wallet: unload, notify GUI as soon as possible

Releases wallet shared pointers prior to doing the
final settings update and prevent GUI races trying
to access a wallet that is no longer loaded.

Author: furszy

src/wallet/wallet.cpp

@@ -162,10 +162,14 @@ bool RemoveWallet(WalletContext& context, const std::shared_ptr<CWallet>& wallet
 
     // Unregister with the validation interface which also drops shared pointers.
     wallet->m_chain_notifications_handler.reset();
-    LOCK(context.wallets_mutex);
-    std::vector<std::shared_ptr<CWallet>>::iterator i = std::find(context.wallets.begin(), context.wallets.end(), wallet);
-    if (i == context.wallets.end()) return false;
-    context.wallets.erase(i);
+    {
+        LOCK(context.wallets_mutex);
+        std::vector<std::shared_ptr<CWallet>>::iterator i = std::find(context.wallets.begin(), context.wallets.end(), wallet);
+        if (i == context.wallets.end()) return false;
+        context.wallets.erase(i);
+    }
+    // Notify unload so that upper layers release the shared pointer.
+    wallet->NotifyUnload();
 
     // Write the wallet setting
     UpdateWalletSetting(chain, name, load_on_start, warnings);
@@ -249,10 +253,6 @@ void UnloadWallet(std::shared_ptr<CWallet>&& wallet)
         auto it = g_unloading_wallet_set.insert(name);
         assert(it.second);
     }
-    // The wallet can be in use so it's not possible to explicitly unload here.
-    // Notify the unload intent so that all remaining shared pointers are
-    // released.
-    wallet->NotifyUnload();
 
     // Time to ditch our shared_ptr and wait for ReleaseWallet call.
     wallet.reset();