rpc: Deprecate rpcserialversion=0

Author: ajtowns

doc/release-notes-28448.md

@@ -0,0 +1,6 @@
+RPC
+---
+
+- Setting `-rpcserialversion=0` is deprecated and will be removed in
+  a future release. It can currently still be used by also adding
+  the `-deprecatedrpc=serialversion` option. (#28448)

src/init.cpp

@@ -618,7 +618,7 @@ void SetupServerArgs(ArgsManager& argsman)
     argsman.AddArg("-rpccookiefile=<loc>", "Location of the auth cookie. Relative paths will be prefixed by a net-specific datadir location. (default: data dir)", ArgsManager::ALLOW_ANY, OptionsCategory::RPC);
     argsman.AddArg("-rpcpassword=<pw>", "Password for JSON-RPC connections", ArgsManager::ALLOW_ANY | ArgsManager::SENSITIVE, OptionsCategory::RPC);
     argsman.AddArg("-rpcport=<port>", strprintf("Listen for JSON-RPC connections on <port> (default: %u, testnet: %u, signet: %u, regtest: %u)", defaultBaseParams->RPCPort(), testnetBaseParams->RPCPort(), signetBaseParams->RPCPort(), regtestBaseParams->RPCPort()), ArgsManager::ALLOW_ANY | ArgsManager::NETWORK_ONLY, OptionsCategory::RPC);
-    argsman.AddArg("-rpcserialversion", strprintf("Sets the serialization of raw transaction or block hex returned in non-verbose mode, non-segwit(0) or segwit(1) (default: %d)", DEFAULT_RPC_SERIALIZE_VERSION), ArgsManager::ALLOW_ANY, OptionsCategory::RPC);
+    argsman.AddArg("-rpcserialversion", strprintf("Sets the serialization of raw transaction or block hex returned in non-verbose mode, non-segwit(0) (DEPRECATED) or segwit(1) (default: %d)", DEFAULT_RPC_SERIALIZE_VERSION), ArgsManager::ALLOW_ANY, OptionsCategory::RPC);
     argsman.AddArg("-rpcservertimeout=<n>", strprintf("Timeout during HTTP requests (default: %d)", DEFAULT_HTTP_SERVER_TIMEOUT), ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::RPC);
     argsman.AddArg("-rpcthreads=<n>", strprintf("Set the number of threads to service RPC calls (default: %d)", DEFAULT_HTTP_THREADS), ArgsManager::ALLOW_ANY, OptionsCategory::RPC);
     argsman.AddArg("-rpcuser=<user>", "Username for JSON-RPC connections", ArgsManager::ALLOW_ANY | ArgsManager::SENSITIVE, OptionsCategory::RPC);
@@ -988,6 +988,10 @@ bool AppInitParameterInteraction(const ArgsManager& args)
     if (args.GetIntArg("-rpcserialversion", DEFAULT_RPC_SERIALIZE_VERSION) > 1)
         return InitError(Untranslated("Unknown rpcserialversion requested."));
 
+    if (args.GetIntArg("-rpcserialversion", DEFAULT_RPC_SERIALIZE_VERSION) == 0 && !IsDeprecatedRPCEnabled("serialversion")) {
+        return InitError(Untranslated("-rpcserialversion=0 is deprecated and will be removed in the future. Specify -deprecatedrpc=serialversion to allow anyway."));
+    }
+
     // Also report errors from parsing before daemonization
     {
         kernel::Notifications notifications{};

test/functional/feature_segwit.py

@@ -89,6 +89,7 @@ def set_test_params(self):
             [
                 "-acceptnonstdtxn=1",
                 "-rpcserialversion=0",
+                "-deprecatedrpc=serialversion",
                 "-testactivationheight=segwit@165",
                 "-addresstype=legacy",
             ],