Merge #15401: rpc: Actually throw help when passed invalid number of params

fa4ce7038d444defe0b98a30097174c278054a33 rpc: Actually throw help when passed invalid number of params (MarcoFalke)
fa05626ca7a0fe896ac554c79eaea4c36acdf861 rpc: Add RPCHelpMan::IsValidNumArgs() (MarcoFalke)

Pull request description:

  Can be tested by

  * running the included test against an old binary (compiled without this patch)
  * calling `setban 1 "add" 3 4 5 6 7 8 9 0` in the gui

Tree-SHA512: aa6a25bbe6f40722913ea292252a62a4012c964eed9f4035335a2e2d13be98eb60f368e8a3251a104a26a62c08b2cb926b06e5ab1418ef1cf4abdd71d87c2919

1 files changed, 6 insertions, 2 deletions

diff --git a/src/rpc/util.h b/src/rpc/util.h
index a83ae98b7e..06800ad63c 100644
--- a/src/rpc/util.h
+++ b/src/rpc/util.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2017-2018 The Bitcoin Core developers
+// Copyright (c) 2017-2019 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
@@ -54,7 +54,7 @@ struct RPCArg {
         /** Required arg */
         NO,
         /**
-         * Optinal arg that is a named argument and has a default value of
+         * Optional arg that is a named argument and has a default value of
          * `null`. When possible, the default value should be specified.
          */
         OMITTED_NAMED_ARG,
@@ -111,6 +111,8 @@ struct RPCArg {
         assert(type == Type::ARR || type == Type::OBJ);
     }
 
+    bool IsOptional() const;
+
     /**
      * Return the type string of the argument.
      * Set oneline to allow it to be overridden by a custom oneline type string (m_oneline_description).
@@ -186,6 +188,8 @@ public:
     RPCHelpMan(std::string name, std::string description, std::vector<RPCArg> args, RPCResults results, RPCExamples examples);
 
     std::string ToString() const;
+    /** If the supplied number of args is neither too small nor too high */
+    bool IsValidNumArgs(size_t num_args) const;
 
 private:
     const std::string m_name;