Weird things on String Column error: "some_column_name is required".

[zw963]

Hi, Following is a example.

I have a SysConfig class like this:

class SysConfig < BaseModel
  table do
    column private_key : String
    column deleted_at : Time?
  end

  def self.current
    CreateSysConfig.create!(private_key: "", deleted_at: nil)
  end
end

I use ActiveRecord migration for create this table, following is migration.

class CreateSysConfigs < ActiveRecord::Migration[7.0]
  def change
    create_table :sys_configs, comment: '系统配置' do |t|
      t.text :private_key, comment: '私钥'
      t.datetime :deleted_at, comment: '删除时间'

      t.timestamps
    end
  end
end

Following is my CreateSysConfig:

class CreateSysConfig < SysConfig::SaveOperation
  permit_columns private_key, deleted_at
end

The Weired thing is, when i run SysConfig.current, i get following backtrace:

Exception: Could not perform CreateSysConfig.

  ▸ private_key: is required
 (Avram::InvalidOperationError)
  from lib/avram/src/avram/save_operation.cr:347:7 in 'save!'
  from src/operations/create_sys_config.cr:1:1 in 'create!:private_key:deleted_at'
  from src/models/sys_config.cr:8:5 in 'current'
  from src/project_root.cr:30:1 in '->'
  from lib/kemal/src/kemal/route.cr:12:26 in '->'
  from lib/kemal/src/kemal/route_handler.cr:49:39 in 'process_request'
  from lib/kemal/src/kemal/route_handler.cr:17:7 in 'call'
  from /usr/share/crystal/src/http/server/handler.cr:28:7 in 'call_next'
  from lib/kemal/src/kemal/websocket_handler.cr:13:14 in 'call'
  from /usr/share/crystal/src/http/server/handler.cr:28:7 in 'call_next'
  from lib/kemal/src/kemal/filter_handler.cr:21:7 in 'call'
  from /usr/share/crystal/src/http/server/handler.cr:28:7 in 'call_next'
  from lib/kemal/src/kemal/static_file_handler.cr:75:9 in 'call'
  from /usr/share/crystal/src/http/server/handler.cr:28:7 in 'call_next'
  from lib/kemal/src/kemal/exception_handler.cr:8:7 in 'call'
  from /usr/share/crystal/src/http/server/handler.cr:28:7 in 'call_next'
  from lib/kemal/src/kemal/log_handler.cr:8:37 in 'call'
  from /usr/share/crystal/src/http/server/handler.cr:28:7 in 'call_next'
  from lib/kemal/src/kemal/init_handler.cr:12:7 in 'call'
  from /usr/share/crystal/src/http/server/request_processor.cr:51:11 in 'process'
  from /usr/share/crystal/src/http/server.cr:515:5 in 'handle_client'
  from /usr/share/crystal/src/http/server.cr:468:13 in '->'
  from /usr/share/crystal/src/fiber.cr:146:11 in 'run'
  from /usr/share/crystal/src/fiber.cr:98:34 in '->'
  from ???

My question is, why private_key column couldn't accept a empty string "" as value? i could see anywhere have limit for it, in fact, i can even create a new order from rails console all column is nil.

irb(main):002:0> SysConfig.create
  TRANSACTION (0.1ms)  BEGIN
  SysConfig Create (0.5ms)  INSERT INTO "sys_configs" ("private_key", "deleted_at", "created_at", "updated_at") VALUES ($1, $2, $3, $4) RETURNING "id"  [["private_key", "[FILTERED]"], ["deleted_at", nil], ["created_at", "2022-07-11 09:04:02.567781"], ["updated_at", "2022-07-11 09:04:02.567781"]]                         
  TRANSACTION (5.4ms)  COMMIT                                        
=>                                                                   
#<SysConfig:0x00007fd44f3777f8                                       
 id: 3,                                                              
 private_key: nil,                                                   
 deleted_at: nil,                                                    
 created_at: Mon, 11 Jul 2022 09:04:02.567781000 UTC +00:00,
 updated_at: Mon, 11 Jul 2022 09:04:02.567781000 UTC +00:00>

after the above current method change to: CreateSysConfig.create!(private_key: "hello", deleted_at: nil), it works,
so, the private_key must include a non-blank string, how to fix this?
Thank you.

[jwoertink]

In Lucky, we treat "" the same as nil because this helps with additional type-safety. For example, say you have a name column that gets displayed on a page. If it got set to "", the page would render a blank space, and you wouldn't know until production.

We have 2 ways around this:

class CreateSysConfig < SysConfig::SaveOperation
  permit_columns private_key, deleted_at
  # add this to skip validating the required fields
  skip_default_validations
end

or
2.

class CreateSysConfig < SysConfig::SaveOperation
  permit_columns private_key, deleted_at
  
  before_save do
    # allow the private_key to be blank
    private_key.allow_blank = true
  end
end

I think we're missing docs on these, but here's the PR luckyframework/avram#746

[zw963]

I think we're missing docs on these

Yes, i guess we are not mention this in https://luckyframework.org/guides/database/callbacks-and-validations

Thank you.