Merge bitcoin/bitcoin#30238: json-rpc 2.0 followups: docs, tests, cli

1f6ab1215bbb1f8a5f1743c3c413b95ad08090df minor: remove unnecessary semicolons from RPC content type examples (Matthew Zipkin)
b22529529823c0cb5916ac318c8536e9107b7e78 test: use json-rpc 2.0 in all functional tests by default (Matthew Zipkin)
391843b0297db03d71a8d88ab77609e2ad230bf2 bitcoin-cli: use json-rpc 2.0 (Matthew Zipkin)
d39bdf339772166a5545ae811e58b7764af093a8 test: remove unused variable in interface_rpc.py (Matthew Zipkin)
0ead71df8c83a2f9eae1220544ec84dcf38a0326 doc: update and link for JSON-RPC 2.0 (Matthew Zipkin)

Pull request description:

  This is a follow-up to #27101.

  - Addresses [post-merge comments ](https://github.com/bitcoin/bitcoin/pull/27101#discussion_r1606723428)
  - bitcoin-cli uses JSON-RPC 2.0
  - functional tests use JSON-RPC 2.0 by default (exceptions are in the regression tests added by #27101)

ACKs for top commit:
  tdb3:
    ACK 1f6ab1215bbb1f8a5f1743c3c413b95ad08090df
  cbergqvist:
    ACK 1f6ab1215bbb1f8a5f1743c3c413b95ad08090df

Tree-SHA512: 49bf14c70464081280216ece538a2f5ec810bac80a86a83ad3284f0f1b017edf755a1a74a45be279effe00218170cafde7c2de58aed07097a95c2c6b837a6b6c

9 files changed, 41 insertions, 30 deletions

diff --git a/doc/JSON-RPC-interface.md b/doc/JSON-RPC-interface.md
index 2a97aa351d..10d8ee52eb 100644
--- a/doc/JSON-RPC-interface.md
+++ b/doc/JSON-RPC-interface.md
@@ -33,10 +33,10 @@ requests when multiple wallets are in use.
 
 ```sh
 # Get block count from the / endpoint when rpcuser=alice and rpcport=38332
-$ curl --user alice --data-binary '{"jsonrpc": "1.0", "id": "0", "method": "getblockcount", "params": []}' -H 'content-type: application/json;' localhost:38332/
+$ curl --user alice --data-binary '{"jsonrpc": "2.0", "id": "0", "method": "getblockcount", "params": []}' -H 'content-type: application/json' localhost:38332/
 
 # Get balance from the /wallet/walletname endpoint when rpcuser=alice, rpcport=38332 and rpcwallet=desc-wallet
-$ curl --user alice --data-binary '{"jsonrpc": "1.0", "id": "0", "method": "getbalance", "params": []}' -H 'content-type: application/json;' localhost:38332/wallet/desc-wallet
+$ curl --user alice --data-binary '{"jsonrpc": "2.0", "id": "0", "method": "getbalance", "params": []}' -H 'content-type: application/json' localhost:38332/wallet/desc-wallet
 
 ```
 
@@ -80,7 +80,7 @@ The server recognizes [JSON-RPC v2.0](https://www.jsonrpc.org/specification) req
 and responds accordingly. A 2.0 request is identified by the presence of
 `"jsonrpc": "2.0"` in the request body. If that key + value is not present in a request,
 the legacy JSON-RPC v1.1 protocol is followed instead, which was the only available
-protocol in previous releases.
+protocol in v27.0 and prior releases.
 
 || 1.1 | 2.0 |
 |-|-|-|
@@ -88,7 +88,7 @@ protocol in previous releases.
 | Response marker | (none) | `"jsonrpc": "2.0"` |
 | `"error"` and `"result"` fields in response | both present | only one is present |
 | HTTP codes in response | `200` unless there is any kind of RPC error (invalid parameters, method not found, etc) | Always `200` unless there is an actual HTTP server error (request parsing error, endpoint not found, etc) |
-| Notifications: requests that get no reply | (not supported) | Supported for requests that exclude the "id" field |
+| Notifications: requests that get no reply | (not supported) | Supported for requests that exclude the "id" field. Returns HTTP status `204` "No Content" |
 
 ## Security
 
diff --git a/doc/release-notes-27101.md b/doc/release-notes-27101.md
index 8775b59c00..7ce1e9a8c1 100644
--- a/doc/release-notes-27101.md
+++ b/doc/release-notes-27101.md
@@ -2,8 +2,5 @@ JSON-RPC
 --------
 
