Merge pull request rails#53345 from tenderlove/init-attributes

Pull attribute initialization in to a function

Author: tenderlove

activemodel/lib/active_model/dirty.rb

@@ -247,12 +247,18 @@ module Dirty
 
     def initialize_dup(other) # :nodoc:
       super
+      @mutations_from_database = nil
+    end
+
+    def init_attributes(other) # :nodoc:
+      attrs = super
       if other.persisted? && self.class.respond_to?(:_default_attributes)
-        @attributes = self.class._default_attributes.map do |attr|
-          attr.with_value_from_user(@attributes.fetch_value(attr.name))
+        self.class._default_attributes.map do |attr|
+          attr.with_value_from_user(attrs.fetch_value(attr.name))
         end
+      else
+        attrs
       end
-      @mutations_from_database = nil
     end
 
     def as_json(options = {}) # :nodoc:

activerecord/lib/active_record/core.rb

@@ -525,12 +525,7 @@ def init_with_attributes(attributes, new_record = false) # :nodoc:
 
     ##
     def initialize_dup(other) # :nodoc:
-      @attributes = @attributes.deep_dup
-      if self.class.composite_primary_key?
-        @primary_key.each { |key| @attributes.reset(key) }
-      else
-        @attributes.reset(@primary_key)
-      end
+      @attributes = init_attributes(other)
 
       _run_initialize_callbacks
 
@@ -542,6 +537,18 @@ def initialize_dup(other) # :nodoc:
       super
     end
 
+    def init_attributes(_) # :nodoc:
+      attrs = @attributes.deep_dup
+
+      if self.class.composite_primary_key?
+        @primary_key.each { |key| attrs.reset(key) }
+      else
+        attrs.reset(@primary_key)
+      end
+
+      attrs
+    end
+
     # Populate +coder+ with attributes about this record that should be
     # serialized. The structure of +coder+ defined in this method is
     # guaranteed to match the structure of +coder+ passed to the #init_with