Fix oauth2 session gob register (#36017)

`gob.Register` must be called before Sessioner

Fix #36016

routers/common/middleware.go

@@ -5,6 +5,7 @@ package common
 
 import (
 	"fmt"
+	"log"
 	"net/http"
 	"strings"
 
@@ -107,7 +108,11 @@ func ForwardedHeadersHandler(limit int, trustedProxies []string) func(h http.Han
 	return proxy.ForwardedHeaders(opt)
 }
 
-func Sessioner() (func(next http.Handler) http.Handler, error) {
+func MustInitSessioner() func(next http.Handler) http.Handler {
+	// TODO: CHI-SESSION-GOB-REGISTER: chi-session has a design problem: it calls gob.Register for "Set"
+	// But if the server restarts, then the first "Get" will fail to decode the previously stored session data because the structs are not registered yet.
+	// So each package should make sure their structs are registered correctly during startup for session storage.
+
 	middleware, err := session.Sessioner(session.Options{
 		Provider:       setting.SessionConfig.Provider,
 		ProviderConfig: setting.SessionConfig.ProviderConfig,
@@ -120,8 +125,7 @@ func Sessioner() (func(next http.Handler) http.Handler, error) {
 		Domain:         setting.SessionConfig.Domain,
 	})
 	if err != nil {
-		return nil, fmt.Errorf("failed to create session middleware: %w", err)
+		log.Fatalf("common.Sessioner failed: %v", err)
 	}
-
-	return middleware, nil
+	return middleware
 }

routers/install/install.go

@@ -55,8 +55,8 @@ func getSupportedDbTypeNames() (dbTypeNames []map[string]string) {
 	return dbTypeNames
 }
 
-// Contexter prepare for rendering installation page
-func Contexter() func(next http.Handler) http.Handler {
+// installContexter prepare for rendering installation page
+func installContexter() func(next http.Handler) http.Handler {
 	rnd := templates.HTMLRenderer()
 	dbTypeNames := getSupportedDbTypeNames()
 	envConfigKeys := setting.CollectEnvConfigKeys()

routers/install/routes.go

@@ -8,7 +8,6 @@ import (
 	"html"
 	"net/http"
 
-	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/public"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/web"
@@ -25,11 +24,8 @@ func Routes() *web.Router {
 	base.Methods("GET, HEAD", "/assets/*", public.FileHandlerFunc())
 
 	r := web.NewRouter()
-	if sessionMid, err := common.Sessioner(); err == nil && sessionMid != nil {
-		r.Use(sessionMid, Contexter())
-	} else {
-		log.Fatal("common.Sessioner failed: %v", err)
-	}
+	r.Use(common.MustInitSessioner(), installContexter())
+
 	r.Get("/", Install) // it must be on the root, because the "install.js" use the window.location to replace the "localhost" AppURL
 	r.Post("/", web.Bind(forms.InstallForm{}), SubmitInstall)
 	r.Get("/post-install", InstallDone)

routers/web/auth/oauth.go

@@ -277,8 +277,11 @@ type LinkAccountData struct {
 	GothUser     goth.User
 }
 
+func init() {
+	gob.Register(LinkAccountData{}) // TODO: CHI-SESSION-GOB-REGISTER
+}
+
 func oauth2GetLinkAccountData(ctx *context.Context) *LinkAccountData {
-	gob.Register(LinkAccountData{})
 	v, ok := ctx.Session.Get("linkAccountData").(LinkAccountData)
 	if !ok {
 		return nil
@@ -287,7 +290,6 @@ func oauth2GetLinkAccountData(ctx *context.Context) *LinkAccountData {
 }
 
 func Oauth2SetLinkAccountData(ctx *context.Context, linkAccountData LinkAccountData) error {
-	gob.Register(LinkAccountData{})
 	return updateSession(ctx, nil, map[string]any{
 		"linkAccountData": linkAccountData,
 	})

routers/web/web.go

@@ -267,11 +267,7 @@ func Routes() *web.Router {
 	routes.Get("/ssh_info", misc.SSHInfo)
 	routes.Get("/api/healthz", healthcheck.Check)
 
-	if sessionMid, err := common.Sessioner(); err == nil && sessionMid != nil {
-		mid = append(mid, sessionMid, context.Contexter())
-	} else {
-		log.Fatal("common.Sessioner failed: %v", err)
-	}
+	mid = append(mid, common.MustInitSessioner(), context.Contexter())
 
 	// Get user from session if logged in.
 	mid = append(mid, webAuth(buildAuthGroup()))