明确显示系统通知地址只发不收的投递失败原因

backend/services/logstore/mail.go

@@ -9,6 +9,8 @@ import (
 	"net/textproto"
 	"strconv"
 	"time"
+
+	"git.pcux.cn/xuans/Smail/utils/validation"
 )
 
 type MailDetails struct {
@@ -25,6 +27,8 @@ func MailFailureReason(err error) string {
 	var protocol *textproto.Error
 	var network net.Error
 	switch {
+	case errors.Is(err, validation.ErrNotificationRecipient):
+		return "系统通知地址仅用于发信，不接受收信，请改用普通邮箱地址"
 	case errors.As(err, &certificate):
 		return "对端证书验证失败"
 	case errors.As(err, &dns):

backend/utils/send/send.go

@@ -136,7 +136,7 @@ func parseRecipientAddress(user *parsemail.User) (string, string, error) {
 	}
 	address := strings.TrimSpace(user.EmailAddress)
 	if validation.IsNotificationAddress(address, config.CurrentMailDomains().Accepted) {
-		return address, "", errors.New("notification address does not accept mail")
+		return address, "", validation.ErrNotificationRecipient
 	}
 	if address == "" || address != user.EmailAddress {
 		return address, "", errors.New("recipient address is empty or contains surrounding whitespace")

backend/utils/validation/notification.go

@@ -1,6 +1,11 @@
 package validation
 
-import "strings"
+import (
+	"errors"
+	"strings"
+)
+
+var ErrNotificationRecipient = errors.New("notification address does not accept mail")
 
 // 加号不属于可注册账号字符，保留地址不会占用普通用户的邮箱。
 const NotificationLocalPart = "notification+system"