Rails - Jun 2013 - ActiveRecord::Base.transaction - SystemStackError - stack level too deep:

Im having an issue that seems to only happen when trying to use a 
transaction. Ive used transactions many times in the past and Im at a loss 
as to why im getting the stack level too deep problem.

SystemStackError - stack level too deep:
  actionpack (3.2.13) lib/action_dispatch/middleware/reloader.rb:70:in
`''

I have a StackOveflow with more detail - 
http://stackoverflow.com/q/16930511/1408461

As stated in the SO. If I try to save the record to the database outside 
the transaction it saves just fine. I only get the error in the 
transaction. 

Params Object

params => {
  "resource"=> {
    "resource_type"=>"document", 
    "resource_name"=>"My Rails Doc",
    "source_id"=>"Dropbox"
  },
  "resource_document"=> {
    "resource_document"=>
#<ActionDispatch::Http::UploadedFile:0x007f8e919d06f8
      @content_type="text/plain",
      @headers= "Content-Disposition: 
        form-data; name=\"resource_document[resource_document]\";
        filename=\"rails_local_env_setup.txt\"\r\n
        Content-Type: text/plain\r\n",
      @original_filename="rails_local_env_setup.txt",
      @tempfile=
#<File:/var/folders/t4/lfmj7mhj52b2krryzh7dj4hh0000gn/T/RackMultipart20130604-29589-2c0seo>>},

  "action"=>"create",
  "controller"=>"resources"
 }

**Controller**

def create

  if current_teacher
    @resource = ResourceObject.create_teacher_resource(params, current_teacher)
  end

  if current_student
    @resource = ResourceObject.create_student_resource(params, current_student)
  end

  if current_admin
    @resource = Resource.new(params[:resource])
  end

  respond_to do |format|
    if @resource.success
      format.html { redirect_to @resource, notice: ''Resource was
successfully created.'' }
      format.json { render json: @resource, status: :created, location:
@resource }
    else
      format.html { render action: "new" }
      format.json { render json: @resource.errors, status: :unprocessable_entity
}
    end
  endend

**Transaction**

class ResourceObject

  def self.create_teacher_resource(params, teacher)
    begin
      ActiveRecord::Base.transaction do
        # Create Resource
        @resource = Resource.new
        @resource.resource_name = params[:resource][:resource_name]
        @resource.resource_type = params[:resource][:resource_type]
        @resource.source_id = params[:resource][:source_id]
        @resource.teacher_id = teacher.id
        @resource.save

        # Create Resource Document
        @resource_document = ResourceDocument.new
        @resource_document.resource_document =
params[:resource_document][:resource_document]
        @resource_document.resource_id = @resource.id
        @resource_document.save

        # TODO Add Commom Core Joins
        # TODO Video Uploader
        # TODO Image Uploader

        return @resource.success = "ok"
      end
        rescue Exception => e
      # TODO Need to figure out how to pass exception message back to controller
          return @resource.errors
        end     
      end
    end

end

Resource Model

class Resource < ActiveRecord::Base include TransactionAttributes 
attr_accessible :resource_name, :resource_type, :source_id, :teacher_id, 
:student_id, :success, :errors belongs_to :teacher, :class_name => 
"Teacher", :foreign_key => "teacher_id" belongs_to
:student, :class_name =>
"Student", :foreign_key => "student_id" has_many
:resource_documents #
has_many :resource_images # has_many :resource_videos # has_many 
:question_resources # has_many :assignment_resources end

