wallet, rpc: Give warning in listwalletdir for legacy wallets

src/wallet/rpc/wallet.cpp

@@ -135,6 +135,10 @@ static RPCHelpMan listwalletdir()
                             {RPCResult::Type::OBJ, "", "",
                             {
                                 {RPCResult::Type::STR, "name", "The wallet name"},
+                                {RPCResult::Type::ARR, "warnings", /*optional=*/true, "Warning messages, if any, related to loading the wallet.",
+                                {
+                                    {RPCResult::Type::STR, "", ""},
+                                }},
                             }},
                         }},
                     }
@@ -146,9 +150,14 @@ static RPCHelpMan listwalletdir()
         [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
 {
     UniValue wallets(UniValue::VARR);
-    for (const auto& [path, _] : ListDatabases(GetWalletDir())) {
+    for (const auto& [path, db_type] : ListDatabases(GetWalletDir())) {
         UniValue wallet(UniValue::VOBJ);
         wallet.pushKV("name", path.utf8string());
+                UniValue warnings(UniValue::VARR);
+        if (db_type == "bdb") {
+            warnings.push_back("This wallet is a legacy wallet and will need to be migrated with migratewallet before it can be loaded");
+        }
+        wallet.pushKV("warnings", warnings);
         wallets.push_back(std::move(wallet));
     }
 

test/functional/wallet_migration.py

@@ -113,6 +113,11 @@ class WalletMigrationTest(BitcoinTestFramework):
             shutil.copyfile(self.old_node.wallets_path / "wallet.dat", self.master_node.wallets_path / "wallet.dat")
         else:
             shutil.copytree(self.old_node.wallets_path / wallet_name, self.master_node.wallets_path / wallet_name)
+        # Check that the wallet shows up in listwalletdir with a warning about migration
+        wallets = self.master_node.listwalletdir()
+        for w in wallets["wallets"]:
+            if w["name"] == wallet_name:
+                assert_equal(w["warnings"], ["This wallet is a legacy wallet and will need to be migrated with migratewallet before it can be loaded"])
         # Migrate, checking that rescan does not occur
         with self.master_node.assert_debug_log(expected_msgs=[], unexpected_msgs=["Rescanning"]):
             migrate_info = self.master_node.migratewallet(wallet_name=wallet_name, **kwargs)
@@ -548,7 +553,7 @@ class WalletMigrationTest(BitcoinTestFramework):
         assert_equal(info["format"], "sqlite")
 
         walletdir_list = wallet.listwalletdir()
-        assert {"name": info["walletname"]} in walletdir_list["wallets"]
+        assert {"name": info["walletname"]} in [{"name": w["name"]} for w in walletdir_list["wallets"]]
 
         # Check backup existence and its non-empty wallet filename
         backup_filename = f"default_wallet_{curr_time}.legacy.bak"

test/functional/wallet_multiwallet.py

@@ -72,7 +72,7 @@ class MultiWalletTest(BitcoinTestFramework):
                 return wallet_dir(name, "wallet.dat")
             return wallet_dir(name)
 
-        assert_equal(self.nodes[0].listwalletdir(), {'wallets': [{'name': self.default_wallet_name}]})
+        assert_equal(self.nodes[0].listwalletdir(), {'wallets': [{'name': self.default_wallet_name, "warnings": []}]})
 
         # check wallet.dat is created
         self.stop_nodes()