Updating counts in response to changes in middle of relation chain

[DavidMikeSimon]

At the moment, it seems that counter_culture does not notice changes that happen on models in the middle of multi-level counter caches. For example, I added this code to the end of the "updates third-level counter cache on update" test, but it failed:

company2.industry_id = industry1.id
company2.save!

industry1.reload
industry2.reload

industry1.reviews_count.should == 69
industry2.reviews_count.should == 0

[magnusvk]

Yeah, I think you've hit on a real bug here. I don't think there's any handling on the models in the middle of a chain. Kind of surprising this hasn't come up before, actually. 😄

I can't promise I'll find the time to work on this anytime soon. But I'd be very happy to review a PR if you found the time.

Thanks for reporting this.

[QuotableWater7]

fwiw, we actually ran into this issue about 9 mo ago and resorted to a heavy-handed counting approach since I wasn't sure there was an easy way to handle the situation. If I find the time, I'll take a look at the code and see if I can figure out a reasonable approach

[SakthiGurunathan07]

Hi @magnusvk
Whether this issue is fixed or can u help us with some approach on how to fix this ?

Thanks,
Sakthi

[magnusvk]

@SakthiGurunathan07 This is not fixed. Feel free to work on a PR here, I haven't had the time to work on a fix unfortunately.

[pedantic-git]

Oooof - just had a go at fixing this but it's hard. counter_culture tracks changes by inserting callbacks into the model that contains the counter_culture directive, but in order to do this, callbacks would have to be inserted into the intermediate models using reflection. I'm not sure it's easy to solve without a big rewrite of some of the core functionality. @magnusvk would you agree?

[magnusvk]

Yeah, unfortunately that sounds right.

[lukaszludzik]

This is not perfect solution, but works. If you want to count products for categories you must also count for subcategories.

class Product < ActiveRecord::Base
  belongs_to :sub_category
  counter_culture :sub_category
  counter_culture [:sub_category, :category]
end

class SubCategory < ActiveRecord::Base
  has_many :products
  belongs_to :category
  counter_culture :category, column_name: 'products_count', delta_magnitude: proc { 
    |sub_category| sub_category.products_count }
end

class Category < ActiveRecord::Base
  has_many :sub_categories
end

[sebastienhoorens]

We tried @lukaszludzik 's solution but it didn't work in our case. We will try to solve it using callbacks on the model.