Can't get form_with to work from a cell in Rails 6

[marnen]

I just tried to use Cells with a Rails 6 application, and failed when trying to generate a (non-model-based) form. Even though I included ActionView::Helpers::FormHelper into the cell, form_with (and form_tag) always failed with NoMethodError: undefined method `[]' for nil:NilClass. Any ideas as to how to get this to work?

[apotonick]

Hi @marnen, you need to use the cells-rails gem. https://github.com/trailblazer/cells-rails/

http://trailblazer.to/gems/cells/rails.html

[marnen]

@apotonick i did use cells-rails when I had the problem. I can file an issue there if it would be better.

[marnen]

I think I figured out the issue. I used new instead of the cell helper method to render the cell, so cells-rails didn't get a chance to set up the context properly. Once I used the cell helper, everything worked. Leaving this open only because it might be worth documenting this gotcha.