Merge #19133: rpc, cli, test: add bitcoin-cli -generate command

22cb303cf099b430d602384bc92706ce01b4f98d rpc: add missing space in JSON parsing error message, update test (Jon Atack)
bf53ebef061a563cfc4c5857f5d6bc93fb136282 test: add multiwallet tests for bitcoin-cli -generate (Jon Atack)
4b859cfff9965eb07044f4d104398cb0e7ab127e cli: add multiwallet capability to GetNewAddress and -generate (Jon Atack)
18f93545a12db00180cea369a4b5cce7f10cd362 test: add tests for bitcoin-cli -generate (Jon Atack)
4818124137732540383a29835afa2be41aa55ca8 cli: create bitcoin-cli -generate command (Jon Atack)
ff41a3690066081772b172f3c31a63f5fe6ea7ed cli: extract ParseResult() and ParseError() (Jon Atack)
f4185b26d9b2ff2e86c99cdfe3ad9be62bb6299a cli: create GenerateToAddressRequestHandler class (Harris)
f7c65a33508c4bb8e9ed896e150a4fa529a243e5 cli: create GetNewAddress() (Jon Atack)
9be7fd35c5d631c2cc34d3b4fa63ae0a9d5a68ef rpc: make generatetoaddress locals const (Jon Atack)
cb00510dbac99b44f3f2cf6e58bb2e4401c5ef28 rpc: create rpc/mining.h, hoist default max tries values to constant (Jon Atack)

Pull request description:

  This PR continues and completes the work begun in #17700 working on issue #16000 to create a client-side version of RPC `generate`.

  Basically, `bitcoin-cli -generate` wraps calling `generatenewaddress` followed by `generatetoaddress [nblocks] [maxtries]` and prints the following:

  ```
  $ bitcoin-cli -generate
  {
    "address": "bcrt1qn4aszr2y2xvpa70y675a76wsu70wlkwvdyyln6"
    "blocks": [
      "01d2ebcddf663da90b28da7f6805115e2ba7818f16fe747258836646a43a0bb5",
    ]
  }

  $ bitcoin-cli -rpcwallet=wallet-name -generate 3 100
  {
    "address": "bcrt1q4cunfw0gnsj7g7e6mk0v0uuvvau9mwr09dj45l",
    "blocks": [
      "7a6650ca5e0c614992ee64fb148a7e5e022af842e4b6003f81abd8baf1e75136",
      "01d2ebcddf663da90b28da7f6805115e2ba7818f16fe747258836646a43a0bb5",
      "3f8795ec40b1ad812b818c177680841be319a3f6753d4e32dc7dfb5bafe5d00e"
    ]
  }
  ```

  Help doc:
  ```
  $ bitcoin-cli -h | grep -A5 "\-generate"
    -generate
         Generate blocks immediately, equivalent to RPC generatenewaddress
         followed by RPC generatetoaddress. Optional positional arguments
         are number of blocks to generate (default: 1) and maximum
         iterations to try (default: 1000000), equivalent to RPC
         generatetoaddress nblocks and maxtries arguments. Example:
         bitcoin-cli -generate 4 1000
  ```

  Quite a bit of test coverage turned out to be needed to cover the change and the different cases (arguments, multiwallet mode) and error-handling.

  This PR also improves some things that working on these changes brought to light.

  Credit to Harris Brakmić for the initial work in #17700.

ACKs for top commit:
  adamjonas:
    utACK 22cb303cf099b430d602384bc92706ce01b4f98d
  meshcollider:
    utACK 22cb303cf099b430d602384bc92706ce01b4f98d

Tree-SHA512: 94f67f632fe093d076f614e0ecff09ce7342ac6e424579200d5211a6615260e438d857861767fb788950ec6da0b26ef56dc8268c430012a3b3d4822b24ca6fbf

5 files changed, 127 insertions, 43 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index a33ff8a461..632ed3e31f 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -184,6 +184,7 @@ BITCOIN_CORE_H = \
   reverse_iterator.h \
   rpc/blockchain.h \
   rpc/client.h \
+  rpc/mining.h \
   rpc/protocol.h \
   rpc/rawtransaction_util.h \
   rpc/register.h \
diff --git a/src/bitcoin-cli.cpp b/src/bitcoin-cli.cpp
index 8d85789b4e..f5125f22db 100644
--- a/src/bitcoin-cli.cpp
+++ b/src/bitcoin-cli.cpp
@@ -11,6 +11,7 @@
 #include <clientversion.h>
 #include <optional.h>
 #include <rpc/client.h>
+#include <rpc/mining.h>
 #include <rpc/protocol.h>
 #include <rpc/request.h>
 #include <util/strencodings.h>
@@ -39,6 +40,9 @@ static const int DEFAULT_HTTP_CLIENT_TIMEOUT=900;
 static const bool DEFAULT_NAMED=false;
 static const int CONTINUE_EXECUTION=-1;
 
