Write to collection cache where the template is rendered.

Moves us closer to having access to a local template variable,
we can ask for eligibility and its virtual_path.

Currently we rely on `@template`, which we don't have available
when rendering collections without a fixed template.

2 files changed, 15 insertions, 9 deletions

diff --git a/actionview/lib/action_view/renderer/partial_renderer.rb b/actionview/lib/action_view/renderer/partial_renderer.rb
index bdbf03191a..a9bd257e76 100644
--- a/actionview/lib/action_view/renderer/partial_renderer.rb
+++ b/actionview/lib/action_view/renderer/partial_renderer.rb
@@ -428,6 +428,8 @@ module ActionView
         layout = find_template(layout, @template_keys)
       end
 
+      collection_cache_eligible = automatic_cache_eligible?
+
       partial_iteration = PartialIteration.new(@collection.size)
       locals[iteration] = partial_iteration
 
@@ -436,6 +438,11 @@ module ActionView
         locals[counter]   = partial_iteration.index
 
         content = template.render(view, locals)
+
+        if collection_cache_eligible
+          collection_cache_rendered_partial(content, object)
+        end
+
         content = layout.render(view, locals) { content } if layout
         partial_iteration.iterate!
         content
diff --git a/actionview/lib/action_view/renderer/partial_renderer/collection_caching.rb b/actionview/lib/action_view/renderer/partial_renderer/collection_caching.rb
index c353eb0b31..a037424498 100644
--- a/actionview/lib/action_view/renderer/partial_renderer/collection_caching.rb
+++ b/actionview/lib/action_view/renderer/partial_renderer/collection_caching.rb
@@ -51,16 +51,15 @@ module ActionView
       end
 
       def fetch_or_cache_partial(cached_partials, order_by:)
-        rely_on_individual_cache_call = !callable_cache_key?
-
         order_by.map do |key|
-          cached_partials.fetch(key) do
-            yield.tap do |rendered_partial|
-              unless rely_on_individual_cache_call
-                collection_cache.write(key, rendered_partial, @options[:cache_options])
-              end
-            end
-          end
+          cached_partials.fetch(key) { yield }
+        end
+      end
+
+      def collection_cache_rendered_partial(rendered_partial, key_by)
+        if callable_cache_key?
+          key = expanded_cache_key(@options[:cache].call(key_by))
+          collection_cache.write(key, rendered_partial, @options[:cache_options])
         end
       end
   end