Merge bitcoin/bitcoin#29277: RPC: access RPC arguments by name

30a6c999351041d6a1e8712a9659be1296a1b46a rpc: access some args by name (stickies-v)
bbb31269bfa449e82d3b6a20c2c3481fb3dcc316 rpc: add named arg helper (stickies-v)
13525e0c248eab9b199583cde76430c6da2426e2 rpc: add arg helper unit test (stickies-v)

Pull request description:

  Adds string overloads for the `RPCHelpMan::Arg` and `RPCHelpMan::MaybeArg` helpers to be able to access RPC arguments by name instead of index number. Especially in RPCs with a large number of parameters, this can be quite helpful.

  Example usage:
  ```cpp
  const auto action{self.Arg<std::string>("action")};
  ```

  Most of the LoC is adding test coverage and documentation updates. No behaviour change.

  An alternative approach to #27788 with significantly less overhaul.

ACKs for top commit:
  fjahr:
    Code review ACK 30a6c999351041d6a1e8712a9659be1296a1b46a
  maflcko:
    ACK 30a6c999351041d6a1e8712a9659be1296a1b46a 🥑
  ryanofsky:
    Code review ACK 30a6c999351041d6a1e8712a9659be1296a1b46a. Nice change! Implementation is surprisingly simple and additional unit test coverage is welcome, too.

Tree-SHA512: 4904f5f914fe1d421d32f60edb7c5a028c8ea0f140a2f207a106b4752d441164e073066a6bf2e17693f859fe847815a96609d3cf521e0ac4178d8cd09362ea3d

1 files changed, 4 insertions, 4 deletions

diff --git a/src/rpc/mining.cpp b/src/rpc/mining.cpp
index f7cdbf52dd..454c262803 100644
--- a/src/rpc/mining.cpp
+++ b/src/rpc/mining.cpp
@@ -122,7 +122,7 @@ static RPCHelpMan getnetworkhashps()
 {
     ChainstateManager& chainman = EnsureAnyChainman(request.context);
     LOCK(cs_main);
-    return GetNetworkHashPS(self.Arg<int>(0), self.Arg<int>(1), chainman.ActiveChain());
+    return GetNetworkHashPS(self.Arg<int>("nblocks"), self.Arg<int>("height"), chainman.ActiveChain());
 },
     };
 }
@@ -229,12 +229,12 @@ static RPCHelpMan generatetodescriptor()
             "\nGenerate 11 blocks to mydesc\n" + HelpExampleCli("generatetodescriptor", "11 \"mydesc\"")},
         [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
 {
-    const auto num_blocks{self.Arg<int>(0)};
-    const auto max_tries{self.Arg<uint64_t>(2)};
+    const auto num_blocks{self.Arg<int>("num_blocks")};
+    const auto max_tries{self.Arg<uint64_t>("maxtries")};
 
     CScript coinbase_script;
     std::string error;
-    if (!getScriptFromDescriptor(self.Arg<std::string>(1), coinbase_script, error)) {
+    if (!getScriptFromDescriptor(self.Arg<std::string>("descriptor"), coinbase_script, error)) {
         throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, error);
     }