+/** Default number of blocks to generate for RPC generatetoaddress. */
+static const std::string DEFAULT_NBLOCKS = "1";
+
 static void SetupCliArgs()
 {
     SetupHelpOptions(gArgs);
@@ -50,6 +54,7 @@ static void SetupCliArgs()
     gArgs.AddArg("-version", "Print version and exit", ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     gArgs.AddArg("-conf=<file>", strprintf("Specify configuration file. Relative paths will be prefixed by datadir location. (default: %s)", BITCOIN_CONF_FILENAME), ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     gArgs.AddArg("-datadir=<dir>", "Specify data directory", ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
+    gArgs.AddArg("-generate", strprintf("Generate blocks immediately, equivalent to RPC generatenewaddress followed by RPC generatetoaddress. Optional positional integer arguments are number of blocks to generate (default: %s) and maximum iterations to try (default: %s), equivalent to RPC generatetoaddress nblocks and maxtries arguments. Example: bitcoin-cli -generate 4 1000", DEFAULT_NBLOCKS, DEFAULT_MAX_TRIES), ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     gArgs.AddArg("-getinfo", "Get general information from the remote server. Note that unlike server-side RPC calls, the results of -getinfo is the result of multiple non-atomic requests. Some entries in the result may represent results from different states (e.g. wallet balance may be as of a different block from the chain state reported)", ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     SetupChainParamsBaseOptions();
     gArgs.AddArg("-named", strprintf("Pass named instead of positional arguments (default: %s)", DEFAULT_NAMED), ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
@@ -286,6 +291,28 @@ public:
     }
 };
 
+/** Process RPC generatetoaddress request. */
+class GenerateToAddressRequestHandler : public BaseRequestHandler
+{
+public:
+    UniValue PrepareRequest(const std::string& method, const std::vector<std::string>& args) override
+    {
+        address_str = args.at(1);
+        UniValue params{RPCConvertValues("generatetoaddress", args)};
+        return JSONRPCRequestObj("generatetoaddress", params, 1);
+    }
+
+    UniValue ProcessReply(const UniValue &reply) override
+    {
+        UniValue result(UniValue::VOBJ);
+        result.pushKV("address", address_str);
+        result.pushKV("blocks", reply.get_obj()["result"]);
+        return JSONRPCReplyObj(result, NullUniValue, 1);
+    }
+protected:
+    std::string address_str;
+};
+
 /** Process default single requests */
 class DefaultRequestHandler: public BaseRequestHandler {
 public:
@@ -453,6 +480,34 @@ static UniValue ConnectAndCallRPC(BaseRequestHandler* rh, const std::string& str
     return response;
 }
 
+/** Parse UniValue result to update the message to print to std::cout. */
+static void ParseResult(const UniValue& result, std::string& strPrint)
+{
+    if (result.isNull()) return;
+    strPrint = result.isStr() ? result.get_str() : result.write(2);
+}
+
+/** Parse UniValue error to update the message to print to std::cerr and the code to return. */
+static void ParseError(const UniValue& error, std::string& strPrint, int& nRet)
+{
+    if (error.isObject()) {
+        const UniValue& err_code = find_value(error, "code");
+        const UniValue& err_msg = find_value(error, "message");
+        if (!err_code.isNull()) {
+            strPrint = "error code: " + err_code.getValStr() + "\n";
+        }
+        if (err_msg.isStr()) {
+            strPrint += ("error message:\n" + err_msg.get_str());
+        }
+        if (err_code.isNum() && err_code.get_int() == RPC_WALLET_NOT_SPECIFIED) {
+            strPrint += "\nTry adding \"-rpcwallet=<filename>\" option to bitcoin-cli command line.";
+        }
+    } else {
+        strPrint = "error: " + error.write();
+    }
+    nRet = abs(error["code"].get_int());
+}
+
 /**
  * GetWalletBalances calls listwallets; if more than one wallet is loaded, it then
  * fetches mine.trusted balances for each loaded wallet and pushes them to `result`.
@@ -477,6 +532,34 @@ static void GetWalletBalances(UniValue& result)
     result.pushKV("balances", balances);
 }
 