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On Saturday, 22 June 2013 16:06:54 UTC-7, Bob O wrote:
>
> Im having an issue that seems to only happen when trying to use a 
> transaction. Ive used transactions many times in the past and Im at a loss 
> as to why im getting the stack level too deep problem.
>
> SystemStackError - stack level too deep:
>   actionpack (3.2.13) lib/action_dispatch/middleware/reloader.rb:70:in
`''
>
> I have a StackOveflow with more detail - 
> http://stackoverflow.com/q/16930511/1408461
>
> As stated in the SO. If I try to save the record to the database outside 
> the transaction it saves just fine. I only get the error in the 
> transaction. 
>
> Params Object
>
> params => {
>   "resource"=> {
>     "resource_type"=>"document", 
>     "resource_name"=>"My Rails Doc",
>     "source_id"=>"Dropbox"
>   },
>   "resource_document"=> {
>     "resource_document"=>
#<ActionDispatch::Http::UploadedFile:0x007f8e919d06f8
>       @content_type="text/plain",
>       @headers= "Content-Disposition: 
>         form-data; name=\"resource_document[resource_document]\";
>         filename=\"rails_local_env_setup.txt\"\r\n
>         Content-Type: text/plain\r\n",
>       @original_filename="rails_local_env_setup.txt",
>       @tempfile=
#<File:/var/folders/t4/lfmj7mhj52b2krryzh7dj4hh0000gn/T/RackMultipart20130604-29589-2c0seo>>},
>
>   "action"=>"create",
>   "controller"=>"resources"
>  }
>
> **Controller**
>
> def create
>
>   if current_teacher
>     @resource = ResourceObject.create_teacher_resource(params,
current_teacher)
>   end
>
>   if current_student
>     @resource = ResourceObject.create_student_resource(params,
current_student)
>   end
>
>   if current_admin
>     @resource = Resource.new(params[:resource])
>   end
>
>   respond_to do |format|
>     if @resource.success
>       format.html { redirect_to @resource, notice: ''Resource was
successfully created.'' }
>       format.json { render json: @resource, status: :created, location:
@resource }
>     else
>       format.html { render action: "new" }
>       format.json { render json: @resource.errors, status:
:unprocessable_entity }
>     end
>   endend
>
> **Transaction**
>
> class ResourceObject
>
>   def self.create_teacher_resource(params, teacher)
>     begin
>       ActiveRecord::Base.transaction do
>         # Create Resource
>         @resource = Resource.new
>         @resource.resource_name = params[:resource][:resource_name]
>         @resource.resource_type = params[:resource][:resource_type]
>         @resource.source_id = params[:resource][:source_id]
>         @resource.teacher_id = teacher.id
>         @resource.save
>
>         # Create Resource Document
>         @resource_document = ResourceDocument.new
>         @resource_document.resource_document =
params[:resource_document][:resource_document]
>         @resource_document.resource_id = @resource.id
>         @resource_document.save
>
>         # TODO Add Commom Core Joins
>         # TODO Video Uploader
>         # TODO Image Uploader
>
>         return @resource.success = "ok"
>       end
>         rescue Exception => e
>
>
A style note here: rescuing Exception is not typically what you want. See 
this for more details:

http://stackoverflow.com/questions/10048173/why-is-it-bad-style-to-rescue-exception-e-in-ruby
 
>
>       # TODO Need to figure out how to pass exception message back to
controller
>           return @resource.errors
>         end     
>       end
>     end
>
> end
>
> Resource Model
>
> class Resource < ActiveRecord::Base include TransactionAttributes 
>
>
I''d be curious as to what''s in this module - it could be
relevant...
 
>
>   attr_accessible :resource_name, :resource_type, :source_id, :teacher_id,
:student_id, :success, :errors
>
>
 :errors here is not useful - attr_accessible controls mass-assignment of 
attributes (as when you do Resource.new(:param1 => ''foo'',
:param2 =>
''bar''). You almost certainly do not want to mass-assign an
internal part of
ActiveRecord. :)

  belongs_to :teacher, :class_name => "Teacher", :foreign_key =>
"teacher_id"
>   belongs_to :student, :class_name => "Student", :foreign_key
=> "student_id"
>
>
Another minor (not terribly relevant) style note: :class_name and 
:foreign_key are both redundant here, as the values specified are the same 
as the ActiveRecord defaults. 

