[Net] Single `rpc` annotation. "sync" no longer part of mode.

- Move the "sync" property for RPCs to RPCConfig.

- Unify GDScript annotations into a single one:
  - `@rpc(master)` # default
  - `@rpc(puppet)`
  - `@rpc(any)` # former `@remote`

- Implement three additional `@rpc` options:
  - The second parameter is the "sync" option (which also calls the
    function locally when RPCing). One of "sync", "nosync".
  - The third parameter is the transfer mode (reliable, unreliable,
    ordered).
  - The third parameter is the channel (unused for now).

14 files changed, 66 insertions, 70 deletions

diff --git a/modules/gdscript/gdscript.cpp b/modules/gdscript/gdscript.cpp
index 8b12b1eae4..d0b7722847 100644
--- a/modules/gdscript/gdscript.cpp
+++ b/modules/gdscript/gdscript.cpp
@@ -1165,15 +1165,11 @@ void GDScript::_init_rpc_methods_properties() {
 	while (cscript) {
 		// RPC Methods
 		for (Map<StringName, GDScriptFunction *>::Element *E = cscript->member_functions.front(); E; E = E->next()) {
-			if (E->get()->get_rpc_mode() != MultiplayerAPI::RPC_MODE_DISABLED) {
-				MultiplayerAPI::RPCConfig nd;
-				nd.name = E->key();
-				nd.rpc_mode = E->get()->get_rpc_mode();
-				// TODO
-				nd.transfer_mode = MultiplayerPeer::TRANSFER_MODE_RELIABLE;
-				nd.channel = 0;
-				if (-1 == rpc_functions.find(nd)) {
-					rpc_functions.push_back(nd);
+			MultiplayerAPI::RPCConfig config = E->get()->get_rpc_config();
+			if (config.rpc_mode != MultiplayerAPI::RPC_MODE_DISABLED) {
+				config.name = E->get()->get_name();
+				if (rpc_functions.find(config) == -1) {
+					rpc_functions.push_back(config);
 				}
 			}
 		}
diff --git a/modules/gdscript/gdscript.h b/modules/gdscript/gdscript.h
index 078b7a2fd0..24809ad5fd 100644
--- a/modules/gdscript/gdscript.h
+++ b/modules/gdscript/gdscript.h
@@ -64,7 +64,6 @@ class GDScript : public Script {
 		int index = 0;
 		StringName setter;
 		StringName getter;
-		MultiplayerAPI::RPCMode rpc_mode;
 		GDScriptDataType data_type;
 	};
 
diff --git a/modules/gdscript/gdscript_byte_codegen.cpp b/modules/gdscript/gdscript_byte_codegen.cpp
index 5a297cc50a..9ff5a342ec 100644
--- a/modules/gdscript/gdscript_byte_codegen.cpp
+++ b/modules/gdscript/gdscript_byte_codegen.cpp
@@ -155,7 +155,7 @@ void GDScriptByteCodeGenerator::end_parameters() {
 	function->default_arguments.reverse();
 }
 
-void GDScriptByteCodeGenerator::write_start(GDScript *p_script, const StringName &p_function_name, bool p_static, MultiplayerAPI::RPCMode p_rpc_mode, const GDScriptDataType &p_return_type) {
+void GDScriptByteCodeGenerator::write_start(GDScript *p_script, const StringName &p_function_name, bool p_static, MultiplayerAPI::RPCConfig p_rpc_config, const GDScriptDataType &p_return_type) {
 	function = memnew(GDScriptFunction);
 	debug_stack = EngineDebugger::is_active();
 
@@ -170,7 +170,7 @@ void GDScriptByteCodeGenerator::write_start(GDScript *p_script, const StringName
 
 	function->_static = p_static;
 	function->return_type = p_return_type;
-	function->rpc_mode = p_rpc_mode;
+	function->rpc_config = p_rpc_config;
 	function->_argument_count = 0;
 }
 
diff --git a/modules/gdscript/gdscript_byte_codegen.h b/modules/gdscript/gdscript_byte_codegen.h
index b1f3cd5fb3..3d6fb291ad 100644
--- a/modules/gdscript/gdscript_byte_codegen.h
+++ b/modules/gdscript/gdscript_byte_codegen.h
@@ -419,7 +419,7 @@ public:
 	virtual void start_block() override;
 	virtual void end_block() override;
 
