ArgumentError: The scope body needs to be callable

Question

我在插件中定义了以下方法：

class ReArtifactProperties < ActiveRecord::Base
  unloadable

  #attr_accessible :artifact_type

  scope :without_projects, :conditions => ["artifact_type != ?", 'Project']
  scope :of_project, lambda { |project|
    project_id = (project.is_a? Project) ? project.id : project
    {:conditions => {:project_id => project_id}}
  }

Answer 1

您的代码有几个问题，其中一些违反了 Ruby 的语法规则，而另一些则违反了 Rails 的 return 值要求。

当前错误的原因是语法错误。 lambda 的块必须在与 lambda 方法相同的行中定义。

现在，如果您已修复此问题，您会注意到一旦您使用范围，您的代码就会抛出其他异常。原因是范围的 return 值应该是一个 ActiveRecord 关系，而不仅仅是一个简单的哈希。

因此，您的范围定义应与此类似：

scope :of_project, lambda { |project|
  project_id = (project.is_a? Project) ? project.id : project
  where(:project_id => project_id)
}

既然 Rails 足够聪明，可以弄清楚如何从对象中获取 ID 以进行查询，您甚至可以摆脱其中的 project_id 逻辑并缩小范围定义为

scope :of_project, lambda { |project|
  where(:project_id => project)
}

Answer 2

Your code has several issues, some of which are violations of syntax rules of Ruby, while others violate return value requirements of Rails.

是的，关于 lambda 块，你是对的

最初的代码是：

scope :of_project, lambda { |project|
    project_id = (project.is_a? Project) ? project.id : project
    {:conditions => {:project_id => project_id}}
  }

修正后，缩减为：

scope :of_project, lambda { |project|
  project_id = (project.is_a? Project) ? project.id : project
  where(:project_id => project_id)
}

Now given that Rails is smart enough to figure out how to get the ID from an object for a query,

了解我从

http://rubyonrails.org/

学到的MVC架构如何理解RAILS w.r.t Redmine Tool 的核心功能？它使用的mysql 默认数据库有一个非常庞大的模型结构currently.Could 将其简化以了解Rails?

的核心功能

ArgumentError: The scope body needs to be callable

ArgumentError: The scope body needs to be callable

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