Don't include ellipsis in truncated digest output

Using `truncate` to limit the length of the digest has the unwanted side
effect of adding an ellipsis when the input is longer than the limit.

Also:
 - Don't instantiate a new object for every digest
 - Rename the configuration option to `hash_digest_class`
 - Update the CHANGELOG entry to describe how to use the feature

1 files changed, 1 insertions, 9 deletions

diff --git a/activesupport/lib/active_support/digest.rb b/activesupport/lib/active_support/digest.rb
index d77eeb072b..fba10fbdcf 100644
--- a/activesupport/lib/active_support/digest.rb
+++ b/activesupport/lib/active_support/digest.rb
@@ -13,16 +13,8 @@ module ActiveSupport
       end
 
       def hexdigest(arg)
-        new.hexdigest(arg)
+        hash_digest_class.hexdigest(arg)[0...32]
       end
     end
-
-    def initialize(digest_class: nil)
-      @digest_class = digest_class || self.class.hash_digest_class
-    end
-
-    def hexdigest(arg)
-      @digest_class.hexdigest(arg).truncate(32)
-    end
   end
 end