Next steps for debugging this:

- it would be useful to see the code for the TransactionAttributes module 
you''re including. Perhaps something is hitting an internal method and 
making a mess.

- showing the DB schema would help as well; again, having fields with names 
that clash with ActiveRecord''s can cause peculiar behavior.

- a full stack trace might shed some light; especially in the case of 
StackLevelTooDeep, the final line isn''t always helpful.

--Matt Jones

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This is the TransactionAttributes

module TransactionAttributes

  def success
    success
  end

  def success=(success)
    self.success = success
  end

  def errors
  errors
  end

  def errors=(errors)
  self.errors = errors
  end
end

The reason for these was i was trying to set a property on a returned 
object or the errors. I yet to figure out a way i can return a more 
descriptive error message from the transaction back to the controller. 

I''ll fix the style note. That just happens to populate when using a tab
trigger in Sublime.

This is the table schema

# == Schema Information
#
# Table name: resources
#
#  id            :integer          not null, primary key
#  resource_name :string(255)
#  teacher_id    :integer
#  student_id    :integer
#  source_id     :string(255)
#  created_at    :datetime         not null
#  updated_at    :datetime         not null
#  resource_type :string(255)
#

The SystemStackError - stack level too deep:
  actionpack (3.2.13) lib/action_dispatch/middleware/reloader.rb:70:in
`''
is the only thing i get in the console.

This is whats returned in the response.

SystemStackError at /resources
=============================
> stack level too deep
actionpack (3.2.13) lib/action_dispatch/middleware/reloader.rb, line 70
-----------------------------------------------------------------------

``` ruby
65 response = @app.call(env)
66 response[2] = ActionDispatch::BodyProxy.new(response[2]) { cleanup! }
67 response
68 rescue Exception
69 cleanup!
> 70 raise
71 end
72 
73 def prepare! #:nodoc:
74 run_callbacks :prepare if validated?
75 end
```

App backtrace
-------------



Full backtrace
--------------

- actionpack (3.2.13) lib/action_dispatch/middleware/reloader.rb:70:in
`''


based on a SO i read it said to turn on 
the Rails.backtrace_cleaner.remove_silencers!

so ive dont that.

Is there something else i can do to that would be helpful?


