添加dependent: :destroy后仍无法删除Article，违反外键约束

问题 #

作为Ruby on Rails新手，我在Fly.io上部署了一个简单Web应用，包含Article和Comment两个模型，Article关联多个Comment。当删除带有Comment的Article时，系统提示violate foreign key constraints。在Article模型中添加dependent: :destroy后，问题依旧存在。

排查验证 #

本地Rails控制台测试destroy操作，能正常完成删除流程：

#<Article:0x00007f6d5f437d20
 id: 3,
 title: "My frist article",
 body: "This is my first article",
 created_at: Tue, 04 Jul 2023 01:05:35.148856000 UTC +00:00,
 updated_at: Tue, 04 Jul 2023 01:05:35.148856000 UTC +00:00>

#<Comment:0x00007f6d5f486f88
 id: 6,
 commenter: "Thao",
 body: "This is a comment from Thao",
 article_id: 3,
 created_at: Tue, 04 Jul 2023 01:07:52.288576000 UTC +00:00,
 updated_at: Tue, 04 Jul 2023 01:07:52.288576000 UTC +00:00>

> a1.destroy 
TRANSACTION (0.1ms)  begin transaction
  Comment Load (0.2ms)  SELECT "comments".* FROM "comments" WHERE "comments"."article_id" = ?  [["article_id", 3]]
  Comment Destroy (0.2ms)  DELETE FROM "comments" WHERE "comments"."id" = ?  [["id", 6]]
  Article Destroy (0.2ms)  DELETE FROM "articles" WHERE "articles"."id" = ?  [["id", 3]]
  TRANSACTION (7.2ms)  commit transaction
=> 
#<Article:0x00007f6d5f437d20
 id: 3,
 title: "My frist article",
 body: "This is my first article",
 created_at: Tue, 04 Jul 2023 01:05:35.148856000 UTC +00:00,
 updated_at: Tue, 04 Jul 2023 01:05:35.148856000 UTC +00:00>

日志显示事务会先加载关联的Comment，删除后再删除Article，符合dependent: :destroy的预期行为。

解决方法 #

重新部署Fly.io应用后，问题彻底解决。

原因 #

Fly.io平台未自动更新部署的代码，添加dependent: :destroy后的修改没有同步到线上环境。

相关代码 #

模型代码 #

class Article < ApplicationRecord
  has_many :comments, dependent: :destroy
end
class Comment < ApplicationRecord
  belongs_to :article
end

Schema文件 #

ActiveRecord::Schema[7.0].define(version: 2023_06_22_082322) do
  create_table "articles", force: :cascade do |t|
    t.string "title"
    t.text "body"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
  end

  create_table "comments", force: :cascade do |t|
    t.string "commenter"
    t.text "body"
    t.integer "article_id", null: false
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.index ["article_id"], name: "index_comments_on_article_id"
  end

  add_foreign_key "comments", "articles"
end

内容的提问来源于stack exchange，提问作者Thảo Nguyễn