Has Many Through Association via has_many: and belongs_to: on the join table

[allavena]

I'm reopening #530 (#530) as I'm facing the same issue and don't believe the reference #466) addresses it (Or if it does, I've completely failed to understand)

class Document < ActiveRecord::Base
  has_many :sections
  has_many :paragraphs, through: :sections
end

class Section < ActiveRecord::Base
  belongs_to :document
  has_many :paragraphs
end

class Paragraph < ActiveRecord::Base
  belongs_to :section
end

Paper_Trail 4.0.0 Beta doesn't cater this situation. It looks for foreign key of association Paragraph i.e, section_id in the through model i.e, Section which will not be available in the above mentioned case.

#466 mentions adding an additional column to 'versions' table. However, the data is already there. With the existing code, a query on section can already return its paragraphs and revisions.

[If anything, may I suggest a note in the Readme that this case is not supported?]

Thanks
André

[jaredbeck]

Paper_Trail 4.0.0 Beta doesn't cater this situation.

Currently, paper_trail 4.0.0 is the latest. If you are still using a beta, please upgrade.

It looks for foreign key of association Paragraph i.e, section_id in the through model i.e, Section which will not be available in the above mentioned case.

What PaperTrail methods are you using? reify? You've given some ActiveRecord models, but I don't see anything from PaperTrail in your example.

[allavena]

Bad copy/paste, sorry. I'm using paper trail 4.0.0, although same result with using master from git.

document = FactoryGirl.create(:document_with_sections_and_paragraphs)
puts 'Updating some paragraph'
document.sections[0].paragraphs[0].update_attributes(title: 'New paragraph 1 title')
puts 'Updating a section name'
document.sections[0].update_attributes(title: 'My new Section')
puts 'Updating document itself'
document.update_attributes(title: 'New document Title')
document.sections[0].paragraphs[0].update_attributes(title: 'Very New paragraph 1 title')
puts 'Previous version of document'
pp document.versions.last.reify(:has_many => true)

This last line fails, in the rails console in development mode, with a
NoMethodError: undefined method `section_id' for #Section:0x00000006c6ad58

Note, if I stick that wrap that code in a test, it runs, however, the previous version of the document returns an empty list of sections.

[jaredbeck]

I can't reproduce this issue. Please review the test app I created (https://github.com/jaredbeck/pt_issue_590) and propose (via a PR to the test app) a change which will reproduce the issue. Thanks.

[allavena]

For me, there are two distinct issues. In test mode, behaviour is different than from the console. In test, the old version no longer has the associations - test app shows this. But the crash, I only get in console. I don't know how to reproduce in test mode (I think it would crash there too, if the associations were not lost). Here is the code reproducing the issue in console:

From the console:

ActiveRecord::Migrator.migrate "db/migrate"
d = Document.create_sample_document
d_v2 = d.versions.last.reify(:has_many => true)

last line fails with the below. Happy to provide more info/test, let me know what is needed.

