Decorate doesn't work with a dependency group

[ermanimer]

Hello,

First of all thank you for the great work!

I have a question: The Decorate function doesn't work with a dependency group while it works with a dependency. Am I missing something?

Here is the repro commit: https://github.com/ermanimer/common/tree/1bd9b2f20c5bb7eda17bf71b4305c7c090916fc3

It works with a dependency:

// Package samplemiddleware ...
package samplemiddleware

import (
	"log/slog"
	"net/http"

	"github.com/ermanimer/common/httpserver"

	"go.uber.org/fx"
)

// Module ...
var Module = fx.Module(
	"sample_middleware",
	fx.Provide(
		New,
	),
	fx.Decorate(
		wrapLogger,
	),
)

// Parameter ...
type Parameter struct {
	fx.In

	Logger *slog.Logger
}

// Result ...
type Result struct {
	fx.Out

	Middleware httpserver.Middleware `name:"sample_middleware"`
}

type middleware struct {
	logger *slog.Logger
	next   httpserver.Route
}

// New ...
func New(parameter Parameter) Result {
	var sampleMiddleware httpserver.Middleware = func(next httpserver.Route) httpserver.Route {
		return &middleware{
			logger: parameter.Logger,
			next:   next,
		}
	}

	result := Result{
		Middleware: sampleMiddleware,
	}

	return result
}

func wrapLogger(logger *slog.Logger) *slog.Logger {
	return logger.With("module", "sample_middleware")
}

func (m *middleware) Method() string {
	return m.next.Method()
}

func (m *middleware) Path() string {
	return m.next.Path()
}

func (m *middleware) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	m.logger.Info("sample middleware")
	m.next.ServeHTTP(w, r)
}

But it doesn't work with a dependency group:

// Package sampleroute ...
package sampleroute

import (
	"log/slog"
	"net/http"

	"github.com/ermanimer/common/httpserver"

	"go.uber.org/fx"
)

// Module ...
var Module = fx.Module(
	"sample_route",
	fx.Provide(
		New,
	),
	fx.Decorate(
		wrapLogger,
	),
)

// Parameter ...
type Parameter struct {
	fx.In

	Logger           *slog.Logger
	SampleMiddleware httpserver.Middleware `name:"sample_middleware"`
}

// Result ...
type Result struct {
	fx.Out

	Route httpserver.Route `group:"routes"`
}

type route struct {
	logger *slog.Logger
}

// New ...
func New(parameter Parameter) Result {
	var sampleRoute httpserver.Route = &route{
		logger: parameter.Logger,
	}

	sampleRoute = parameter.SampleMiddleware(sampleRoute)

	result := Result{
		Route: sampleRoute,
	}

	return result
}

func wrapLogger(logger *slog.Logger) *slog.Logger {
	return logger.With("module", "sample_middleware")
}

func (r *route) Method() string {
	return http.MethodGet
}

func (r *route) Path() string {
	return "/sample"
}

func (r *route) ServeHTTP(w http.ResponseWriter, _ *http.Request) {
	r.logger.Info("sample route")
	w.Header().Set("Content-Type", "text/plain")
	w.WriteHeader(http.StatusOK)
	_, err := w.Write([]byte("sample route\n"))
	if err != nil {
		r.logger.Error("failed to write response", "error", err)
	}
}

func (r *route) Logger() *slog.Logger {
	return r.logger
}

Any help is appreciated.

[JacobOaks]

Hi there, thanks for bringing this up. This issue has been reported before (#1104). It's actually an issue in Dig - a dependency of Fx - that has been fixed (uber-go/dig#393), we just need to upgrade Fx to use the latest Dig version - I have a PR out for that now (#1138). One that merges, this issue should be solved.

[ermanimer]

Thank you 🙂