 The JSON-RPC server now recognizes JSON-RPC 2.0 requests and responds with
-strict adherence to the specification (https://www.jsonrpc.org/specification):
-
-- Returning HTTP "204 No Content" responses to JSON-RPC 2.0 notifications instead of full responses.
-- Returning HTTP "200 OK" responses in all other cases, rather than 404 responses for unknown methods, 500 responses for invalid parameters, etc.
-- Returning either "result" fields or "error" fields in JSON-RPC responses, rather than returning both fields with one field set to null.
+strict adherence to the [specification](https://www.jsonrpc.org/specification).
+See [JSON-RPC-interface.md](/doc/JSON-RPC-interface.md#json-rpc-11-vs-20) for details.
\ No newline at end of file
diff --git a/src/bitcoin-cli.cpp b/src/bitcoin-cli.cpp
index cc639d8793..4c7f3717f6 100644
--- a/src/bitcoin-cli.cpp
+++ b/src/bitcoin-cli.cpp
@@ -298,7 +298,7 @@ public:
         }
         addresses.pushKV("total", total);
         result.pushKV("addresses_known", std::move(addresses));
-        return JSONRPCReplyObj(std::move(result), NullUniValue, /*id=*/1, JSONRPCVersion::V1_LEGACY);
+        return JSONRPCReplyObj(std::move(result), NullUniValue, /*id=*/1, JSONRPCVersion::V2);
     }
 };
 
@@ -367,7 +367,7 @@ public:
         }
         result.pushKV("relayfee", batch[ID_NETWORKINFO]["result"]["relayfee"]);
         result.pushKV("warnings", batch[ID_NETWORKINFO]["result"]["warnings"]);
-        return JSONRPCReplyObj(std::move(result), NullUniValue,  /*id=*/1, JSONRPCVersion::V1_LEGACY);
+        return JSONRPCReplyObj(std::move(result), NullUniValue,  /*id=*/1, JSONRPCVersion::V2);
     }
 };
 
@@ -622,7 +622,7 @@ public:
             }
         }
 
-        return JSONRPCReplyObj(UniValue{result}, NullUniValue, /*id=*/1, JSONRPCVersion::V1_LEGACY);
+        return JSONRPCReplyObj(UniValue{result}, NullUniValue, /*id=*/1, JSONRPCVersion::V2);
     }
 
     const std::string m_help_doc{
@@ -709,7 +709,7 @@ public:
         UniValue result(UniValue::VOBJ);
         result.pushKV("address", address_str);
         result.pushKV("blocks", reply.get_obj()["result"]);
-        return JSONRPCReplyObj(std::move(result), NullUniValue, /*id=*/1, JSONRPCVersion::V1_LEGACY);
+        return JSONRPCReplyObj(std::move(result), NullUniValue, /*id=*/1, JSONRPCVersion::V2);
     }
 protected:
     std::string address_str;
diff --git a/src/rpc/request.cpp b/src/rpc/request.cpp
index d35782189e..87b9f18b33 100644
--- a/src/rpc/request.cpp
+++ b/src/rpc/request.cpp
@@ -45,6 +45,7 @@ UniValue JSONRPCRequestObj(const std::string& strMethod, const UniValue& params,
     request.pushKV("method", strMethod);
     request.pushKV("params", params);
     request.pushKV("id", id);
+    request.pushKV("jsonrpc", "2.0");
     return request;
 }
 
diff --git a/src/rpc/request.h b/src/rpc/request.h
index e47f90af86..9968426636 100644
--- a/src/rpc/request.h
+++ b/src/rpc/request.h
@@ -17,6 +17,7 @@ enum class JSONRPCVersion {
     V2
 };
 
+/** JSON-RPC 2.0 request, only used in bitcoin-cli **/
 UniValue JSONRPCRequestObj(const std::string& strMethod, const UniValue& params, const UniValue& id);
 UniValue JSONRPCReplyObj(UniValue result, UniValue error, std::optional<UniValue> id, JSONRPCVersion jsonrpc_version);
 UniValue JSONRPCError(int code, const std::string& message);
diff --git a/src/rpc/util.cpp b/src/rpc/util.cpp
index 9600258de9..9123bddff4 100644
--- a/src/rpc/util.cpp
+++ b/src/rpc/util.cpp
@@ -176,7 +176,7 @@ std::string HelpExampleCliNamed(const std::string& methodname, const RPCArgList&
 std::string HelpExampleRpc(const std::string& methodname, const std::string& args)
 {
     return "> curl --user myusername --data-binary '{\"jsonrpc\": \"2.0\", \"id\": \"curltest\", "
-        "\"method\": \"" + methodname + "\", \"params\": [" + args + "]}' -H 'content-type: application/json;' http://127.0.0.1:8332/\n";
+        "\"method\": \"" + methodname + "\", \"params\": [" + args + "]}' -H 'content-type: application/json' http://127.0.0.1:8332/\n";
 }
 
