version_at throws an error

[JacobEvelyn]

I'm using a separate version class for each of my versioned models, and when I call object.version_at(timestamp) I unfortunately get:

PG::SyntaxError: ERROR:  zero-length delimited identifier at or near """"
LINE 1: SELECT  "".* FROM ""  WHERE (created_at > '2013-09-08 16:56:...

Looks like the versions table and columns aren't getting found properly. Is this a known issue?

[batter]

Which version of PaperTrail are you using? Also, please make sure you have read and followed directions in the README about how to use custom version classes.

[JacobEvelyn]

Thanks for the quick response. I'm using PaperTrail 3.0.0.beta1, and I've followed the directions on the README. Additionally, it seems the self.table_name = ... line that the README says to put into versions classes may be unnecessary (the rest of PaperTrail works without it for me).

[batter]

So you've definitely passed in the :class_name option into your has_paper_trail declarations on each model?

[JacobEvelyn]

Yep.

[batter]

Please try running this in your console. Say you have a model named Widget that declares has_paper_trail.

> Widget.version_class_name
=> "PaperTrail::Version" # this is the default value, wondering what yours returns
> Widget.versions_association_name
=> :versions # again, this is the default value, wondering what yours returns

In fact it would be helpful if you could provide a gist or a copy of the code for one of the models and it's counterpart custom version class. I'm having difficulty helping to debug with the limited information you've provided. Thanks.

[JacobEvelyn]

Sure thing. Here are the relevant parts of my model:

module SIS
  class CourseSection < ActiveRecord::Base

    # Set up PaperTrail versioning.
    has_paper_trail class_name: "SIS::CourseSectionVersion",
                    meta: { :import_create => :import_create } # This is used when importing data.
    attr_accessor :import_create
  end

  class CourseSectionVersion < PaperTrail::Version
    # self.table_name is unnecessary here
    self.sequence_name = :course_section_version_id_sequence
  end
end

And I also have sis.rb:

module SIS
  def self.table_name_prefix
    'sis_'
  end
end

My tables are named sis_course_sections and sis_course_section_versions.

And, in the console, I have:

> SIS::CourseSection.version_class_name
=> "SIS::CourseSectionVersion" 
> SIS::CourseSection.versions_association_name
=> :versions 

Thanks for all the help.

[batter]

And you also added an initializer like so (as the README states is necessary for custom version classes)?

# config/initializers/paper_trail.rb
PaperTrail::Version.module_eval do
  self.abstract_class = true
end

[JacobEvelyn]

Yes, I have that initializer as well.

[batter]

@JacobEvelyn - Think I figured out the issue and fixed it with eb01ca3. Please try using the head of the master branch from GitHub and see if that fixes the issue. Add this to your Gemfile:

gem 'paper_trail', :github => 'airblade/paper_trail'

[JacobEvelyn]

Ah, beautiful! Works perfectly. Thanks for the help and the quick fix!