-	virtual void write_start(GDScript *p_script, const StringName &p_function_name, bool p_static, MultiplayerAPI::RPCMode p_rpc_mode, const GDScriptDataType &p_return_type) override;
+	virtual void write_start(GDScript *p_script, const StringName &p_function_name, bool p_static, MultiplayerAPI::RPCConfig p_rpc_config, const GDScriptDataType &p_return_type) override;
 	virtual GDScriptFunction *write_end() override;
 
 #ifdef DEBUG_ENABLED
diff --git a/modules/gdscript/gdscript_codegen.h b/modules/gdscript/gdscript_codegen.h
index cac6544f03..ecc86c37f3 100644
--- a/modules/gdscript/gdscript_codegen.h
+++ b/modules/gdscript/gdscript_codegen.h
@@ -80,7 +80,7 @@ public:
 	virtual void start_block() = 0;
 	virtual void end_block() = 0;
 
-	virtual void write_start(GDScript *p_script, const StringName &p_function_name, bool p_static, MultiplayerAPI::RPCMode p_rpc_mode, const GDScriptDataType &p_return_type) = 0;
+	virtual void write_start(GDScript *p_script, const StringName &p_function_name, bool p_static, MultiplayerAPI::RPCConfig p_rpc_config, const GDScriptDataType &p_return_type) = 0;
 	virtual GDScriptFunction *write_end() = 0;
 
 #ifdef DEBUG_ENABLED
diff --git a/modules/gdscript/gdscript_compiler.cpp b/modules/gdscript/gdscript_compiler.cpp
index 7fa8e9c067..fbe791a109 100644
--- a/modules/gdscript/gdscript_compiler.cpp
+++ b/modules/gdscript/gdscript_compiler.cpp
@@ -1859,7 +1859,7 @@ GDScriptFunction *GDScriptCompiler::_parse_function(Error &r_error, GDScript *p_
 
 	StringName func_name;
 	bool is_static = false;
-	MultiplayerAPI::RPCMode rpc_mode = MultiplayerAPI::RPC_MODE_DISABLED;
+	MultiplayerAPI::RPCConfig rpc_config;
 	GDScriptDataType return_type;
 	return_type.has_type = true;
 	return_type.kind = GDScriptDataType::BUILTIN;
@@ -1872,7 +1872,7 @@ GDScriptFunction *GDScriptCompiler::_parse_function(Error &r_error, GDScript *p_
 			func_name = "<anonymous lambda>";
 		}
 		is_static = p_func->is_static;
-		rpc_mode = p_func->rpc_mode;
+		rpc_config = p_func->rpc_config;
 		return_type = _gdtype_from_datatype(p_func->get_datatype(), p_script);
 	} else {
 		if (p_for_ready) {
@@ -1883,7 +1883,7 @@ GDScriptFunction *GDScriptCompiler::_parse_function(Error &r_error, GDScript *p_
 	}
 
 	codegen.function_name = func_name;
-	codegen.generator->write_start(p_script, func_name, is_static, rpc_mode, return_type);
+	codegen.generator->write_start(p_script, func_name, is_static, rpc_config, return_type);
 
 	int optional_parameters = 0;
 
@@ -2088,7 +2088,7 @@ Error GDScriptCompiler::_parse_setter_getter(GDScript *p_script, const GDScriptP
 		return_type = _gdtype_from_datatype(p_variable->get_datatype(), p_script);
 	}
 
-	codegen.generator->write_start(p_script, func_name, false, p_variable->rpc_mode, return_type);
+	codegen.generator->write_start(p_script, func_name, false, MultiplayerAPI::RPCConfig(), return_type);
 
 	if (p_is_setter) {
 		uint32_t par_addr = codegen.generator->add_parameter(p_variable->setter_parameter->name, false, _gdtype_from_datatype(p_variable->get_datatype()));
@@ -2268,7 +2268,6 @@ Error GDScriptCompiler::_parse_class_level(GDScript *p_script, const GDScriptPar
 						}
 						break;
 				}
-				minfo.rpc_mode = variable->rpc_mode;
 				minfo.data_type = _gdtype_from_datatype(variable->get_datatype(), p_script);
 
