Rails 6 ActionView::MissingTemplate Missing template errors/500

I am working on to upgrade existing project and upgrade version from ruby 2.3.1 to version to 3.0.1 (rails 6.1.4) with related gems.

After uploading image, when execute render json, generate error for missing template.


assets =>
0 => #<ActionDispatch::Http::UploadedFile:0x000000000ce165c0>
()    *Cookies:* *_{"session_id"=>"52d50d...", "profilin"=>"p=t...", "CloudFront-Policy"=>"eyJTdG...", "CloudFront-Signature"=>"TSA9KD...", "CloudFront-Key-Pair-Id"=>"ABBABB...", "ga"=>"GA1.2....", "gid"=>"GA1.2....", "gat"=>"1..."}_*
()    *Exception Message:*
ActionView::MissingTemplate Missing template errors/500, application/500 with {:locale=>[:en], :formats=>[:json], :variants=>[], :handlers=>[:raw, :erb, :html, :builder, :ruby, :coffee, :mustache]}. Searched in:
  * "/media/test/DATA/userdrive/tube/app/views"
  * "/home/test/.rvm/gems/ruby-3.0.1/gems/actiontext-6.1.4/app/views"
  * "/home/test/.rvm/gems/ruby-3.0.1/gems/actionmailbox-6.1.4/app/views"


render json: { 
  assets: new_assets_list.map { 
    |asset| (asset.nil? ? nil : view_context.asset_for_mustache(asset, @parent, nil, false)) 
 }, error_asset_arr: error_asset_list_arr }, status: 200

Where: view_context.asset_for_mustache is a function to return object value and working properly.

We have used paperclip (now kt-paperclip) for file upload on s3 bucket. (as of now, we don’t want to change to ActiveStorage) After creating new assets when try to render with render json, throws the error.

Any suggestion, how to solve the issue? or where need to check?

Hey there!

Thanks for posting your comment, is there any chance you can share an example application on GitHub to demonstrate the issue you are facing, that will make it a little easier to help track down what’s going wrong :slightly_smiling_face: