Switch to supports_cache_versioning? check to a class method

- Moving the `supports_cache_versioning?` check to a class method. 
- Shorten the method doc. 
- Expand on the error message.

Author: schneems

activerecord/lib/active_record/railtie.rb

@@ -92,17 +92,19 @@ class Railtie < Rails::Railtie # :nodoc:
       config.after_initialize do |app|
         ActiveSupport.on_load(:active_record) do
           if app.config.active_record.cache_versioning && Rails.cache
-            unless Rails.cache.try(:supports_in_cache_versioning?)
+            unless Rails.cache.class.try(:supports_cache_versioning?)
               raise <<-end_error
 
-You're using a cache store `#{Rails.cache.class}` that does not support
-"recyclable" cache keys, also known as "in cache versioning". To
-fix this issue either disable "recyclable" cache keys by setting:
+You're using a cache store that doesn't support native cache versioning.
+Your best option is to upgrade to a newer version of #{Rails.cache.class}
+that supports cache versioning (#{Rails.cache.class}.supports_cache_versioning? #=> true).
 
-    config.active_record.cache_versioning = false
+Next best, switch to a different cache store that does support cache versioning:
+https://guides.rubyonrails.org/caching_with_rails.html#cache-stores.
+
+To keep using the current cache store, you can turn off cache versioning entirely:
 
-Or switching to a cache store that supports this functionality:
-https://guides.rubyonrails.org/caching_with_rails.html#cache-stores
+    config.active_record.cache_versioning = false
 
 end_error
             end

activesupport/lib/active_support/cache/file_store.rb

@@ -26,10 +26,8 @@ def initialize(cache_path, options = nil)
         @cache_path = cache_path.to_s
       end
 
-      # Advertise that this cache store can be used
-      # with "recyclable cache keys" otherwise known
-      # as cache versioning.
-      def supports_in_cache_versioning?
+      # Advertise cache versioning support.
+      def self.supports_cache_versioning?
         true
       end
 

activesupport/lib/active_support/cache/mem_cache_store.rb

@@ -47,10 +47,8 @@ def write_entry(key, entry, options)
           end
       end
 
-      # Advertise that this cache store can be used
-      # with "recyclable cache keys" otherwise known
-      # as cache versioning.
-      def supports_in_cache_versioning?
+      # Advertise cache versioning support.
+      def self.supports_cache_versioning?
         true
       end
 

activesupport/lib/active_support/cache/memory_store.rb

@@ -30,10 +30,8 @@ def initialize(options = nil)
         @pruning = false
       end
 
-      # Advertise that this cache store can be used
-      # with "recyclable cache keys" otherwise known
-      # as cache versioning.
-      def supports_in_cache_versioning?
+      # Advertise cache versioning support.
+      def self.supports_cache_versioning?
         true
       end
 

activesupport/lib/active_support/cache/null_store.rb

@@ -12,10 +12,8 @@ module Cache
     class NullStore < Store
       prepend Strategy::LocalCache
 
-      # Advertise that this cache store can be used
-      # with "recyclable cache keys" otherwise known
-      # as cache versioning.
-      def supports_in_cache_versioning?
+      # Advertise cache versioning support.
+      def self.supports_cache_versioning?
         true
       end
 

activesupport/lib/active_support/cache/redis_cache_store.rb

@@ -66,10 +66,8 @@ class RedisCacheStore < Store
       SCAN_BATCH_SIZE = 1000
       private_constant :SCAN_BATCH_SIZE
 
-      # Advertise that this cache store can be used
-      # with "recyclable cache keys" otherwise known
-      # as cache versioning.
-      def supports_in_cache_versioning?
+      # Advertise cache versioning support.
+      def self.supports_cache_versioning?
         true
       end
 

railties/CHANGELOG.md

@@ -1,5 +1,7 @@
 *   Raise an error when "recyclable cache keys" are being used by a cache store
-    that does not explicitly support it.
+    that does not explicitly support it. Custom cache keys that do support this feature
+    can bypass this error by implementing the `supports_cache_versioning?` method on their
+    class and returning a truthy value.
 
     *Richard Schneeman*
 

railties/test/application/configuration_test.rb

@@ -133,7 +133,7 @@ class MyLogger < ::Logger
         app "production"
       end
 
-      assert_match(/You're using a cache store/, error.message)
+      assert_match(/You're using a cache/, error.message)
     end
 
     test "a renders exception on pending migration" do