 				PropertyInfo prop_info = minfo.data_type;
diff --git a/modules/gdscript/gdscript_function.h b/modules/gdscript/gdscript_function.h
index 553c2ecc01..9e5ef0f632 100644
--- a/modules/gdscript/gdscript_function.h
+++ b/modules/gdscript/gdscript_function.h
@@ -472,7 +472,7 @@ private:
 
 	int _initial_line = 0;
 	bool _static = false;
-	MultiplayerAPI::RPCMode rpc_mode = MultiplayerAPI::RPC_MODE_DISABLED;
+	MultiplayerAPI::RPCConfig rpc_config;
 
 	GDScript *_script = nullptr;
 
@@ -592,7 +592,7 @@ public:
 	void disassemble(const Vector<String> &p_code_lines) const;
 #endif
 
-	_FORCE_INLINE_ MultiplayerAPI::RPCMode get_rpc_mode() const { return rpc_mode; }
+	_FORCE_INLINE_ MultiplayerAPI::RPCConfig get_rpc_config() const { return rpc_config; }
 	GDScriptFunction();
 	~GDScriptFunction();
 };
diff --git a/modules/gdscript/gdscript_parser.cpp b/modules/gdscript/gdscript_parser.cpp
index 1a22820c63..df36afc0f0 100644
--- a/modules/gdscript/gdscript_parser.cpp
+++ b/modules/gdscript/gdscript_parser.cpp
@@ -168,12 +168,7 @@ GDScriptParser::GDScriptParser() {
 	register_annotation(MethodInfo("@export_flags_3d_physics"), AnnotationInfo::VARIABLE, &GDScriptParser::export_annotations<PROPERTY_HINT_LAYERS_3D_PHYSICS, Variant::INT>);
 	register_annotation(MethodInfo("@export_flags_3d_navigation"), AnnotationInfo::VARIABLE, &GDScriptParser::export_annotations<PROPERTY_HINT_LAYERS_3D_NAVIGATION, Variant::INT>);
 	// Networking.
-	register_annotation(MethodInfo("@remote"), AnnotationInfo::VARIABLE | AnnotationInfo::FUNCTION, &GDScriptParser::network_annotations<MultiplayerAPI::RPC_MODE_REMOTE>);
-	register_annotation(MethodInfo("@master"), AnnotationInfo::VARIABLE | AnnotationInfo::FUNCTION, &GDScriptParser::network_annotations<MultiplayerAPI::RPC_MODE_MASTER>);
-	register_annotation(MethodInfo("@puppet"), AnnotationInfo::VARIABLE | AnnotationInfo::FUNCTION, &GDScriptParser::network_annotations<MultiplayerAPI::RPC_MODE_PUPPET>);
-	register_annotation(MethodInfo("@remotesync"), AnnotationInfo::VARIABLE | AnnotationInfo::FUNCTION, &GDScriptParser::network_annotations<MultiplayerAPI::RPC_MODE_REMOTESYNC>);
-	register_annotation(MethodInfo("@mastersync"), AnnotationInfo::VARIABLE | AnnotationInfo::FUNCTION, &GDScriptParser::network_annotations<MultiplayerAPI::RPC_MODE_MASTERSYNC>);
-	register_annotation(MethodInfo("@puppetsync"), AnnotationInfo::VARIABLE | AnnotationInfo::FUNCTION, &GDScriptParser::network_annotations<MultiplayerAPI::RPC_MODE_PUPPETSYNC>);
+	register_annotation(MethodInfo("@rpc", { Variant::STRING, "mode" }, { Variant::STRING, "sync" }, { Variant::STRING, "transfer_mode" }, { Variant::INT, "transfer_channel" }), AnnotationInfo::FUNCTION, &GDScriptParser::network_annotations<MultiplayerAPI::RPC_MODE_MASTER>, 4, true);
 	// TODO: Warning annotations.
 }
 