 std::string HelpExampleRpcNamed(const std::string& methodname, const RPCArgList& args)
@@ -187,7 +187,7 @@ std::string HelpExampleRpcNamed(const std::string& methodname, const RPCArgList&
     }
 
     return "> curl --user myusername --data-binary '{\"jsonrpc\": \"2.0\", \"id\": \"curltest\", "
-           "\"method\": \"" + methodname + "\", \"params\": " + params.write() + "}' -H 'content-type: application/json;' http://127.0.0.1:8332/\n";
+           "\"method\": \"" + methodname + "\", \"params\": " + params.write() + "}' -H 'content-type: application/json' http://127.0.0.1:8332/\n";
 }
 
 // Converts a hex string to a public key if possible
diff --git a/src/test/rpc_tests.cpp b/src/test/rpc_tests.cpp
index efa078ca74..0f4c19e197 100644
--- a/src/test/rpc_tests.cpp
+++ b/src/test/rpc_tests.cpp
@@ -552,7 +552,7 @@ BOOST_AUTO_TEST_CASE(help_example)
     // test different argument types
     const RPCArgList& args = {{"foo", "bar"}, {"b", true}, {"n", 1}};
     BOOST_CHECK_EQUAL(HelpExampleCliNamed("test", args), "> bitcoin-cli -named test foo=bar b=true n=1\n");
-    BOOST_CHECK_EQUAL(HelpExampleRpcNamed("test", args), "> curl --user myusername --data-binary '{\"jsonrpc\": \"2.0\", \"id\": \"curltest\", \"method\": \"test\", \"params\": {\"foo\":\"bar\",\"b\":true,\"n\":1}}' -H 'content-type: application/json;' http://127.0.0.1:8332/\n");
+    BOOST_CHECK_EQUAL(HelpExampleRpcNamed("test", args), "> curl --user myusername --data-binary '{\"jsonrpc\": \"2.0\", \"id\": \"curltest\", \"method\": \"test\", \"params\": {\"foo\":\"bar\",\"b\":true,\"n\":1}}' -H 'content-type: application/json' http://127.0.0.1:8332/\n");
 
     // test shell escape
     BOOST_CHECK_EQUAL(HelpExampleCliNamed("test", {{"foo", "b'ar"}}), "> bitcoin-cli -named test foo='b'''ar'\n");
@@ -565,7 +565,7 @@ BOOST_AUTO_TEST_CASE(help_example)
     obj_value.pushKV("b", false);
     obj_value.pushKV("n", 1);
     BOOST_CHECK_EQUAL(HelpExampleCliNamed("test", {{"name", obj_value}}), "> bitcoin-cli -named test name='{\"foo\":\"bar\",\"b\":false,\"n\":1}'\n");
-    BOOST_CHECK_EQUAL(HelpExampleRpcNamed("test", {{"name", obj_value}}), "> curl --user myusername --data-binary '{\"jsonrpc\": \"2.0\", \"id\": \"curltest\", \"method\": \"test\", \"params\": {\"name\":{\"foo\":\"bar\",\"b\":false,\"n\":1}}}' -H 'content-type: application/json;' http://127.0.0.1:8332/\n");
+    BOOST_CHECK_EQUAL(HelpExampleRpcNamed("test", {{"name", obj_value}}), "> curl --user myusername --data-binary '{\"jsonrpc\": \"2.0\", \"id\": \"curltest\", \"method\": \"test\", \"params\": {\"name\":{\"foo\":\"bar\",\"b\":false,\"n\":1}}}' -H 'content-type: application/json' http://127.0.0.1:8332/\n");
 
     // test array params
     UniValue arr_value(UniValue::VARR);
@@ -573,7 +573,7 @@ BOOST_AUTO_TEST_CASE(help_example)
     arr_value.push_back(false);
     arr_value.push_back(1);
     BOOST_CHECK_EQUAL(HelpExampleCliNamed("test", {{"name", arr_value}}), "> bitcoin-cli -named test name='[\"bar\",false,1]'\n");
-    BOOST_CHECK_EQUAL(HelpExampleRpcNamed("test", {{"name", arr_value}}), "> curl --user myusername --data-binary '{\"jsonrpc\": \"2.0\", \"id\": \"curltest\", \"method\": \"test\", \"params\": {\"name\":[\"bar\",false,1]}}' -H 'content-type: application/json;' http://127.0.0.1:8332/\n");
+    BOOST_CHECK_EQUAL(HelpExampleRpcNamed("test", {{"name", arr_value}}), "> curl --user myusername --data-binary '{\"jsonrpc\": \"2.0\", \"id\": \"curltest\", \"method\": \"test\", \"params\": {\"name\":[\"bar\",false,1]}}' -H 'content-type: application/json' http://127.0.0.1:8332/\n");
 
