Rails: how to disable before_destroy callback when it's being destroyed because of the parent is being destroyed (:dependent => :destroy)

Question

I have two classes: Parent and Child with

Child:

belongs_to :parent

and

Parent

has_many :children, :dependent          


        

Answer 1

carp's answer above will work if you set prepend to true on the before_destroy method. Try this:

Child:

belongs_to :parent
before_destroy :prevent_destroy
attr_accessor :destroyed_by_parent

...

private

def prevent_destroy
  if !destroyed_by_parent
    self.errors[:base] << "You may not delete this child."
    return false
  end
end

Parent:

has_many :children, :dependent => :destroy
before_destroy :set_destroyed_by_parent, prepend: true

...

private

def set_destroyed_by_parent
  children.each{ |child| child.destroyed_by_parent = true }
end

We had to do this because we're using Paranoia, and dependent: delete_all would hard-delete rather than soft-delete them. My gut tells me there's a better way to do this, but it's not obvious, and this gets the job done.