Unable to render layouts when using inline turbo stream responses

[spohlenz]

I've found an inconsistency with the rendering of layouts and inline turbo stream responses, with the combination of the two currently being broken.

When rendering a turbo stream template action.turbo_stream.erb, it is rendered within a layout (e.g. application.turbo_stream.erb) if available. However when using render turbo_stream: turbo_stream.etc..., no layout is used. Furthermore, it is not possible to force a layout to be used by passing layout: true or layout: "application".

class TestController < ApplicationController
  def turbo_template
    # Renders template with application layout
  end

  def turbo_template_layout_true
    # Renders template with application layout
    render layout: true
  end

  def turbo_inline
    # Renders with no layout
    render turbo_stream: turbo_stream.append("container") { "Hello from inline Turbo Stream" }
  end

  def turbo_inline_layout_true
    # Renders with no layout (!)
    render turbo_stream: turbo_stream.append("container") { "Hello from inline Turbo Stream (layout: true)" }, layout: true
  end

  def turbo_inline_explicit_layout
    # Renders with no layout (!)
    render turbo_stream: turbo_stream.append("container") { "Hello from inline Turbo Stream (explicit layout)" }, layout: "application"
  end
end

I have created an example repo at https://github.com/spohlenz/turbo-stream-layouts (with the relevant changes in spohlenz/turbo-stream-layouts#8afd217d005f2f852bf27fb871ac4bbf7291d72a). This example uses Rails 7.2.0.beta3 and turbo-rails 2.0.6 but I have seen the same behavior on earlier Rails versions.

[4lllex]

You could override :turbo_stream renderer if you really need this:

# config/initializers/turbo_layout.rb

# on load hook is to make sure to load this after Turbo adds its renderer
ActiveSupport.on_load(:action_controller) do
  ActionController::Renderers.add :turbo_stream do |source, options|
    self.content_type = Mime[:turbo_stream] if media_type.nil?
    render_to_string(inline: source, layout: options[:layout])
  end
end