Fog (AWS S3) file read throws an inappropriate error if file doesn't exist

[AnrichVS]

When CarrierWave::Storage::Fog::File#read is called on a file that doesn't exist (specifically on AWS S3 in this case), the following error is thrown:

NoMethodError: undefined method `body' for nil:NilClass

This occurs here - carrierwave-2.1.0/lib/carrierwave/storage/fog.rb:298

297        def read
298          file_body = file.body
299
300          return if file_body.nil?

This is because fileis nil. This is to be expected if the remote file doesn't exist, as per the Fog::AWS::Storage::Files#head method in fog-aws-3.7.0/lib/fog/aws/models/storage/files.rb:99

        def head(key, options = {})
          requires :directory
          data = service.head_object(directory.key, key, options)
          normalize_headers(data)
          file_data = data.headers.merge({
            :key => key
          })
          new(file_data)
        rescue Excon::Errors::NotFound
          nil
        end

The rescue triggers if the remote file doesn't exist, which returns nil.

The CarrierWave::Storage::Fog::File#read method should probably be:

297        def read
298          file_body = file&.body
299
300          return if file_body.nil?