Merge bitcoin#24678: Prevent wallet unload on GetWalletForJSONRPCRequest

f59959e wallet: Prevent wallet unload on GetWalletForJSONRPCRequest (João Barbosa)

Pull request description:

  Don't extend shared ownership of all wallets to `GetWalletForJSONRPCRequest` scope.

ACKs for top commit:
  achow101:
    ACK f59959e
  shaavan:
    Code Review ACK f59959e
  theStack:
    Concept and code-review ACK f59959e

Tree-SHA512: 7c0294098b5c32acaab8cc6fcf17a581d580ad1a557ba0602a9506074ac035815739afb4a25b3e61be9132535c7fc3ec7ef5137c1dfc9d4078f13663d508ef55

Author: fanquake

src/wallet/rpc/util.cpp

@@ -64,12 +64,11 @@ std::shared_ptr<CWallet> GetWalletForJSONRPCRequest(const JSONRPCRequest& reques
         return pwallet;
     }
 
-    std::vector<std::shared_ptr<CWallet>> wallets = GetWallets(context);
-    if (wallets.size() == 1) {
-        return wallets[0];
-    }
+    size_t count{0};
+    auto wallet = GetDefaultWallet(context, count);
+    if (wallet) return wallet;
 
-    if (wallets.empty()) {
+    if (count == 0) {
         throw JSONRPCError(
             RPC_WALLET_NOT_FOUND, "No wallet is loaded. Load a wallet using loadwallet or create a new one with createwallet. (Note: A default wallet is no longer automatically created)");
     }

src/wallet/wallet.cpp

@@ -149,6 +149,13 @@ std::vector<std::shared_ptr<CWallet>> GetWallets(WalletContext& context)
     return context.wallets;
 }
 
+std::shared_ptr<CWallet> GetDefaultWallet(WalletContext& context, size_t& count)
+{
+    LOCK(context.wallets_mutex);
+    count = context.wallets.size();
+    return count == 1 ? context.wallets[0] : nullptr;
+}
+
 std::shared_ptr<CWallet> GetWallet(WalletContext& context, const std::string& name)
 {
     LOCK(context.wallets_mutex);

src/wallet/wallet.h

@@ -64,6 +64,7 @@ bool AddWallet(WalletContext& context, const std::shared_ptr<CWallet>& wallet);
 bool RemoveWallet(WalletContext& context, const std::shared_ptr<CWallet>& wallet, std::optional<bool> load_on_start, std::vector<bilingual_str>& warnings);
 bool RemoveWallet(WalletContext& context, const std::shared_ptr<CWallet>& wallet, std::optional<bool> load_on_start);
 std::vector<std::shared_ptr<CWallet>> GetWallets(WalletContext& context);
+std::shared_ptr<CWallet> GetDefaultWallet(WalletContext& context, size_t& count);
 std::shared_ptr<CWallet> GetWallet(WalletContext& context, const std::string& name);
 std::shared_ptr<CWallet> LoadWallet(WalletContext& context, const std::string& name, std::optional<bool> load_on_start, const DatabaseOptions& options, DatabaseStatus& status, bilingual_str& error, std::vector<bilingual_str>& warnings);
 std::shared_ptr<CWallet> CreateWallet(WalletContext& context, const std::string& name, std::optional<bool> load_on_start, DatabaseOptions& options, DatabaseStatus& status, bilingual_str& error, std::vector<bilingual_str>& warnings);