Merge #13058: [wallet] `createwallet` RPC - create new wallet at runtime

f7e153e95 [wallets] [docs] Add release notes for createwallet RPC. (John Newbery)
32167e830 [wallet] [tests] Add tests for `createwallet` RPC. (John Newbery)
942131774 [wallet] [rpc] Add `createwallet` RPC (John Newbery)

Pull request description:

  Adds a `createwallet` RPC to dynamically create a new wallet at runtime.

  Includes tests and release notes.

Tree-SHA512: e0d89e3ae498234e9db5b827c56804cbab64f18a1875e2b5e676172c110278ea1b9e93a8a61b8dd80e2f2a691490bf229e923e4ccb284a1d3e420b8317815866

3 files changed, 77 insertions, 5 deletions

diff --git a/doc/release-notes-pr10740.md b/doc/release-notes-pr10740.md
index f286216b6e..c81ea6a4db 100644
--- a/doc/release-notes-pr10740.md
+++ b/doc/release-notes-pr10740.md
@@ -1,8 +1,9 @@
-Dynamic loading of wallets
---------------------------
+Dynamic loading and creation of wallets
+---------------------------------------
 
-Previously, wallets could only be loaded at startup, by specifying `-wallet` parameters on the command line or in the bitcoin.conf file. It is now possible to load wallets dynamically at runtime by calling the `loadwallet` RPC.
+Previously, wallets could only be loaded or created at startup, by specifying `-wallet` parameters on the command line or in the bitcoin.conf file. It is now possible to load and create wallets dynamically at runtime:
 
-The wallet can be specified as file/directory basename (which must be located in the `walletdir` directory), or as an absolute path to a file/directory.
+- Existing wallets can be loaded by calling the `loadwallet` RPC. The wallet can be specified as file/directory basename (which must be located in the `walletdir` directory), or as an absolute path to a file/directory.
+- New wallets can be created (and loaded) by calling the `createwallet` RPC. The provided name must not match a wallet file in the `walletdir` directory or the name of a wallet that is currently loaded.
 
-This feature is currently only available through the RPC interface. Wallets loaded in this way will display in the bitcoin-qt GUI.
+This feature is currently only available through the RPC interface.
diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
index 3809eb3dd7..456f08bc14 100644
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -3114,6 +3114,53 @@ UniValue loadwallet(const JSONRPCRequest& request)
     return obj;
 }
 
+UniValue createwallet(const JSONRPCRequest& request)
+{
+    if (request.fHelp || request.params.size() != 1) {
+        throw std::runtime_error(
+            "createwallet \"wallet_name\"\n"
+            "\nCreates and loads a new wallet.\n"
+            "\nArguments:\n"
+            "1. \"wallet_name\"    (string, required) The name for the new wallet. If this is a path, the wallet will be created at the path location.\n"
+            "\nResult:\n"
+            "{\n"
+            "  \"name\" :    <wallet_name>,        (string) The wallet name if created successfully. If the wallet was created using a full path, the wallet_name will be the full path.\n"
+            "  \"warning\" : <warning>,            (string) Warning message if wallet was not loaded cleanly.\n"
+            "}\n"
+            "\nExamples:\n"
+            + HelpExampleCli("createwallet", "\"testwallet\"")
+            + HelpExampleRpc("createwallet", "\"testwallet\"")
+        );
+    }
+    std::string wallet_name = request.params[0].get_str();
+    std::string error;
+    std::string warning;
+
+    fs::path wallet_path = fs::absolute(wallet_name, GetWalletDir());
+    if (fs::symlink_status(wallet_path).type() != fs::file_not_found) {
+        throw JSONRPCError(RPC_WALLET_ERROR, "Wallet " + wallet_name + " already exists.");
+    }
+
+    // Wallet::Verify will check if we're trying to create a wallet with a duplication name.
+    if (!CWallet::Verify(wallet_name, false, error, warning)) {
+        throw JSONRPCError(RPC_WALLET_ERROR, "Wallet file verification failed: " + error);
+    }
+
+    std::shared_ptr<CWallet> const wallet = CWallet::CreateWalletFromFile(wallet_name, fs::absolute(wallet_name, GetWalletDir()));
+    if (!wallet) {
+        throw JSONRPCError(RPC_WALLET_ERROR, "Wallet creation failed.");
+    }
+    AddWallet(wallet);
+
+    wallet->postInitProcess();
+
+    UniValue obj(UniValue::VOBJ);
+    obj.pushKV("name", wallet->GetName());
+    obj.pushKV("warning", warning);
+
+    return obj;
+}
+
 static UniValue resendwallettransactions(const JSONRPCRequest& request)
 {
     std::shared_ptr<CWallet> const wallet = GetWalletForJSONRPCRequest(request);
@@ -4315,6 +4362,7 @@ static const CRPCCommand commands[] =
     { "hidden",             "addwitnessaddress",                &addwitnessaddress,             {"address","p2sh"} },
     { "wallet",             "backupwallet",                     &backupwallet,                  {"destination"} },
     { "wallet",             "bumpfee",                          &bumpfee,                       {"txid", "options"} },
+    { "wallet",             "createwallet",                     &createwallet,                  {"wallet_name"} },
     { "wallet",             "dumpprivkey",                      &dumpprivkey,                   {"address"}  },
     { "wallet",             "dumpwallet",                       &dumpwallet,                    {"filename"} },
     { "wallet",             "encryptwallet",                    &encryptwallet,                 {"passphrase"} },
diff --git a/test/functional/wallet_multiwallet.py b/test/functional/wallet_multiwallet.py
index 5671773528..53638615f6 100755
--- a/test/functional/wallet_multiwallet.py
+++ b/test/functional/wallet_multiwallet.py
@@ -211,5 +211,28 @@ class MultiWalletTest(BitcoinTestFramework):
         # Fail to load if wallet file is a symlink
         assert_raises_rpc_error(-4, "Wallet file verification failed: Invalid -wallet path 'w8_symlink'", self.nodes[0].loadwallet, 'w8_symlink')
 
+        self.log.info("Test dynamic wallet creation.")
+
+        # Fail to create a wallet if it already exists.
+        assert_raises_rpc_error(-4, "Wallet w2 already exists.", self.nodes[0].createwallet, 'w2')
+
+        # Successfully create a wallet with a new name
+        loadwallet_name = self.nodes[0].createwallet('w9')
+        assert_equal(loadwallet_name['name'], 'w9')
+        w9 = node.get_wallet_rpc('w9')
+        assert_equal(w9.getwalletinfo()['walletname'], 'w9')
+
+        assert 'w9' in self.nodes[0].listwallets()
+
+        # Successfully create a wallet using a full path
+        new_wallet_dir = os.path.join(self.options.tmpdir, 'new_walletdir')
+        new_wallet_name = os.path.join(new_wallet_dir, 'w10')
+        loadwallet_name = self.nodes[0].createwallet(new_wallet_name)
+        assert_equal(loadwallet_name['name'], new_wallet_name)
+        w10 = node.get_wallet_rpc(new_wallet_name)
+        assert_equal(w10.getwalletinfo()['walletname'], new_wallet_name)
+
+        assert new_wallet_name in self.nodes[0].listwallets()
+
 if __name__ == '__main__':
     MultiWalletTest().main()