Merge #15226: Allow creating blank (empty) wallets (alternative)

7687f7873 [wallet] Support creating a blank wallet (Andrew Chow)

Pull request description:

  Alternative (kind of) to #14938

  This PR adds a `blank` parameter to the `createwallet` RPC to create a wallet that has no private keys initially. `sethdseed` can then be used to make a clean wallet with a custom seed. `encryptwallet` can also be used to make a wallet that is born encrypted.

  Instead of changing the version number as done in #14938, a wallet flag is used to indicate that the wallet should be blank. This flag is set at creation, and then unset when the wallet is no longer blank. A wallet becomes non-blank when a HD seed is set or anything is imported. The main change to create a blank wallet is primarily taken from #14938.

  Also with this, the term "blank wallet" is used instead of "empty wallet" to avoid confusion with wallets that have balance which would also be referred to as "empty".

  This is built on top of #15225 in order to fix GUI issues.

Tree-SHA512: 824d685e11ac2259a26b5ece99c67a7bda94a570cd921472c464243ee356b7734595ad35cc439b34357135df041ed9cba951e6edac194935c3a55a1dc4fcbdea

1 files changed, 23 insertions, 7 deletions

diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
index b9d993dc9c..9bbbdc6132 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.");
     }
@@ -3886,7 +3902,7 @@ 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");
     }
 
@@ -4190,7 +4206,7 @@ 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"} },