On Saturday, June 22, 2013 5:06:54 PM UTC-6, Bob O
wrote:
>
> Im having an issue that seems to only happen when trying to use a 
> transaction. Ive used transactions many times in the past and Im at a loss 
> as to why im getting the stack level too deep problem.
>
> SystemStackError - stack level too deep:
>   actionpack (3.2.13) lib/action_dispatch/middleware/reloader.rb:70:in
`''
>
> I have a StackOveflow with more detail - 
> http://stackoverflow.com/q/16930511/1408461
>
> As stated in the SO. If I try to save the record to the database outside 
> the transaction it saves just fine. I only get the error in the 
> transaction. 
>
> Params Object
>
> params => {
>   "resource"=> {
>     "resource_type"=>"document", 
>     "resource_name"=>"My Rails Doc",
>     "source_id"=>"Dropbox"
>   },
>   "resource_document"=> {
>     "resource_document"=>
#<ActionDispatch::Http::UploadedFile:0x007f8e919d06f8
>       @content_type="text/plain",
>       @headers= "Content-Disposition: 
>         form-data; name=\"resource_document[resource_document]\";
>         filename=\"rails_local_env_setup.txt\"\r\n
>         Content-Type: text/plain\r\n",
>       @original_filename="rails_local_env_setup.txt",
>       @tempfile=
#<File:/var/folders/t4/lfmj7mhj52b2krryzh7dj4hh0000gn/T/RackMultipart20130604-29589-2c0seo>>},
>
>   "action"=>"create",
>   "controller"=>"resources"
>  }
>
> **Controller**
>
> def create
>
>   if current_teacher
>     @resource = ResourceObject.create_teacher_resource(params,
current_teacher)
>   end
>
>   if current_student
>     @resource = ResourceObject.create_student_resource(params,
current_student)
>   end
>
>   if current_admin
>     @resource = Resource.new(params[:resource])
>   end
>
>   respond_to do |format|
>     if @resource.success
>       format.html { redirect_to @resource, notice: ''Resource was
successfully created.'' }
>       format.json { render json: @resource, status: :created, location:
@resource }
>     else
>       format.html { render action: "new" }
>       format.json { render json: @resource.errors, status:
:unprocessable_entity }
>     end
>   endend
>
> **Transaction**
>
> class ResourceObject
>
>   def self.create_teacher_resource(params, teacher)
>     begin
>       ActiveRecord::Base.transaction do
>         # Create Resource
>         @resource = Resource.new
>         @resource.resource_name = params[:resource][:resource_name]
>         @resource.resource_type = params[:resource][:resource_type]
>         @resource.source_id = params[:resource][:source_id]
>         @resource.teacher_id = teacher.id
>         @resource.save
>
>         # Create Resource Document
>         @resource_document = ResourceDocument.new
>         @resource_document.resource_document =
params[:resource_document][:resource_document]
>         @resource_document.resource_id = @resource.id
>         @resource_document.save
>
>         # TODO Add Commom Core Joins
>         # TODO Video Uploader
>         # TODO Image Uploader
>
>         return @resource.success = "ok"
>       end
>         rescue Exception => e
>       # TODO Need to figure out how to pass exception message back to
controller
>           return @resource.errors
>         end     
>       end
>     end
>
> end
>
> Resource Model
>
> class Resource < ActiveRecord::Base include TransactionAttributes 
> attr_accessible :resource_name, :resource_type, :source_id, :teacher_id, 
> :student_id, :success, :errors belongs_to :teacher, :class_name => 
> "Teacher", :foreign_key => "teacher_id" belongs_to
:student, :class_name =>
> "Student", :foreign_key => "student_id" has_many
:resource_documents #
> has_many :resource_images # has_many :resource_videos # has_many 
> :question_resources # has_many :assignment_resources end
>
>
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On Sunday, 23 June 2013 20:22:26 UTC-7, Bob O wrote:
>
> This is the TransactionAttributes
>
> module TransactionAttributes
>
>   def success
>     success
>   end
>
>   def success=(success)
>     self.success = success
>   end
>
That''s the problem right there - this method is calling itself. If you
want
to define a getter / setter, you should either do this:

def success
  @success
end

def success=(value)
  @success = value
end

---
Or this (preferred, if you''re just storing a value, as above):

attr_accessor :success

 
>   def errors
>   errors
>   end
>
>   def errors=(errors)
>   self.errors = errors
>   end
> end
>
These will break some things - ActiveRecord already defines an `errors` 
method + `errors=` assignment operator, and expects them to behave in a 
particular way (for instance, the validations assume that you can make 
calls like `some_model.errors.add(:some_attribute,
''message'')`).

I highly recommend reading through the guides 
(http://guides.rubyonrails.org/) or following some of Michael Hartl''s 
excellent tutorial (http://ruby.railstutorial.org/) in preference to 
digging through Stack Overflow - the answers there are incredibly useful if 
you''ve got a highly specific problem, but they can sometimes miss the 
bigger picture.

Hope this helps,

--Matt Jones

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Thanks Matt. That was the problem. At one point I had pulled those out, or 
at least I thought I did. I guess thats why I was confused. Anyway. Thanks 
For the help. I do have Michaels stuff. Its very good. My setters were a 
rookie mistake. 

One thing that I wish i could find more stuff about is transactions. Most 
examples seem to handle the transactions in the controller which I dont 
like. So I have troubles getting the errors back to the controller for 
better user feedback. Hence the reason I was trying to use the 
TransactionAttributes module. Backfire!

