == getLastBlockProcessed()) return;
 
     // Try to get balances and return early if locks can't be acquired. This
     // avoids the GUI from getting stuck on periodical polls if the core is
@@ -588,3 +588,8 @@ void WalletModel::refresh(bool pk_hash_only)
 {
     addressTableModel = new AddressTableModel(this, pk_hash_only);
 }
+
+uint256 WalletModel::getLastBlockProcessed() const
+{
+    return m_client_model ? m_client_model->getBestBlockHash() : uint256{};
+}