&block rendered twice or at the wrong position from helper

[mdrbohlav]

I have a custom form builder but since I want to be able to use the default one as well I created helper method for it:

# form_helper.rb

module FormHelper
  def my_form_with(**args, &block)
    form_with(builder: MyFormBuilder, **args, &block)
  end
end

And when I try to use it inside any component I get two different results but neither of them is what I expect it to be. One renders the block twice - before and inside the form tag. The other one renders the block only before the form tag.

Note that when I use the form_with directly in the component's template it works so this has something to do with it being called from the helper.

Steps to reproduce

Create helper that receives &block, pass that block to any rails helper like form_with, link_to, etc. Use the created helper in the component.

Expected behavior

It should render the block inside the form tag and only once. The same way it works when used outside the component

Actual behavior

Example 1:

# component.html.erb

<%= helpers.my_form_with do %>
  Example string
<% end>

Result:

Example string

<form action="..." method="post">
    Example string
</form>

Example 2:

# component.html.erb

<%= helpers.my_form_with(model: Model) do |form| %>
  <% form.text_field(:title) %>
<% end>

Result:

<input id="model_title" type="text" name="model[title]">

<form action="..." method="post">
</form>

System configuration

Rails version: 6.1

Ruby version: 2.7.6

Gem version: 2.56.2

[Spone]

See #974 for the WIP on this issue 🙂

[mdrbohlav]

I have found some issues with the similar problem but totally missed the PR, thank you!

[hulloitskai]

I believe that another PR aimed to resolve this issue was actually merged (#1307), and then subsequently reverted: #1432.

I've recently run into this issue, and I was wondering if there are any efforts being made to address it, now that we are no longer experimenting with a single output buffer.