Add support for expires_in: when using render with collection:

- Pass `expires_in:` to `write_multi` so the cache key is written with the expiration.
- Added test.
- Added documentation.

actionview/CHANGELOG.md

@@ -1,3 +1,7 @@
+*   Add `expires_in:` option to `render` when used with `collection:`
+
+    *Jarrett Lusso*
+
 *   Add queries count to template rendering instrumentation
 
     ```

actionview/lib/action_view/renderer/partial_renderer/collection_caching.rb

@@ -111,7 +111,7 @@ def fetch_or_cache_partial(cached_partials, template, order_by:)
         end
 
         unless entries_to_write.empty?
-          collection_cache.write_multi(entries_to_write)
+          collection_cache.write_multi(entries_to_write, @options.slice(:expires_in))
         end
 
         keyed_partials

actionview/test/template/render_test.rb

@@ -936,6 +936,17 @@ class CachedCustomer < Customer; end
     assert_equal "Hello: david", ActionView::PartialRenderer.collection_cache.read(key)
   end
 
+  test "template body written to cache with expiration when expires_in set" do
+    customer = Customer.new("jarrett", 2)
+    key = cache_key(customer, "test/_customer")
+    assert_nil ActionView::PartialRenderer.collection_cache.read(key)
+    @view.render(partial: "test/customer", collection: [customer], cached: true, expires_in: 1.hour)
+    assert_equal "Hello: jarrett", ActionView::PartialRenderer.collection_cache.read(key)
+    cache_data = ActionView::PartialRenderer.collection_cache.instance_variable_get('@data')
+    cache_key = cache_data.detect { |k, _v| k.include?('jarrett') }.last
+    assert cache_key.expires_at.present?
+  end
+
   test "collection caching does not cache by default" do
     customer = Customer.new("david", 1)
     key = cache_key(customer, "test/_customer")

guides/source/caching_with_rails.md

@@ -132,6 +132,15 @@ do not overwrite each other:
            cached: ->(product) { [I18n.locale, product] } %>
 ```
 
+Additionally, you can configure `expires_in` to explicitly set the expiration.
+
+```html+erb
+<%= render partial: 'products/product',
+           collection: @products,
+           cached: true,
+           expires_in: 1.hour %>
+```
+
 ### Russian Doll Caching
 
 You may want to nest cached fragments inside other cached fragments. This is