[WIP] When a record is deleted it should use unscoped association calls

[vkmita]

@libo @dasch @bquorning @pdeuter

I think this addition is useful, for example, you can retrieve a deleted category, and gracefully get the default_translation without having to do something like this:

>> DC::Content.with_deleted { DC::Translation.with_deleted { category.default_translation.title } }
  DC::Content Load (0.2ms)  SELECT `dc_contents`.* FROM `dc_contents` WHERE `dc_contents`.`source_id` = 10017 AND `dc_contents`.`source_type` = 'Category' LIMIT 1
  DC::Translation Load (0.3ms)  SELECT `dc_translations`.* FROM `dc_translations` WHERE `dc_translations`.`id` = 10112 LIMIT 1
=> "Using Help Center"

Instead we can simply do:

>> category.default_translation.title
  DC::Content Load (0.2ms)  SELECT `dc_contents`.* FROM `dc_contents` WHERE `dc_contents`.`source_id` = 10017 AND `dc_contents`.`source_type` = 'Category' LIMIT 1
  DC::Translation Load (0.3ms)  SELECT `dc_translations`.* FROM `dc_translations` WHERE `dc_translations`.`id` = 10112 LIMIT 1
=> "Using Help Center"

The thing I'm having trouble with is the timing of redefining the association methods. If I do a class_eval at the time the module is included it doesn't work because it seems like Rails is redefining the has_many associations after I initially redefine them. The only solution I came up with for that was overriding the methods in an after_initialize callback, and simply marking which classes were overridden so we don't do it twice.

What do you guys think?

[vkmita]

Hmm I just saw #3 I think my approach still works with Rails4??

[dasch]

This is updating global state :-/ I'm not quite sure what this is supposed to do – do you want to track which AR classes include Restorable? If so, there are simpler ways of doing it.

[vkmita]

I had trouble tapping into the a time after AR defined the association methods. My solution was to do it in an after_initialize callback because I knew AR wouldn't redefine them again at that point. And because I don't want to redefine the association methods after each initialization, I kept track of the classes where I redefined the.

Does that make sense?

[dasch]

@vkmita can you rebase this on master?

[pdeuter]

hi @dasch ... we cannot rely on @vkmita to work further on this PR. Victor is working on another team now.
This PR really needs your expertise. Can you take over this PR?