Ensure @content_for_* is checked before yielding to block in render :layout [#8994 state:resolved]

Signed-off-by: NJoshua Peek <josh@joshpeek.com>

actionpack/lib/action_view/renderable.rb

@@ -36,7 +36,7 @@ def render(view, local_assigns = {})
 
       result = view.send(method_name(local_assigns), local_assigns) do |*names|
         ivar = :@_proc_for_layout
-        if view.instance_variable_defined?(ivar) and proc = view.instance_variable_get(ivar)
+        if !view.instance_variable_defined?(:"@content_for_#{names.first}") && view.instance_variable_defined?(ivar) && (proc = view.instance_variable_get(ivar))
           view.capture(*names, &proc)
         elsif view.instance_variable_defined?(ivar = :"@content_for_#{names.first || :layout}")
           view.instance_variable_get(ivar)

actionpack/test/fixtures/layouts/_column.html.erb

+<div id="column"><%= yield :column %></div>
+<div id="content"><%= yield %></div>
\ No newline at end of file

actionpack/test/fixtures/test/nested_layout.erb

+<% content_for :title, "title" -%>
+<% content_for :column do -%>column<% end -%>
+<% render :layout => 'layouts/column' do -%>content<% end -%>
\ No newline at end of file

actionpack/test/template/render_test.rb

@@ -162,4 +162,14 @@ def test_render_inline_with_locals_and_compilable_custom_type
     ActionView::Template.register_template_handler :foo, CustomHandler
     assert_equal 'source: "Hello, <%= name %>!"', @view.render(:inline => "Hello, <%= name %>!", :locals => { :name => "Josh" }, :type => :foo)
   end
+
+  def test_render_with_layout
+    assert_equal %(<title></title>\nHello world!\n),
+      @view.render(:file => "test/hello_world.erb", :layout => "layouts/yield")
+  end
+
+  def test_render_with_nested_layout
+    assert_equal %(<title>title</title>\n<div id="column">column</div>\n<div id="content">content</div>\n),
+      @view.render(:file => "test/nested_layout.erb", :layout => "layouts/yield")
+  end
 end