Avoid cycle-redirecting user/login page (#28636) (#28658)

Backport #28636

Fix #28231, and remove some unused code.

models/auth/source.go

@@ -275,9 +275,6 @@ func ActiveSources(tp Type) ([]*Source, error) {
 // IsSSPIEnabled returns true if there is at least one activated login
 // source of type LoginSSPI
 func IsSSPIEnabled() bool {
-	if !db.HasEngine {
-		return false
-	}
 	sources, err := ActiveSources(SSPI)
 	if err != nil {
 		log.Error("ActiveSources: %v", err)

models/db/engine.go

@@ -27,9 +27,6 @@ var (
 	x         *xorm.Engine
 	tables    []any
 	initFuncs []func() error
-
-	// HasEngine specifies if we have a xorm.Engine
-	HasEngine bool
 )
 
 // Engine represents a xorm engine or session.

modules/setting/server.go

@@ -343,8 +343,7 @@ func loadServerFrom(rootCfg ConfigProvider) {
 		LandingPageURL = LandingPageOrganizations
 	case "login":
 		LandingPageURL = LandingPageLogin
-	case "":
+	case "", "home":
-	case "home":
 		LandingPageURL = LandingPageHome
 	default:
 		LandingPageURL = LandingPage(landingPage)

routers/common/db.go

@@ -37,7 +37,6 @@ func InitDBEngine(ctx context.Context) (err error) {
 		log.Info("Backing off for %d seconds", int64(setting.Database.DBConnectBackoff/time.Second))
 		time.Sleep(setting.Database.DBConnectBackoff)
 	}
-	db.HasEngine = true
 	config.SetDynGetter(system_model.NewDatabaseDynKeyGetter())
 	return nil
 }

routers/web/auth/auth.go

@@ -45,10 +45,6 @@ const (
 
 // AutoSignIn reads cookie and try to auto-login.
 func AutoSignIn(ctx *context.Context) (bool, error) {
-	if !db.HasEngine {
-		return false, nil
-	}
-
 	uname := ctx.GetSiteCookie(setting.CookieUserName)
 	if len(uname) == 0 {
 		return false, nil
@@ -130,7 +126,11 @@ func checkAutoLogin(ctx *context.Context) bool {
 
 	if isSucceed {
 		middleware.DeleteRedirectToCookie(ctx.Resp)
-		ctx.RedirectToFirst(redirectTo, setting.AppSubURL+string(setting.LandingPageURL))
+		nextRedirectTo := setting.AppSubURL + string(setting.LandingPageURL)
+		if setting.LandingPageURL == setting.LandingPageLogin {
+			nextRedirectTo = setting.AppSubURL + "/" // do not cycle-redirect to the login page
+		}
+		ctx.RedirectToFirst(redirectTo, nextRedirectTo)
 		return true
 	}