+/**
+ * Call RPC getnewaddress.
+ * @returns getnewaddress response as a UniValue object.
+ */
+static UniValue GetNewAddress()
+{
+    Optional<std::string> wallet_name{};
+    if (gArgs.IsArgSet("-rpcwallet")) wallet_name = gArgs.GetArg("-rpcwallet", "");
+    std::unique_ptr<BaseRequestHandler> rh{MakeUnique<DefaultRequestHandler>()};
+    return ConnectAndCallRPC(rh.get(), "getnewaddress", /* args=*/{}, wallet_name);
+}
+
+/**
+ * Check bounds and set up args for RPC generatetoaddress params: nblocks, address, maxtries.
+ * @param[in] address  Reference to const string address to insert into the args.
+ * @param     args     Reference to vector of string args to modify.
+ */
+static void SetGenerateToAddressArgs(const std::string& address, std::vector<std::string>& args)
+{
+    if (args.size() > 2) throw std::runtime_error("too many arguments (maximum 2 for nblocks and maxtries)");
+    if (args.size() == 0) {
+        args.emplace_back(DEFAULT_NBLOCKS);
+    } else if (args.at(0) == "0") {
+        throw std::runtime_error("the first argument (number of blocks to generate, default: " + DEFAULT_NBLOCKS + ") must be an integer value greater than zero");
+    }
+    args.emplace(args.begin() + 1, address);
+}
+
 static int CommandLineRPC(int argc, char *argv[])
 {
     std::string strPrint;
@@ -535,6 +618,15 @@ static int CommandLineRPC(int argc, char *argv[])
         std::string method;
         if (gArgs.IsArgSet("-getinfo")) {
             rh.reset(new GetinfoRequestHandler());
+        } else if (gArgs.GetBoolArg("-generate", false)) {
+            const UniValue getnewaddress{GetNewAddress()};
+            const UniValue& error{find_value(getnewaddress, "error")};
+            if (error.isNull()) {
+                SetGenerateToAddressArgs(find_value(getnewaddress, "result").get_str(), args);
+                rh.reset(new GenerateToAddressRequestHandler());
+            } else {
+                ParseError(error, strPrint, nRet);
+            }
         } else {
             rh.reset(new DefaultRequestHandler());
             if (args.size() < 1) {
@@ -543,40 +635,22 @@ static int CommandLineRPC(int argc, char *argv[])
             method = args[0];
             args.erase(args.begin()); // Remove trailing method name from arguments vector
         }
-        Optional<std::string> wallet_name{};
-        if (gArgs.IsArgSet("-rpcwallet")) wallet_name = gArgs.GetArg("-rpcwallet", "");
-        const UniValue reply = ConnectAndCallRPC(rh.get(), method, args, wallet_name);
-
-        // Parse reply
-        UniValue result = find_value(reply, "result");
-        const UniValue& error = find_value(reply, "error");
-        if (!error.isNull()) {
-            // Error
-            strPrint = "error: " + error.write();
-            nRet = abs(error["code"].get_int());
-            if (error.isObject()) {
-                const UniValue& errCode = find_value(error, "code");
-                const UniValue& errMsg = find_value(error, "message");
-                strPrint = errCode.isNull() ? "" : ("error code: " + errCode.getValStr() + "\n");
-
-                if (errMsg.isStr()) {
-                    strPrint += ("error message:\n" + errMsg.get_str());
-                }
-                if (errCode.isNum() && errCode.get_int() == RPC_WALLET_NOT_SPECIFIED) {
-                    strPrint += "\nTry adding \"-rpcwallet=<filename>\" option to bitcoin-cli command line.";
+        if (nRet == 0) {
+            // Perform RPC call
+            Optional<std::string> wallet_name{};
+            if (gArgs.IsArgSet("-rpcwallet")) wallet_name = gArgs.GetArg("-rpcwallet", "");
+            const UniValue reply = ConnectAndCallRPC(rh.get(), method, args, wallet_name);
+
+            // Parse reply
+            UniValue result = find_value(reply, "result");
+            const UniValue& error = find_value(reply, "error");
+            if (error.isNull()) {
+                if (gArgs.IsArgSet("-getinfo") && !gArgs.IsArgSet("-rpcwallet")) {
+                    GetWalletBalances(result); // fetch multiwallet balances and append to result
                 }
-            }
-        } else {
-            if (gArgs.IsArgSet("-getinfo") && !gArgs.IsArgSet("-rpcwallet")) {
-                GetWalletBalances(result); // fetch multiwallet balances and append to result
-            }
-            // Result
-            if (result.isNull()) {
-                strPrint = "";
-            } else if (result.isStr()) {
-                strPrint = result.get_str();
+                ParseResult(result, strPrint);
             } else {
-                strPrint = result.write(2);
+                ParseError(error, strPrint, nRet);
             }
         }
     } catch (const std::exception& e) {
diff --git a/src/rpc/client.cpp b/src/rpc/client.cpp
index 3045a74d7a..66ace7263a 100644
--- a/src/rpc/client.cpp
+++ b/src/rpc/client.cpp
@@ -217,7 +217,7 @@ UniValue ParseNonRFCJSONValue(const std::string& strVal)
     UniValue jVal;
     if (!jVal.read(std::string("[")+strVal+std::string("]")) ||
         !jVal.isArray() || jVal.size()!=1)
-        throw std::runtime_error(std::string("Error parsing JSON:")+strVal);
+        throw std::runtime_error(std::string("Error parsing JSON: ") + strVal);
     return jVal[0];
 }
 