@@ -3430,27 +3425,60 @@ template <MultiplayerAPI::RPCMode t_mode>
 bool GDScriptParser::network_annotations(const AnnotationNode *p_annotation, Node *p_node) {
 	ERR_FAIL_COND_V_MSG(p_node->type != Node::VARIABLE && p_node->type != Node::FUNCTION, false, vformat(R"("%s" annotation can only be applied to variables and functions.)", p_annotation->name));
 
-	switch (p_node->type) {
-		case Node::VARIABLE: {
-			VariableNode *variable = static_cast<VariableNode *>(p_node);
-			if (variable->rpc_mode != MultiplayerAPI::RPC_MODE_DISABLED) {
-				push_error(R"(RPC annotations can only be used once per variable.)", p_annotation);
+	MultiplayerAPI::RPCConfig rpc_config;
+	rpc_config.rpc_mode = t_mode;
+	for (int i = 0; i < p_annotation->resolved_arguments.size(); i++) {
+		if (i == 0) {
+			String mode = p_annotation->resolved_arguments[i].operator String();
+			if (mode == "any") {
+				rpc_config.rpc_mode = MultiplayerAPI::RPC_MODE_REMOTE;
+			} else if (mode == "master") {
+				rpc_config.rpc_mode = MultiplayerAPI::RPC_MODE_MASTER;
+			} else if (mode == "puppet") {
+				rpc_config.rpc_mode = MultiplayerAPI::RPC_MODE_PUPPET;
+			} else {
+				push_error(R"(Invalid RPC mode. Must be one of: 'any', 'master', or 'puppet')", p_annotation);
+				return false;
 			}
-			variable->rpc_mode = t_mode;
-			break;
+		} else if (i == 1) {
+			String sync = p_annotation->resolved_arguments[i].operator String();
+			if (sync == "sync") {
+				rpc_config.sync = true;
+			} else if (sync == "nosync") {
+				rpc_config.sync = false;
+			} else {
+				push_error(R"(Invalid RPC sync mode. Must be one of: 'sync' or 'nosync')", p_annotation);
+				return false;
+			}
+		} else if (i == 2) {
+			String mode = p_annotation->resolved_arguments[i].operator String();
+			if (mode == "reliable") {
+				rpc_config.transfer_mode = MultiplayerPeer::TRANSFER_MODE_RELIABLE;
+			} else if (mode == "unreliable") {
+				rpc_config.transfer_mode = MultiplayerPeer::TRANSFER_MODE_UNRELIABLE;
+			} else if (mode == "ordered") {
+				rpc_config.transfer_mode = MultiplayerPeer::TRANSFER_MODE_UNRELIABLE_ORDERED;
+			} else {
+				push_error(R"(Invalid RPC transfer mode. Must be one of: 'reliable', 'unreliable', 'ordered')", p_annotation);
+				return false;
+			}
+		} else if (i == 3) {
+			rpc_config.channel = p_annotation->resolved_arguments[i].operator int();
 		}
+	}
+	switch (p_node->type) {
 		case Node::FUNCTION: {
 			FunctionNode *function = static_cast<FunctionNode *>(p_node);
-			if (function->rpc_mode != MultiplayerAPI::RPC_MODE_DISABLED) {
+			if (function->rpc_config.rpc_mode != MultiplayerAPI::RPC_MODE_DISABLED) {
 				push_error(R"(RPC annotations can only be used once per function.)", p_annotation);
+				return false;
 			}
-			function->rpc_mode = t_mode;
+			function->rpc_config = rpc_config;
 			break;
 		}
 		default:
 			return false; // Unreachable.
 	}
-
 	return true;
 }
 