Appreciate your help.

Bob

On Saturday, June 22, 2013 5:06:54 PM UTC-6, Bob O
wrote:
>
> Im having an issue that seems to only happen when trying to use a 
> transaction. Ive used transactions many times in the past and Im at a loss 
> as to why im getting the stack level too deep problem.
>
> SystemStackError - stack level too deep:
>   actionpack (3.2.13) lib/action_dispatch/middleware/reloader.rb:70:in
`''
>
> I have a StackOveflow with more detail - 
> http://stackoverflow.com/q/16930511/1408461
>
> As stated in the SO. If I try to save the record to the database outside 
> the transaction it saves just fine. I only get the error in the 
> transaction. 
>
> Params Object
>
> params => {
>   "resource"=> {
>     "resource_type"=>"document", 
>     "resource_name"=>"My Rails Doc",
>     "source_id"=>"Dropbox"
>   },
>   "resource_document"=> {
>     "resource_document"=>
#<ActionDispatch::Http::UploadedFile:0x007f8e919d06f8
>       @content_type="text/plain",
>       @headers= "Content-Disposition: 
>         form-data; name=\"resource_document[resource_document]\";
>         filename=\"rails_local_env_setup.txt\"\r\n
>         Content-Type: text/plain\r\n",
>       @original_filename="rails_local_env_setup.txt",
>       @tempfile=
#<File:/var/folders/t4/lfmj7mhj52b2krryzh7dj4hh0000gn/T/RackMultipart20130604-29589-2c0seo>>},
>
>   "action"=>"create",
>   "controller"=>"resources"
>  }
>
> **Controller**
>
> def create
>
>   if current_teacher
>     @resource = ResourceObject.create_teacher_resource(params,
current_teacher)
>   end
>
>   if current_student
>     @resource = ResourceObject.create_student_resource(params,
current_student)
>   end
>
>   if current_admin
>     @resource = Resource.new(params[:resource])
>   end
>
>   respond_to do |format|
>     if @resource.success
>       format.html { redirect_to @resource, notice: ''Resource was
successfully created.'' }
>       format.json { render json: @resource, status: :created, location:
@resource }
>     else
>       format.html { render action: "new" }
>       format.json { render json: @resource.errors, status:
:unprocessable_entity }
>     end
>   endend
>
> **Transaction**
>
> class ResourceObject
>
>   def self.create_teacher_resource(params, teacher)
>     begin
>       ActiveRecord::Base.transaction do
>         # Create Resource
>         @resource = Resource.new
>         @resource.resource_name = params[:resource][:resource_name]
>         @resource.resource_type = params[:resource][:resource_type]
>         @resource.source_id = params[:resource][:source_id]
>         @resource.teacher_id = teacher.id
>         @resource.save
>
>         # Create Resource Document
>         @resource_document = ResourceDocument.new
>         @resource_document.resource_document =
params[:resource_document][:resource_document]
>         @resource_document.resource_id = @resource.id
>         @resource_document.save
>
>         # TODO Add Commom Core Joins
>         # TODO Video Uploader
>         # TODO Image Uploader
>
>         return @resource.success = "ok"
>       end
>         rescue Exception => e
>       # TODO Need to figure out how to pass exception message back to
controller
>           return @resource.errors
>         end     
>       end
>     end
>
> end
>
> Resource Model
>
> class Resource < ActiveRecord::Base include TransactionAttributes 
> attr_accessible :resource_name, :resource_type, :source_id, :teacher_id, 
> :student_id, :success, :errors belongs_to :teacher, :class_name => 
> "Teacher", :foreign_key => "teacher_id" belongs_to
:student, :class_name =>
> "Student", :foreign_key => "student_id" has_many
:resource_documents #
> has_many :resource_images # has_many :resource_videos # has_many 
> :question_resources # has_many :assignment_resources end
>
>
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