Feature Request: Error if content_for called from within fragment cache

[mipearson]

It is very easy to accidentally call content_for from within a block that will be fragment cached, especially if the cached fragment calls out to a partial. eg:

<!--  index.html.erb -->
<%= cache "fragment" do %>
  <!-- ... -->
  <%= render "javascript_widget" %>
<% end %>
<!-- load javascript files last -->
<%= content_for :javascript_includes %>

<!--- _javascript_widget.html.erb -->
<div class="jsPlaceholder />
<% content_for :javascript_includes do %>
  <%= javascript_inlcude_tag ... %>
<% end %>

Steps to reproduce

Call content_for from within code that will end up in a fragment cache

Expected behavior

An error should be raised letting the developer know that the content_for would not occur.

Actual behavior

The contents of the content_for are silently discarded.

System configuration

Rails 5.0.1, Ruby 2.3.1

[st0012]

I think feature request should be posted in mailing list?

[maclover7]

Agree with @st0012. Please use the mailing list for feature requests, where a wider community will be able to help you. We reserve the issues tracker for issues only.

[mipearson]

No problem, will do.