diff --git a/modules/gdscript/gdscript_parser.h b/modules/gdscript/gdscript_parser.h
index 9e0b60a407..043d87c705 100644
--- a/modules/gdscript/gdscript_parser.h
+++ b/modules/gdscript/gdscript_parser.h
@@ -729,7 +729,7 @@ public:
 		SuiteNode *body = nullptr;
 		bool is_static = false;
 		bool is_coroutine = false;
-		MultiplayerAPI::RPCMode rpc_mode = MultiplayerAPI::RPC_MODE_DISABLED;
+		MultiplayerAPI::RPCConfig rpc_config;
 		MethodInfo info;
 		LambdaNode *source_lambda = nullptr;
 #ifdef TOOLS_ENABLED
@@ -1117,7 +1117,6 @@ public:
 		bool exported = false;
 		bool onready = false;
 		PropertyInfo export_info;
-		MultiplayerAPI::RPCMode rpc_mode = MultiplayerAPI::RPC_MODE_DISABLED;
 		int assignments = 0;
 		int usages = 0;
 		bool use_conversion_assign = false;
diff --git a/modules/gdscript/language_server/gdscript_extend_parser.cpp b/modules/gdscript/language_server/gdscript_extend_parser.cpp
index f817964a3c..e9a7bf3830 100644
--- a/modules/gdscript/language_server/gdscript_extend_parser.cpp
+++ b/modules/gdscript/language_server/gdscript_extend_parser.cpp
@@ -695,7 +695,9 @@ Dictionary ExtendGDScriptParser::dump_function_api(const GDScriptParser::Functio
 	ERR_FAIL_NULL_V(p_func, func);
 	func["name"] = p_func->identifier->name;
 	func["return_type"] = p_func->get_datatype().to_string();
-	func["rpc_mode"] = p_func->rpc_mode;
+	func["rpc_mode"] = p_func->rpc_config.rpc_mode;
+	func["rpc_transfer_mode"] = p_func->rpc_config.transfer_mode;
+	func["rpc_transfer_channel"] = p_func->rpc_config.channel;
 	Array parameters;
 	for (int i = 0; i < p_func->parameters.size(); i++) {
 		Dictionary arg;
diff --git a/modules/mono/csharp_script.cpp b/modules/mono/csharp_script.cpp
index ff6a47f59b..80675feb3b 100644
--- a/modules/mono/csharp_script.cpp
+++ b/modules/mono/csharp_script.cpp
@@ -3472,15 +3472,6 @@ MultiplayerAPI::RPCMode CSharpScript::_member_get_rpc_mode(IMonoClassMember *p_m
 	if (p_member->has_attribute(CACHED_CLASS(PuppetAttribute))) {
 		return MultiplayerAPI::RPC_MODE_PUPPET;
 	}
-	if (p_member->has_attribute(CACHED_CLASS(RemoteSyncAttribute))) {
-		return MultiplayerAPI::RPC_MODE_REMOTESYNC;
-	}
-	if (p_member->has_attribute(CACHED_CLASS(MasterSyncAttribute))) {
-		return MultiplayerAPI::RPC_MODE_MASTERSYNC;
-	}
-	if (p_member->has_attribute(CACHED_CLASS(PuppetSyncAttribute))) {
-		return MultiplayerAPI::RPC_MODE_PUPPETSYNC;
-	}
 
 	return MultiplayerAPI::RPC_MODE_DISABLED;
 }
diff --git a/modules/mono/glue/GodotSharp/GodotSharp/Core/Attributes/RPCAttributes.cs b/modules/mono/glue/GodotSharp/GodotSharp/Core/Attributes/RPCAttributes.cs
index 8fc430b6bc..6cec8773b2 100644
--- a/modules/mono/glue/GodotSharp/GodotSharp/Core/Attributes/RPCAttributes.cs
+++ b/modules/mono/glue/GodotSharp/GodotSharp/Core/Attributes/RPCAttributes.cs
@@ -2,21 +2,12 @@ using System;
 
 namespace Godot
 {
-    [AttributeUsage(AttributeTargets.Method | AttributeTargets.Field | AttributeTargets.Property)]
+    [AttributeUsage(AttributeTargets.Method)]
     public class RemoteAttribute : Attribute {}
 
