[wallet] Support creating a blank wallet

A blank wallet is a wallet that has no keys, script or watch only things.
A new wallet flag indicating that it is blank will be set when the wallet
is blank. Once it is no longer blank (a seed has been generated, keys or
scripts imported, etc), the flag will be unset.

1 files changed, 23 insertions, 7 deletions

diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
index c96a9b0aff..674c10879f 100644
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -170,12 +170,18 @@ static UniValue getnewaddress(const JSONRPCRequest& request)
                 },
             }.ToString());
 
+    // Belt and suspenders check for disabled private keys
     if (pwallet->IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS)) {
         throw JSONRPCError(RPC_WALLET_ERROR, "Error: Private keys are disabled for this wallet");
     }
 
     LOCK(pwallet->cs_wallet);
 
+    if (!pwallet->CanGetAddresses()) {
+        throw JSONRPCError(RPC_WALLET_ERROR, "Error: This wallet has no available keys");
+    }
+
+
     // Parse the label first so we don't generate a key if there's an error
     std::string label;
     if (!request.params[0].isNull())
@@ -231,12 +237,17 @@ static UniValue getrawchangeaddress(const JSONRPCRequest& request)
                 },
             }.ToString());
 
+    // Belt and suspenders check for disabled private keys
     if (pwallet->IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS)) {
         throw JSONRPCError(RPC_WALLET_ERROR, "Error: Private keys are disabled for this wallet");
     }
 
     LOCK(pwallet->cs_wallet);
 
+    if (!pwallet->CanGetAddresses(true)) {
+        throw JSONRPCError(RPC_WALLET_ERROR, "Error: This wallet has no available keys");
+    }
+
     if (!pwallet->IsLocked()) {
         pwallet->TopUpKeyPool();
     }
@@ -2578,13 +2589,14 @@ static UniValue loadwallet(const JSONRPCRequest& request)
 
 static UniValue createwallet(const JSONRPCRequest& request)
 {
-    if (request.fHelp || request.params.size() < 1 || request.params.size() > 2) {
+    if (request.fHelp || request.params.size() < 1 || request.params.size() > 3) {
         throw std::runtime_error(
             RPCHelpMan{"createwallet",
                 "\nCreates and loads a new wallet.\n",
                 {
                     {"wallet_name", RPCArg::Type::STR, /* opt */ false, /* default_val */ "", "The name for the new wallet. If this is a path, the wallet will be created at the path location."},
                     {"disable_private_keys", RPCArg::Type::BOOL, /* opt */ true, /* default_val */ "false", "Disable the possibility of private keys (only watchonlys are possible in this mode)."},
+                    {"blank", RPCArg::Type::BOOL, /* opt */ true, /* default_val */ "false", "Create a blank wallet. A blank wallet has no keys or HD seed. One can be set using sethdseed."},
                 },
                 RPCResult{
             "{\n"
@@ -2601,9 +2613,13 @@ static UniValue createwallet(const JSONRPCRequest& request)
     std::string error;
     std::string warning;
 
-    bool disable_privatekeys = false;
-    if (!request.params[1].isNull()) {
-        disable_privatekeys = request.params[1].get_bool();
+    uint64_t flags = 0;
+    if (!request.params[1].isNull() && request.params[1].get_bool()) {
+        flags |= WALLET_FLAG_DISABLE_PRIVATE_KEYS;
+    }
+
+    if (!request.params[2].isNull() && request.params[2].get_bool()) {
+        flags |= WALLET_FLAG_BLANK_WALLET;
     }
 
     WalletLocation location(request.params[0].get_str());
@@ -2616,7 +2632,7 @@ static UniValue createwallet(const JSONRPCRequest& request)
         throw JSONRPCError(RPC_WALLET_ERROR, "Wallet file verification failed: " + error);
     }
 
-    std::shared_ptr<CWallet> const wallet = CWallet::CreateWalletFromFile(*g_rpc_interfaces->chain, location, (disable_privatekeys ? (uint64_t)WALLET_FLAG_DISABLE_PRIVATE_KEYS : 0));
+    std::shared_ptr<CWallet> const wallet = CWallet::CreateWalletFromFile(*g_rpc_interfaces->chain, location, flags);
     if (!wallet) {
         throw JSONRPCError(RPC_WALLET_ERROR, "Wallet creation failed.");
     }
@@ -3880,7 +3896,7 @@ UniValue sethdseed(const JSONRPCRequest& request)
     LOCK(pwallet->cs_wallet);
 
     // Do not do anything to non-HD wallets
-    if (!pwallet->IsHDEnabled()) {
+    if (!pwallet->CanSupportFeature(FEATURE_HD)) {
         throw JSONRPCError(RPC_WALLET_ERROR, "Cannot set a HD seed on a non-HD wallet. Start with -upgradewallet in order to upgrade a non-HD wallet to HD");
     }
 
@@ -4184,7 +4200,7 @@ static const CRPCCommand commands[] =
     { "wallet",             "addmultisigaddress",               &addmultisigaddress,            {"nrequired","keys","label","address_type"} },
     { "wallet",             "backupwallet",                     &backupwallet,                  {"destination"} },
     { "wallet",             "bumpfee",                          &bumpfee,                       {"txid", "options"} },
-    { "wallet",             "createwallet",                     &createwallet,                  {"wallet_name", "disable_private_keys"} },
+    { "wallet",             "createwallet",                     &createwallet,                  {"wallet_name", "disable_private_keys", "blank"} },
     { "wallet",             "dumpprivkey",                      &dumpprivkey,                   {"address"}  },
     { "wallet",             "dumpwallet",                       &dumpwallet,                    {"filename"} },
     { "wallet",             "encryptwallet",                    &encryptwallet,                 {"passphrase"} },