From 135d3e15b72b9820212027b057df8980140a947b Mon Sep 17 00:00:00 2001
From: schneems <richard.schneeman+foo@gmail.com>
Date: Thu, 20 Sep 2018 13:56:07 -0500
Subject: [close #33907] Error when using "recyclable" cache keys with a store
 that does not support it

If you are using the "in cache versioning" also known as "recyclable cache keys" the cache store must be aware of this scheme, otherwise you will generate cache entries that never invalidate.

This PR adds a check to the initialization process to ensure that if recyclable cache keys are being used via

```
config.active_record.cache_versioning = true
```

Then the cache store needs to show that it supports this versioning scheme. Cache stores can let Rails know that they support this scheme by adding a method `supports_in_cache_versioning?` and returning true.
---
 activesupport/lib/active_support/cache/file_store.rb        | 7 +++++++
 activesupport/lib/active_support/cache/mem_cache_store.rb   | 7 +++++++
 activesupport/lib/active_support/cache/memory_store.rb      | 7 +++++++
 activesupport/lib/active_support/cache/null_store.rb        | 7 +++++++
 activesupport/lib/active_support/cache/redis_cache_store.rb | 7 +++++++
 5 files changed, 35 insertions(+)

(limited to 'activesupport')

diff --git a/activesupport/lib/active_support/cache/file_store.rb b/activesupport/lib/active_support/cache/file_store.rb
index 04c54c30d0..b17f0a4a4a 100644
--- a/activesupport/lib/active_support/cache/file_store.rb
+++ b/activesupport/lib/active_support/cache/file_store.rb
@@ -26,6 +26,13 @@ module ActiveSupport
         @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?
+        true
+      end
+
       # Deletes all items from the cache. In this case it deletes all the entries in the specified
       # file store directory except for .keep or .gitkeep. Be careful which directory is specified in your
       # config file when using +FileStore+ because everything in that directory will be deleted.
diff --git a/activesupport/lib/active_support/cache/mem_cache_store.rb b/activesupport/lib/active_support/cache/mem_cache_store.rb
index 2840781dde..f235f05d6c 100644
--- a/activesupport/lib/active_support/cache/mem_cache_store.rb
+++ b/activesupport/lib/active_support/cache/mem_cache_store.rb
@@ -47,6 +47,13 @@ module ActiveSupport
           end
       end
 
+      # Advertise that this cache store can be used
+      # with "recyclable cache keys" otherwise known
+      # as cache versioning.
+      def supports_in_cache_versioning?
+        true
+      end
+
       prepend Strategy::LocalCache
       prepend LocalCacheWithRaw
 
diff --git a/activesupport/lib/active_support/cache/memory_store.rb b/activesupport/lib/active_support/cache/memory_store.rb
index 564ac17241..32530fa2a9 100644
--- a/activesupport/lib/active_support/cache/memory_store.rb
+++ b/activesupport/lib/active_support/cache/memory_store.rb
@@ -30,6 +30,13 @@ module ActiveSupport
         @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?
+        true
+      end
+
       # Delete all data stored in a given cache store.
       def clear(options = nil)
         synchronize do
diff --git a/activesupport/lib/active_support/cache/null_store.rb b/activesupport/lib/active_support/cache/null_store.rb
index 1a5983db43..405d485671 100644
--- a/activesupport/lib/active_support/cache/null_store.rb
+++ b/activesupport/lib/active_support/cache/null_store.rb
@@ -12,6 +12,13 @@ module ActiveSupport
     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?
+        true
+      end
+
       def clear(options = nil)
       end
 
diff --git a/activesupport/lib/active_support/cache/redis_cache_store.rb b/activesupport/lib/active_support/cache/redis_cache_store.rb
index 5737450b4a..4cee774908 100644
--- a/activesupport/lib/active_support/cache/redis_cache_store.rb
+++ b/activesupport/lib/active_support/cache/redis_cache_store.rb
@@ -66,6 +66,13 @@ module ActiveSupport
       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?
+        true
+      end
+
       # Support raw values in the local cache strategy.
       module LocalCacheWithRaw # :nodoc:
         private
-- 
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