Allow errors to remove duplicates, and ensure cyclic associations w/ autosave duplicate errors can be removed

See SHA 7550f0a016ee6647aaa76c0c0ae30bebc3867288

2 files changed, 16 insertions, 1 deletions

diff --git a/activemodel/lib/active_model/error.rb b/activemodel/lib/active_model/error.rb
index b1912f2604..9731fa74df 100644
--- a/activemodel/lib/active_model/error.rb
+++ b/activemodel/lib/active_model/error.rb
@@ -62,5 +62,20 @@ module ActiveModel
 
       full_message == Error.new(@base, attribute, type, **options).full_message
     end
+
+    def ==(other)
+      attributes_for_hash == other.attributes_for_hash
+    end
+    alias eql? ==
+
+    def hash
+      attributes_for_hash.hash
+    end
+
+    protected
+
+      def attributes_for_hash
+        [@base, @attribute, @raw_type, @options]
+      end
   end
 end
diff --git a/activemodel/lib/active_model/errors.rb b/activemodel/lib/active_model/errors.rb
index bb64bc6264..2d559e06d4 100644
--- a/activemodel/lib/active_model/errors.rb
+++ b/activemodel/lib/active_model/errors.rb
@@ -64,7 +64,7 @@ module ActiveModel
     include Enumerable
 
     extend Forwardable
-    def_delegators :@errors, :size, :clear, :blank?, :empty?
+    def_delegators :@errors, :size, :clear, :blank?, :empty?, :uniq!
     # TODO: forward all enumerable methods after `each` deprecation is removed.
     def_delegators :@errors, :count