Make collection caching explicit.

Having collection caching that wraps templates and automatically tries
to infer if they are cachable proved to be too much of a hassle.

We'd rather have it be something you explicitly turn on.

This removes much of the code and docs to explain the previous automatic
behavior.

This change also removes scoped cache keys and passing cache_options.

1 files changed, 11 insertions, 26 deletions

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 4860f00243..debfcae870 100644
--- a/actionview/lib/action_view/renderer/partial_renderer/collection_caching.rb
+++ b/actionview/lib/action_view/renderer/partial_renderer/collection_caching.rb
@@ -1,5 +1,3 @@
-require 'active_support/core_ext/object/try'
-
 module ActionView
   module CollectionCaching # :nodoc:
     extend ActiveSupport::Concern
@@ -12,7 +10,7 @@ module ActionView
 
     private
       def cache_collection_render
-        return yield unless cache_collection?
+        return yield unless @options[:cached]
 
         keyed_collection = collection_by_cache_keys
         cached_partials = collection_cache.read_multi(*keyed_collection.keys)
@@ -21,30 +19,14 @@ module ActionView
         rendered_partials = @collection.empty? ? [] : yield
 
         index = 0
-        keyed_collection.map do |cache_key, _|
-          cached_partials.fetch(cache_key) do
-            rendered_partials[index].tap { index += 1 }
-          end
+        fetch_or_cache_partial(cached_partials, order_by: keyed_collection.each_key) do
+          rendered_partials[index].tap { index += 1 }
         end
       end
 
-      def cache_collection?
-        @options.fetch(:cache, automatic_cache_eligible?)
-      end
-
-      def automatic_cache_eligible?
-        @template && @template.eligible_for_collection_caching?(as: @options[:as])
-      end
-
-      def callable_cache_key?
-        @options[:cache].respond_to?(:call)
-      end
-
       def collection_by_cache_keys
-        seed = callable_cache_key? ? @options[:cache] : ->(i) { i }
-
         @collection.each_with_object({}) do |item, hash|
-          hash[expanded_cache_key(seed.call(item))] = item
+          hash[expanded_cache_key(item)] = item
         end
       end
 
@@ -53,10 +35,13 @@ module ActionView
         key.frozen? ? key.dup : key # #read_multi & #write may require mutability, Dalli 2.6.0.
       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])
+      def fetch_or_cache_partial(cached_partials, order_by:)
+        order_by.map do |cache_key|
+          cached_partials.fetch(cache_key) do
+            yield.tap do |rendered_partial|
+              collection_cache.write(cache_key, rendered_partial)
+            end
+          end
         end
       end
   end