Merge bitcoin/bitcoin#25737: rpc: treat univalue type check error as RPC_TYPE_ERROR, not RPC_MISC_ERROR

e68d380797918e655decb76fc11725197d6d5323 rpc: remove unneeded RPCTypeCheckArgument checks (furszy)
55566630c60d23993a52ed54c95e7891f4588d57 rpc: treat univalue type check error as RPC_TYPE_ERROR, not RPC_MISC_ERROR (furszy)

Pull request description:

  Same rationale as #26039, tackling another angle of the problem.

  #### Context
  We have the same univalue type error checking code spread/duplicated few times:
  `RPCTypeCheckObj`, `RPCTypeCheckArgument`, `UniValue::checkType`.

  In the first two functions, we are properly returning an `RPC_TYPE_ERROR` while in `UniValue::checkType`
  we are throwing an `std::runtime_error` which is caught by the RPC server request handler, who invalidly
  treats it as `RPC_MISC_ERROR` (which is a generic error return code that provides no information to the user).

  #### Proposed Changes

  Throw a custom exception from `Univalue::checkType` (instead of a plain
  `std::runtime_error`) and catch it on the RPC server request handler.

  So we properly return `RPC_TYPE_ERROR` (-3) on every arg type error and
  not the general `RPC_MISC_ERROR` (-1).

  This will allow us to remove all the `RPCTypeCheckArgument` calls. As them are redundant since #25629.

Top commit has no ACKs.

Tree-SHA512: 4e4c41851fd4e2b01a2d8b94e71513f9831f810768ebd89684caca4901e87d3677980003949bcce441f9ca607a1b38a5894839b6c492f5947b8bab8cd9423ba6

1 files changed, 5 insertions, 0 deletions

diff --git a/src/univalue/include/univalue.h b/src/univalue/include/univalue.h
index ccaf56a271..850d0a1cbc 100644
--- a/src/univalue/include/univalue.h
+++ b/src/univalue/include/univalue.h
@@ -19,6 +19,11 @@ class UniValue {
 public:
     enum VType { VNULL, VOBJ, VARR, VSTR, VNUM, VBOOL, };
 
+    class type_error : public std::runtime_error
+    {
+        using std::runtime_error::runtime_error;
+    };
+
     UniValue() { typ = VNULL; }
     UniValue(UniValue::VType initialType, const std::string& initialStr = "") {
         typ = initialType;