NoMethodError: undefined method section_id' for #<Section:0x00000001566318> from /home/andre/.rvm/gems/ruby-2.1.2/gems/activemodel-4.2.3/lib/active_model/attribute_methods.rb:433:inmethod_missing'
from /home/andre/.rvm/gems/ruby-2.1.2/gems/paper_trail-4.0.0/lib/paper_trail/version_concern.rb:394:in block (2 levels) in reify_has_many_through' from /home/andre/.rvm/gems/ruby-2.1.2/gems/activerecord-4.2.3/lib/active_record/relation/delegation.rb:46:inmap'
from /home/andre/.rvm/gems/ruby-2.1.2/gems/activerecord-4.2.3/lib/active_record/relation/delegation.rb:46:in map' from /home/andre/.rvm/gems/ruby-2.1.2/gems/paper_trail-4.0.0/lib/paper_trail/version_concern.rb:394:inblock in reify_has_many_through'
from /home/andre/.rvm/gems/ruby-2.1.2/gems/paper_trail-4.0.0/lib/paper_trail/version_concern.rb:391:in each' from /home/andre/.rvm/gems/ruby-2.1.2/gems/paper_trail-4.0.0/lib/paper_trail/version_concern.rb:391:inreify_has_many_through'
from /home/andre/.rvm/gems/ruby-2.1.2/gems/paper_trail-4.0.0/lib/paper_trail/version_concern.rb:347:in reify_has_manys' from /home/andre/.rvm/gems/ruby-2.1.2/gems/paper_trail-4.0.0/lib/paper_trail/version_concern.rb:232:inblock in reify'
from /home/andre/.rvm/gems/ruby-2.1.2/gems/paper_trail-4.0.0/lib/paper_trail/version_concern.rb:303:in call' from /home/andre/.rvm/gems/ruby-2.1.2/gems/paper_trail-4.0.0/lib/paper_trail/version_concern.rb:303:inwithout_identity_map'
from /home/andre/.rvm/gems/ruby-2.1.2/gems/paper_trail-4.0.0/lib/paper_trail/version_concern.rb:168:in reify' from (irb):3 from /home/andre/.rvm/gems/ruby-2.1.2/gems/railties-4.2.3/lib/rails/commands/console.rb:110:instart'
from /home/andre/.rvm/gems/ruby-2.1.2/gems/railties-4.2.3/lib/rails/commands/console.rb:9:in start' from /home/andre/.rvm/gems/ruby-2.1.2/gems/railties-4.2.3/lib/rails/commands/commands_tasks.rb:68:inconsole'
from /home/andre/.rvm/gems/ruby-2.1.2/gems/railties-4.2.3/lib/rails/commands/commands_tasks.rb:39:in run_command!' from /home/andre/.rvm/gems/ruby-2.1.2/gems/railties-4.2.3/lib/rails/commands.rb:17:in<top (required)>'

[allavena]

If I merely remove the has_many :paragraphs, through: :sections from document, then it no longer crashes in console - this is something I'm happy to leave for my app.

Difference between test and dev environment is still there. I've sent you another pull request for a simpler case (no paragraphs) which still shows the children missing on a previous version in test environment.

[jaredbeck]

Difference between test and dev environment is still there.

Yes, it's not currently possible to test reification of associations when use_transactional_fixtures = true. This is a known issue: #542

Regarding the NoMethodError ..

NoMethodError: undefined method `section_id' for #Section:0x00000006c6ad58

By setting use_transactional_fixtures = false, I've reproduced this error in the test app we've been working on (https://github.com/jaredbeck/pt_issue_590) with a failing test.

If I merely remove the has_many :paragraphs, through: :sections from document, then it no longer crashes in console - this is something I'm happy to leave for my app.

I'm glad that workaround is OK for you, but I believe it is our goal to support has_many through, and you shouldn't have to do that. I'll mark this as a confirmed bug. Thanks for reporting it!

[jaredbeck]

I've added a warning to the readme: ce37034

[theRealNG]

The issue is at this line: https://github.com/airblade/paper_trail/blob/master/lib/paper_trail/version_concern.rb#L420

collection_keys should collect the list of all the records that are associated with has_many through relationship. ( The present code only works for belongs_to association).

Fixed the issue in theRealNG@5bcfb86

Will test it throughly and place a pull request

[jaredbeck]

Fixed by #596, closing.

[bdelmas]

Is it really fixed? I came across this. Maybe we can delete it from the known issue if it is?

[jaredbeck]

Is it really fixed? I came across this. Maybe we can delete it from the known issue if it is?

Hi Benjamin. This issue (#590) was fixed by #596 and released in PT 4.1.0. You are looking at the docs for 4.0. The docs for 4.1 (https://github.com/airblade/paper_trail/blob/4.1-stable/README.md) do not mention #590.

[bdelmas]

Hi Jared. Ah ok, thanks for your answer! I still have problems with associations with the 4.1.0 and the master version. If I can pin down the problem I will post an issue.