     // test types don't matter for shell
     BOOST_CHECK_EQUAL(HelpExampleCliNamed("foo", {{"arg", true}}), HelpExampleCliNamed("foo", {{"arg", "true"}}));
diff --git a/test/functional/interface_rpc.py b/test/functional/interface_rpc.py
index b08ca42796..6c1855c400 100755
--- a/test/functional/interface_rpc.py
+++ b/test/functional/interface_rpc.py
@@ -14,7 +14,6 @@ from typing import Optional
 import subprocess
 
 
-RPC_INVALID_ADDRESS_OR_KEY = -5
 RPC_INVALID_PARAMETER      = -8
 RPC_METHOD_NOT_FOUND       = -32601
 RPC_INVALID_REQUEST        = -32600
diff --git a/test/functional/test_framework/authproxy.py b/test/functional/test_framework/authproxy.py
index 7edf9f3679..a357ae4d34 100644
--- a/test/functional/test_framework/authproxy.py
+++ b/test/functional/test_framework/authproxy.py
@@ -26,7 +26,7 @@ ServiceProxy class:
 
 - HTTP connections persist for the life of the AuthServiceProxy object
   (if server supports HTTP/1.1)
-- sends protocol 'version', per JSON-RPC 1.1
+- sends "jsonrpc":"2.0", per JSON-RPC 2.0
 - sends proper, incrementing 'id'
 - sends Basic HTTP authentication headers
 - parses all JSON numbers that look like floats as Decimal
@@ -117,7 +117,7 @@ class AuthServiceProxy():
             params = dict(args=args, **argsn)
         else:
             params = args or argsn
-        return {'version': '1.1',
+        return {'jsonrpc': '2.0',
                 'method': self._service_name,
                 'params': params,
                 'id': AuthServiceProxy.__id_count}
@@ -125,15 +125,28 @@ class AuthServiceProxy():
     def __call__(self, *args, **argsn):
         postdata = json.dumps(self.get_request(*args, **argsn), default=serialization_fallback, ensure_ascii=self.ensure_ascii)
         response, status = self._request('POST', self.__url.path, postdata.encode('utf-8'))
-        if response['error'] is not None:
-            raise JSONRPCException(response['error'], status)
-        elif 'result' not in response:
-            raise JSONRPCException({
-                'code': -343, 'message': 'missing JSON-RPC result'}, status)
-        elif status != HTTPStatus.OK:
-            raise JSONRPCException({
-                'code': -342, 'message': 'non-200 HTTP status code but no JSON-RPC error'}, status)
+        # For backwards compatibility tests, accept JSON RPC 1.1 responses
+        if 'jsonrpc' not in response:
+            if response['error'] is not None:
+                raise JSONRPCException(response['error'], status)
+            elif 'result' not in response:
+                raise JSONRPCException({
+                    'code': -343, 'message': 'missing JSON-RPC result'}, status)
+            elif status != HTTPStatus.OK:
+                raise JSONRPCException({
+                    'code': -342, 'message': 'non-200 HTTP status code but no JSON-RPC error'}, status)
+            else:
+                return response['result']
         else:
+            assert response['jsonrpc'] == '2.0'
+            if status != HTTPStatus.OK:
+                raise JSONRPCException({
+                    'code': -342, 'message': 'non-200 HTTP status code'}, status)
+            if 'error' in response:
+                raise JSONRPCException(response['error'], status)
+            elif 'result' not in response:
+                raise JSONRPCException({
+                    'code': -343, 'message': 'missing JSON-RPC 2.0 result and error'}, status)
             return response['result']
 
     def batch(self, rpc_call_list):
@@ -142,7 +155,7 @@ class AuthServiceProxy():
         response, status = self._request('POST', self.__url.path, postdata.encode('utf-8'))
         if status != HTTPStatus.OK:
             raise JSONRPCException({
-                'code': -342, 'message': 'non-200 HTTP status code but no JSON-RPC error'}, status)
+                'code': -342, 'message': 'non-200 HTTP status code'}, status)
         return response
 
     def _get_response(self):