http: Fix subroutes, ensure that next handlers can still be called

modules/caddyhttp/caddyhttp.go

@@ -172,7 +172,7 @@ func (app *App) Provision(ctx caddy.Context) error {
 			}
 			// pre-compile the handler chain, and be sure to wrap it in our
 			// route handler so that important security checks are done, etc.
-			primaryRoute = srv.Routes.Compile()
+			primaryRoute = srv.Routes.Compile(emptyHandler)
 		}
 		srv.primaryHandlerChain = srv.wrapPrimaryRoute(primaryRoute)
 
@@ -181,7 +181,7 @@ func (app *App) Provision(ctx caddy.Context) error {
 			if err != nil {
 				return fmt.Errorf("server %s: setting up server error handling routes: %v", srvName, err)
 			}
-			srv.errorHandlerChain = srv.Errors.Routes.Compile()
+			srv.errorHandlerChain = srv.Errors.Routes.Compile(emptyHandler)
 		}
 	}
 
@@ -546,7 +546,7 @@ func (app *App) automaticHTTPS() error {
 				tlsApp:              tlsApp, // required to solve HTTP challenge
 				logger:              app.logger.Named("log"),
 				errorLogger:         app.logger.Named("log.error"),
-				primaryHandlerChain: redirRoutes.Compile(),
+				primaryHandlerChain: redirRoutes.Compile(emptyHandler),
 			}
 		}
 	}

modules/caddyhttp/routes.go

@@ -147,12 +147,12 @@ func (routes RouteList) Provision(ctx caddy.Context) error {
 // Compile prepares a middleware chain from the route list.
 // This should only be done once: after all the routes have
 // been provisioned, and before serving requests.
-func (routes RouteList) Compile() Handler {
+func (routes RouteList) Compile(next Handler) Handler {
 	var mid []Middleware
 	for _, route := range routes {
 		mid = append(mid, wrapRoute(route))
 	}
-	stack := emptyHandler
+	stack := next
 	for i := len(mid) - 1; i >= 0; i-- {
 		stack = mid[i](stack)
 	}
@@ -167,6 +167,7 @@ func (routes RouteList) Compile() Handler {
 func wrapRoute(route Route) Middleware {
 	return func(next Handler) Handler {
 		return HandlerFunc(func(rw http.ResponseWriter, req *http.Request) error {
+			// TODO: Update this comment, it seems we've moved the copy into the handler?
 			// copy the next handler (it's an interface, so it's just
 			// a very lightweight copy of a pointer); this is important
 			// because this is a closure to the func below, which

modules/caddyhttp/subroute.go

@@ -69,12 +69,12 @@ func (sr *Subroute) Provision(ctx caddy.Context) error {
 	return nil
 }
 
-func (sr *Subroute) ServeHTTP(w http.ResponseWriter, r *http.Request, _ Handler) error {
-	subroute := sr.Routes.Compile()
+func (sr *Subroute) ServeHTTP(w http.ResponseWriter, r *http.Request, next Handler) error {
+	subroute := sr.Routes.Compile(next)
 	err := subroute.ServeHTTP(w, r)
 	if err != nil && sr.Errors != nil {
 		r = sr.Errors.WithError(r, err)
-		errRoute := sr.Errors.Routes.Compile()
+		errRoute := sr.Errors.Routes.Compile(next)
 		return errRoute.ServeHTTP(w, r)
 	}
 	return err