1 files changed, 9 insertions, 1 deletions
diff --git a/activemodel/lib/active_model/errors.rb b/activemodel/lib/active_model/errors.rb
index ac19b4625e..a9af426fb1 100644
--- a/activemodel/lib/active_model/errors.rb
+++ b/activemodel/lib/active_model/errors.rb
@@ -318,7 +318,7 @@ module ActiveModel
       group_by_attribute.each do |attribute, errors|
         hash[attribute] = errors.map(&:detail)
       end
-      hash
+      DeprecationHandlingDetailsHash.new(hash)
     end
 
     def group_by_attribute
@@ -672,6 +672,14 @@ module ActiveModel
     end
   end
 
+  class DeprecationHandlingDetailsHash < SimpleDelegator
+    def initialize(details)
+      details.default = []
+      details.freeze
+      super(details)
+    end
+  end
+
   # Raised when a validation cannot be corrected by end users and are considered
   # exceptional.
   #