Cache key should be different when is Array.

`cache.fetch(['foo'])` and `cache.fetch('foo')` should generate
different cache keys as they are not equivalents.

[related #8615]
[related #8614]

1 files changed, 4 insertions, 3 deletions

diff --git a/activesupport/lib/active_support/cache.rb b/activesupport/lib/active_support/cache.rb
index a627fa8651..f23f6f16d6 100644
--- a/activesupport/lib/active_support/cache.rb
+++ b/activesupport/lib/active_support/cache.rb
@@ -511,7 +511,7 @@ module ActiveSupport
         # called. If the key is a Hash, then keys will be sorted alphabetically.
         def expanded_key(key) # :nodoc:
           return key.cache_key.to_s if key.respond_to?(:cache_key)
-
+          trailing_slash = false
           case key
           when Array
             if key.size > 1
@@ -519,11 +519,12 @@ module ActiveSupport
             else
               key = key.first
             end
+            trailing_slash = true
           when Hash
             key = key.sort_by { |k,_| k.to_s }.collect{|k,v| "#{k}=#{v}"}
           end
-
-          key.to_param
+          key = key.to_param
+          trailing_slash ? "#{key}/" : key
         end
 
         # Prefix a key with the namespace. Namespace and key will be delimited