feat(core/handlers): improve handlers registration DevX (#22007)

core/appmodule/v2/handlers.go

@@ -10,19 +10,19 @@ import (
 type (
 	// PreMsgHandler is a handler that is executed before Handler. If it errors the execution reverts.
 	PreMsgHandler = func(ctx context.Context, msg transaction.Msg) error
-	// Handler handles the state transition of the provided message.
-	Handler = func(ctx context.Context, msg transaction.Msg) (msgResp transaction.Msg, err error)
+	// HandlerFunc handles the state transition of the provided message.
+	HandlerFunc = func(ctx context.Context, msg transaction.Msg) (msgResp transaction.Msg, err error)
 	// PostMsgHandler runs after Handler, only if Handler does not error. If PostMsgHandler errors
 	// then the execution is reverted.
 	PostMsgHandler = func(ctx context.Context, msg, msgResp transaction.Msg) error
 )
 
 // PreMsgRouter is a router that allows you to register PreMsgHandlers for specific message types.
 type PreMsgRouter interface {
-	// RegisterPreHandler will register a specific message handler hooking into the message with
+	// RegisterPreMsgHandler will register a specific message handler hooking into the message with
 	// the provided name.
 	RegisterPreMsgHandler(msgName string, handler PreMsgHandler)
-	// RegisterGlobalPreHandler will register a global message handler hooking into any message
+	// RegisterGlobalPreMsgHandler will register a global message handler hooking into any message
 	// being executed.
 	RegisterGlobalPreMsgHandler(handler PreMsgHandler)
 }
@@ -64,10 +64,10 @@ func RegisterMsgPreHandler[Req transaction.Msg](
 
 // PostMsgRouter is a router that allows you to register PostMsgHandlers for specific message types.
 type PostMsgRouter interface {
-	// RegisterPostHandler will register a specific message handler hooking after the execution of message with
+	// RegisterPostMsgHandler will register a specific message handler hooking after the execution of message with
 	// the provided name.
 	RegisterPostMsgHandler(msgName string, handler PostMsgHandler)
-	// RegisterGlobalPostHandler will register a global message handler hooking after the execution of any message.
+	// RegisterGlobalPostMsgHandler will register a global message handler hooking after the execution of any message.
 	RegisterGlobalPostMsgHandler(handler PostMsgHandler)
 }
 
@@ -76,7 +76,7 @@ type HasPostMsgHandlers interface {
 	RegisterPostMsgHandlers(router PostMsgRouter)
 }
 
-// RegisterPostHandler is a helper function that modules can use to not lose type safety when registering handlers to the
+// RegisterPostMsgHandler is a helper function that modules can use to not lose type safety when registering handlers to the
 // PostMsgRouter. Example usage:
 // ```go
 //
@@ -110,9 +110,20 @@ func RegisterPostMsgHandler[Req, Resp transaction.Msg](
 	router.RegisterPostMsgHandler(msgName, untypedHandler)
 }
 
+// Handler defines a handler descriptor.
+type Handler struct {
+	// Func defines the actual handler, the function that runs a request and returns a response.
+	// Can be query handler or msg handler.
+	Func HandlerFunc
+	// MakeMsg instantiates the type of the request, can be used in decoding contexts.
+	MakeMsg func() transaction.Msg
+	// MakeMsgResp instantiates a new response, can be used in decoding contexts.
+	MakeMsgResp func() transaction.Msg
+}
+
 // MsgRouter is a router that allows you to register Handlers for specific message types.
 type MsgRouter = interface {
-	RegisterHandler(msgName string, handler Handler) error
+	RegisterHandler(handler Handler)
 }
 
 // HasMsgHandlers is an interface that modules must implement if they want to register Handlers.
@@ -142,27 +153,34 @@ type HasQueryHandlers interface {
 //
 //	func (m Module) RegisterMsgHandlers(router appmodule.MsgRouter) {
 //		handlers := keeper.NewHandlers(m.keeper)
-//	    err := appmodule.RegisterHandler(router, gogoproto.MessageName(types.MsgMint{}), handlers.MsgMint)
+//	    err := appmodule.RegisterHandler(router, handlers.MsgMint)
 //	}
 //
 //	func (m Module) RegisterQueryHandlers(router appmodule.QueryRouter) {
 //		handlers := keeper.NewHandlers(m.keeper)
-//	    err := appmodule.RegisterHandler(router, gogoproto.MessageName(types.QueryBalanceRequest{}), handlers.QueryBalance)
+//	    err := appmodule.RegisterHandler(router, handlers.QueryBalance)
 //	}
 //
 // ```
-func RegisterHandler[Req, Resp transaction.Msg](
+func RegisterMsgHandler[Req, Resp any, PReq transaction.GenericMsg[Req], PResp transaction.GenericMsg[Resp]](
 	router MsgRouter,
-	msgName string,
-	handler func(ctx context.Context, msg Req) (msgResp Resp, err error),
-) error {
+	handler func(ctx context.Context, msg PReq) (msgResp PResp, err error),
+) {
 	untypedHandler := func(ctx context.Context, m transaction.Msg) (transaction.Msg, error) {
-		typed, ok := m.(Req)
+		typed, ok := m.(PReq)
 		if !ok {
 			return nil, fmt.Errorf("unexpected type %T, wanted: %T", m, *new(Req))
 		}
 		return handler(ctx, typed)
 	}
 
