Do not retrieve disabled versions

[filipegiusti]

Fixes #1350 (copy from it's content below)

The code speaks for itself

require 'carrierwave'

class BugUploader < CarrierWave::Uploader::Base
  version :thumb, if: :always_false do
    def default_url
      'default.png'
    end
  end

  def root
    '~'
  end

  def always_false(*args)
    false
  end
end

up1 = BugUploader.new
up1.store!(File.open(__FILE__))
puts up1.thumb.url
# default.png

up2 = BugUploader.new
up2.retrieve_from_store!('lalala.png')
puts up2.thumb.url
# /uploads/thumb_lalala.png

[bensie]

@filipegiusti We need to ensure that files are never orphaned. The current implementation of conditional versions is more about the save process and less about URL fetching, where versions are processed conditionally at that time. At a later time, this condition may be different but the file may still be on disk.

[filipegiusti]

I understand what you're saying. We can comply to both, on removal we can try to destroy all versions if it doesn't exist it will silently fail and we won't have orphans, and on retrieval we only get the ones that the conditional succeeds. Wdyt?

[filipegiusti]

@bensie I've update the code to comply with your requirements, I don't see any downside in merging it as is.

[filipegiusti]

Anyone listening? ⏰

[bensie]

@filipegiusti Sorry it's been so long! Would you mind rebasing off master so we can merge?

[filipegiusti]

I'll do that next week!

[bensie]

I went ahead and got it merged, thanks!

[filipegiusti]

Awesome, thanks!