diff --git a/src/rpc/mining.cpp b/src/rpc/mining.cpp
index d5fc3f57bb..e8e0ab3179 100644
--- a/src/rpc/mining.cpp
+++ b/src/rpc/mining.cpp
@@ -17,6 +17,7 @@
 #include <policy/fees.h>
 #include <pow.h>
 #include <rpc/blockchain.h>
+#include <rpc/mining.h>
 #include <rpc/server.h>
 #include <rpc/util.h>
 #include <script/descriptor.h>
@@ -207,7 +208,7 @@ static UniValue generatetodescriptor(const JSONRPCRequest& request)
         {
             {"num_blocks", RPCArg::Type::NUM, RPCArg::Optional::NO, "How many blocks are generated immediately."},
             {"descriptor", RPCArg::Type::STR, RPCArg::Optional::NO, "The descriptor to send the newly generated bitcoin to."},
-            {"maxtries", RPCArg::Type::NUM, /* default */ "1000000", "How many iterations to try."},
+            {"maxtries", RPCArg::Type::NUM, /* default */ ToString(DEFAULT_MAX_TRIES), "How many iterations to try."},
         },
         RPCResult{
             RPCResult::Type::ARR, "", "hashes of blocks generated",
@@ -221,7 +222,7 @@ static UniValue generatetodescriptor(const JSONRPCRequest& request)
         .Check(request);
 
     const int num_blocks{request.params[0].get_int()};
-    const int64_t max_tries{request.params[2].isNull() ? 1000000 : request.params[2].get_int()};
+    const uint64_t max_tries{request.params[2].isNull() ? DEFAULT_MAX_TRIES : request.params[2].get_int()};
 
     CScript coinbase_script;
     std::string error;
@@ -242,7 +243,7 @@ static UniValue generatetoaddress(const JSONRPCRequest& request)
                 {
                     {"nblocks", RPCArg::Type::NUM, RPCArg::Optional::NO, "How many blocks are generated immediately."},
                     {"address", RPCArg::Type::STR, RPCArg::Optional::NO, "The address to send the newly generated bitcoin to."},
-                    {"maxtries", RPCArg::Type::NUM, /* default */ "1000000", "How many iterations to try."},
+                    {"maxtries", RPCArg::Type::NUM, /* default */ ToString(DEFAULT_MAX_TRIES), "How many iterations to try."},
                 },
                 RPCResult{
                     RPCResult::Type::ARR, "", "hashes of blocks generated",
@@ -257,11 +258,8 @@ static UniValue generatetoaddress(const JSONRPCRequest& request)
                 },
             }.Check(request);
 
-    int nGenerate = request.params[0].get_int();
-    uint64_t nMaxTries = 1000000;
-    if (!request.params[2].isNull()) {
-        nMaxTries = request.params[2].get_int();
-    }
+    const int num_blocks{request.params[0].get_int()};
+    const uint64_t max_tries{request.params[2].isNull() ? DEFAULT_MAX_TRIES : request.params[2].get_int()};
 
     CTxDestination destination = DecodeDestination(request.params[1].get_str());
     if (!IsValidDestination(destination)) {
@@ -273,7 +271,7 @@ static UniValue generatetoaddress(const JSONRPCRequest& request)
 
     CScript coinbase_script = GetScriptForDestination(destination);
 
-    return generateBlocks(chainman, mempool, coinbase_script, nGenerate, nMaxTries);
+    return generateBlocks(chainman, mempool, coinbase_script, num_blocks, max_tries);
 }
 
 static UniValue generateblock(const JSONRPCRequest& request)
@@ -371,7 +369,7 @@ static UniValue generateblock(const JSONRPCRequest& request)
     }
 
     uint256 block_hash;
-    uint64_t max_tries{1000000};
+    uint64_t max_tries{DEFAULT_MAX_TRIES};
     unsigned int extra_nonce{0};
 
     if (!GenerateBlock(EnsureChainman(request.context), block, max_tries, extra_nonce, block_hash) || block_hash.IsNull()) {
diff --git a/src/rpc/mining.h b/src/rpc/mining.h
new file mode 100644
index 0000000000..acc74e1dcc
--- /dev/null
+++ b/src/rpc/mining.h
@@ -0,0 +1,11 @@
+// Copyright (c) 2020 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_RPC_MINING_H
+#define BITCOIN_RPC_MINING_H
+
+/** Default max iterations to try in RPC generatetodescriptor, generatetoaddress, and generateblock. */
+static const uint64_t DEFAULT_MAX_TRIES{1000000};
+
+#endif // BITCOIN_RPC_MINING_H