-	return router.RegisterHandler(msgName, untypedHandler)
+	router.RegisterHandler(Handler{
+		Func: untypedHandler,
+		MakeMsg: func() transaction.Msg {
+			return PReq(new(Req))
+		},
+		MakeMsgResp: func() transaction.Msg {
+			return PResp(new(Resp))
+		},
+	})
 }

core/transaction/transaction.go

@@ -10,6 +10,14 @@ type (
 	Identity = []byte
 )
 
+// GenericMsg defines a generic version of a Msg.
+// The GenericMsg refers to the non pointer version of Msg,
+// and is required to allow its instantiations in generic contexts.
+type GenericMsg[T any] interface {
+	*T
+	Msg
+}
+
 // Codec defines the TX codec, which converts a TX from bytes to its concrete representation.
 type Codec[T Tx] interface {
 	// Decode decodes the tx bytes into a DecodedTx, containing

simapp/v2/go.mod

@@ -5,7 +5,7 @@ go 1.23.1
 require (
 	cosmossdk.io/api v0.7.6
 	cosmossdk.io/client/v2 v2.0.0-00010101000000-000000000000
-	cosmossdk.io/core v1.0.0-alpha.3
+	cosmossdk.io/core v1.0.0-alpha.3.0.20241001182821-3f9c9a087760
 	cosmossdk.io/depinject v1.0.0
 	cosmossdk.io/log v1.4.1
 	cosmossdk.io/math v1.3.0
@@ -291,7 +291,6 @@ replace (
 // server v2 integration
 replace (
 	cosmossdk.io/api => ../../api
-	cosmossdk.io/core => ../../core
 	cosmossdk.io/runtime/v2 => ../../runtime/v2
 	cosmossdk.io/server/v2 => ../../server/v2
 	cosmossdk.io/server/v2/appmanager => ../../server/v2/appmanager

simapp/v2/go.sum

@@ -192,6 +192,8 @@ cloud.google.com/go/webrisk v1.4.0/go.mod h1:Hn8X6Zr+ziE2aNd8SliSDWpEnSS1u4R9+xX
 cloud.google.com/go/webrisk v1.5.0/go.mod h1:iPG6fr52Tv7sGk0H6qUFzmL3HHZev1htXuWDEEsqMTg=
 cloud.google.com/go/workflows v1.6.0/go.mod h1:6t9F5h/unJz41YqfBmqSASJSXccBLtD1Vwf+KmJENM0=
 cloud.google.com/go/workflows v1.7.0/go.mod h1:JhSrZuVZWuiDfKEFxU0/F1PQjmpnpcoISEXH2bcHC3M=
+cosmossdk.io/core v1.0.0-alpha.3.0.20241001182821-3f9c9a087760 h1:jyldjo99XdhT94cIyoSVBT2hxNoI4X/1pEUh4+659e0=
+cosmossdk.io/core v1.0.0-alpha.3.0.20241001182821-3f9c9a087760/go.mod h1:3u9cWq1FAVtiiCrDPpo4LhR+9V6k/ycSG4/Y/tREWCY=
 cosmossdk.io/core/testing v0.0.0-20240923163230-04da382a9f29 h1:NxxUo0GMJUbIuVg0R70e3cbn9eFTEuMr7ev1AFvypdY=
 cosmossdk.io/core/testing v0.0.0-20240923163230-04da382a9f29/go.mod h1:8s2tPeJtSiQuoyPmr2Ag7meikonISO4Fv4MoO8+ORrs=
 cosmossdk.io/depinject v1.0.0 h1:dQaTu6+O6askNXO06+jyeUAnF2/ssKwrrszP9t5q050=