ruby-on-rails - ruby NoMethodError : undefined method `messages' for []:Array

Question

由于谷歌没有帮助我解决这个问题，我想我会把它分享给遇到这个问题的其他人:

尝试保存模型时，我得到

NoMethodError: undefined method `messages' for []:Array
0: /.../active_record/autosave_association.rb:491:in `_ensure_no_duplicate_errors'
1: /.../active_support/callbacks.rb:413:in `block in make_lambda'
2: /.../active_support/callbacks.rb:246:in `block in halting'
3: /.../active_support/callbacks.rb:511:in `block in invoke_after'
4: /.../active_support/callbacks.rb:511:in `each'
5: /.../active_support/callbacks.rb:511:in `invoke_after'
6: /.../active_support/callbacks.rb:132:in `run_callbacks'
7: /.../active_support/callbacks.rb:825:in `_run_validation_callbacks'
8: /.../active_model/validations/callbacks.rb:110:in `run_validations!'
9: /.../active_model/validations.rb:335:in `valid?'

示例模型:

class Foo < ActiveRecord::Base

  def do_stuff
    @errors = []
    @errors << 'Bad stuff' if self.bar > 4
    @errors
  end

end

示例代码:

foo = Foo.first
foo.do_stuff
foo.save # or foo.valid?, etc.

Answer 1

原因

此错误消息的原因是 Foo 类创建了一个实例级别的 @errors 变量。

ActiveRecord 在模型的 errors 变量中跟踪数据库错误。当您尝试验证模型时，它会检查此变量中的错误消息。

解决方案

将 @errors 更改为不同的名称(例如 @foo_errors)。