Bound native fragment caching and collapse concurrent page renders

config/initializers/fragment_cache.rb

@@ -0,0 +1,24 @@
+require "jbuilder/jbuilder_template"
+
+# Jbuilder 2.14.1 uses Rails.cache directly; use the same bounded store as ERB
+# while retaining its native keys and controller instrumentation.
+module BoundedJbuilderFragments
+  private
+    def _read_fragment_cache(key, options = nil)
+      @context.controller.instrument_fragment_cache :read_fragment, key do
+        @context.controller.cache_store.read(key, options)
+      end
+    end
+
+    def _write_fragment_cache(key, options = nil)
+      @context.controller.instrument_fragment_cache :write_fragment, key do
+        yield.tap { |value| @context.controller.cache_store.write(key, value, options) }
+      end
+    end
+end
+
+JbuilderTemplate.prepend(BoundedJbuilderFragments)
+
+Rails.application.config.to_prepare do
+  ActionView::PartialRenderer.collection_cache = FragmentCache.store
+end