fix: check oauthUser.Username length

controller/oauth.go

@@ -240,9 +240,12 @@ func findOrCreateOAuthUser(c *gin.Context, provider oauth.Provider, oauthUser *o
 
 	if oauthUser.Username != "" {
 		if exists, err := model.CheckUserExistOrDeleted(oauthUser.Username, ""); err == nil && !exists {
+			// 防止索引退化
+			if len(oauthUser.Username) <= model.UserNameMaxLength {
 				user.Username = oauthUser.Username
 			}
 		}
+	}
 
 	if oauthUser.DisplayName != "" {
 		user.DisplayName = oauthUser.DisplayName

model/user.go

@@ -15,6 +15,8 @@ import (
 	"gorm.io/gorm"
 )
 
+const UserNameMaxLength = 20
+
 // User if you add sensitive fields, don't forget to clean them in setupLogin function.
 // Otherwise, the sensitive information will be saved on local storage in plain text!
 type User struct {