-    [AttributeUsage(AttributeTargets.Method | AttributeTargets.Field | AttributeTargets.Property)]
+    [AttributeUsage(AttributeTargets.Method)]
     public class MasterAttribute : Attribute {}
 
-    [AttributeUsage(AttributeTargets.Method | AttributeTargets.Field | AttributeTargets.Property)]
+    [AttributeUsage(AttributeTargets.Method)]
     public class PuppetAttribute : Attribute {}
-
-    [AttributeUsage(AttributeTargets.Method | AttributeTargets.Field | AttributeTargets.Property)]
-    public class RemoteSyncAttribute : Attribute {}
-
-    [AttributeUsage(AttributeTargets.Method | AttributeTargets.Field | AttributeTargets.Property)]
-    public class MasterSyncAttribute : Attribute {}
-
-    [AttributeUsage(AttributeTargets.Method | AttributeTargets.Field | AttributeTargets.Property)]
-    public class PuppetSyncAttribute : Attribute {}
 }
diff --git a/modules/mono/mono_gd/gd_mono_cache.cpp b/modules/mono/mono_gd/gd_mono_cache.cpp
index 341ca88728..0b36796d98 100644
--- a/modules/mono/mono_gd/gd_mono_cache.cpp
+++ b/modules/mono/mono_gd/gd_mono_cache.cpp
@@ -143,9 +143,6 @@ void CachedData::clear_godot_api_cache() {
 	class_RemoteAttribute = nullptr;
 	class_MasterAttribute = nullptr;
 	class_PuppetAttribute = nullptr;
-	class_RemoteSyncAttribute = nullptr;
-	class_MasterSyncAttribute = nullptr;
-	class_PuppetSyncAttribute = nullptr;
 	class_GodotMethodAttribute = nullptr;
 	field_GodotMethodAttribute_methodName = nullptr;
 	class_ScriptPathAttribute = nullptr;
@@ -272,9 +269,6 @@ void update_godot_api_cache() {
 	CACHE_CLASS_AND_CHECK(RemoteAttribute, GODOT_API_CLASS(RemoteAttribute));
 	CACHE_CLASS_AND_CHECK(MasterAttribute, GODOT_API_CLASS(MasterAttribute));
 	CACHE_CLASS_AND_CHECK(PuppetAttribute, GODOT_API_CLASS(PuppetAttribute));
-	CACHE_CLASS_AND_CHECK(RemoteSyncAttribute, GODOT_API_CLASS(RemoteSyncAttribute));
-	CACHE_CLASS_AND_CHECK(MasterSyncAttribute, GODOT_API_CLASS(MasterSyncAttribute));
-	CACHE_CLASS_AND_CHECK(PuppetSyncAttribute, GODOT_API_CLASS(PuppetSyncAttribute));
 	CACHE_CLASS_AND_CHECK(GodotMethodAttribute, GODOT_API_CLASS(GodotMethodAttribute));
 	CACHE_FIELD_AND_CHECK(GodotMethodAttribute, methodName, CACHED_CLASS(GodotMethodAttribute)->get_field("methodName"));
 	CACHE_CLASS_AND_CHECK(ScriptPathAttribute, GODOT_API_CLASS(ScriptPathAttribute));
diff --git a/modules/mono/mono_gd/gd_mono_cache.h b/modules/mono/mono_gd/gd_mono_cache.h
index 3d867060f5..6d49da0af3 100644
--- a/modules/mono/mono_gd/gd_mono_cache.h
+++ b/modules/mono/mono_gd/gd_mono_cache.h
@@ -114,9 +114,6 @@ struct CachedData {
 	GDMonoClass *class_RemoteAttribute;
 	GDMonoClass *class_MasterAttribute;
 	GDMonoClass *class_PuppetAttribute;
-	GDMonoClass *class_RemoteSyncAttribute;
-	GDMonoClass *class_MasterSyncAttribute;
-	GDMonoClass *class_PuppetSyncAttribute;
 	GDMonoClass *class_GodotMethodAttribute;
 	GDMonoField *field_GodotMethodAttribute_methodName;
 	GDMonoClass *class_ScriptPathAttribute;