wallet: Remove path checking code from loadwallet RPC

Summary:
This commit does not change behavior except for error messages which now
include more complete information.

This is a backport of [[bitcoin/bitcoin#19619 | core#19619]] [6/8]
bitcoin/bitcoin@a987438

Depends on D10228
Depends on D10213 (for rpc_createmultisig.py)

Test Plan: `ninja all check-all`

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D10229

src/wallet/rpcwallet.cpp

@@ -3128,24 +3128,10 @@ static UniValue loadwallet(const Config &config,
 
     WalletContext &context = EnsureWalletContext(request.context);
     const std::string name(request.params[0].get_str());
-    fs::path path(fs::absolute(name, GetWalletDir()));
-
-    if (fs::symlink_status(path).type() == fs::file_not_found) {
-        throw JSONRPCError(RPC_WALLET_NOT_FOUND,
-                           "Wallet " + name + " not found.");
-    } else if (fs::is_directory(path)) {
-        // The given filename is a directory. Check that there's a wallet.dat
-        // file.
-        fs::path wallet_dat_file = path / "wallet.dat";
-        if (fs::symlink_status(wallet_dat_file).type() == fs::file_not_found) {
-            throw JSONRPCError(RPC_WALLET_NOT_FOUND,
-                               "Directory " + name +
-                                   " does not contain a wallet.dat file.");
-        }
-    }
 
     DatabaseOptions options;
     DatabaseStatus status;
+    options.require_existing = true;
     bilingual_str error;
     std::vector<bilingual_str> warnings;
     std::optional<bool> load_on_start =
@@ -3155,7 +3141,13 @@ static UniValue loadwallet(const Config &config,
     std::shared_ptr<CWallet> const wallet = LoadWallet(
         *context.chain, name, load_on_start, options, status, error, warnings);
     if (!wallet) {
-        throw JSONRPCError(RPC_WALLET_ERROR, error.original);
+        // Map bad format to not found, since bad format is returned when the
+        // wallet directory exists, but doesn't contain a data file.
+        RPCErrorCode code = status == DatabaseStatus::FAILED_NOT_FOUND ||
+                                    status == DatabaseStatus::FAILED_BAD_FORMAT
+                                ? RPC_WALLET_NOT_FOUND
+                                : RPC_WALLET_ERROR;
+        throw JSONRPCError(code, error.original);
     }
 
     UniValue obj(UniValue::VOBJ);

test/functional/rpc_createmultisig.py

@@ -133,8 +133,12 @@ def do_multisig(self):
             try:
                 node1.loadwallet('wmulti')
             except JSONRPCException as e:
-                if e.error['code'] == -18 and \
-                        'Wallet wmulti not found' in e.error['message']:
+                path = os.path.join(self.options.tmpdir, "node1", "regtest",
+                                    "wallets", "wmulti")
+                if e.error['code'] == -18 and (
+                        "Wallet file verification failed. Failed to load "
+                        "database path '{}'. Path does not exist.".format(path)
+                        in e.error['message']):
                     node1.createwallet(wallet_name='wmulti',
                                        disable_private_keys=True)
                 else:

test/functional/wallet_multiwallet.py

@@ -278,8 +278,13 @@ def wallet_file(name):
         assert_equal(set(self.nodes[0].listwallets()), set(wallet_names))
 
         # Fail to load if wallet doesn't exist
-        assert_raises_rpc_error(-18, 'Wallet wallets not found.',
-                                self.nodes[0].loadwallet, 'wallets')
+        path = os.path.join(self.options.tmpdir, "node0", "regtest",
+                            "wallets", "wallets")
+        assert_raises_rpc_error(
+            -18,
+            "Wallet file verification failed. Failed to load database path "
+            "'{}'. Path does not exist.".format(path),
+            self.nodes[0].loadwallet, 'wallets')
 
         # Fail to load duplicate wallets
         path = os.path.join(
@@ -332,8 +337,13 @@ def wallet_file(name):
         # Fail to load if a directory is specified that doesn't contain a
         # wallet
         os.mkdir(wallet_dir('empty_wallet_dir'))
-        assert_raises_rpc_error(-18, "Directory empty_wallet_dir does not contain a wallet.dat file",
-                                self.nodes[0].loadwallet, 'empty_wallet_dir')
+        path = os.path.join(self.options.tmpdir, "node0", "regtest",
+                            "wallets", "empty_wallet_dir")
+        assert_raises_rpc_error(
+            -18,
+            "Wallet file verification failed. Failed to load database "
+            "path '{}'. Data is not in recognized format.".format(path),
+            self.nodes[0].loadwallet, 'empty_wallet_dir')
 
         self.log.info("Test dynamic wallet creation.")