Revert "Merge pull request #4490 from EmmanuelOga/master"

This behaviour doesn't actually make sense, the context of
the child should not be affected by the parent. See #10492.

This reverts commit 5f8274efe128ffeec8fa3179460f5167a078f007, reversing
changes made to 81e837e810460d066a2e5fc5a795366ec8ab2313.

activerecord/lib/active_record/autosave_association.rb

@@ -301,7 +301,7 @@ def validate_collection_association(reflection)
     def association_valid?(reflection, record)
       return true if record.destroyed? || record.marked_for_destruction?
 
-      unless valid = record.valid?(validation_context)
+      unless valid = record.valid?
         if reflection.options[:autosave]
           record.errors.each do |attribute, message|
             attribute = "#{reflection.name}.#{attribute}"

activerecord/lib/active_record/validations/associated.rb

@@ -2,7 +2,7 @@ module ActiveRecord
   module Validations
     class AssociatedValidator < ActiveModel::EachValidator #:nodoc:
       def validate_each(record, attribute, value)
-        if Array.wrap(value).reject {|r| r.marked_for_destruction? || r.valid?(record.validation_context) }.any?
+        if Array.wrap(value).reject {|r| r.marked_for_destruction? || r.valid?}.any?
           record.errors.add(attribute, :invalid, options.merge(:value => value))
         end
       end

activerecord/test/cases/validations/association_validation_test.rb

@@ -118,21 +118,4 @@ def test_validates_presence_of_belongs_to_association__existing_parent
     end
   end
 
-  def test_validates_associated_models_in_the_same_context
-    Topic.validates_presence_of :title, :on => :custom_context
-    Topic.validates_associated :replies
-    Reply.validates_presence_of :title, :on => :custom_context
-
-    t = Topic.new('title' => '')
-    r = t.replies.new('title' => '')
-
-    assert t.valid?
-    assert !t.valid?(:custom_context)
-
-    t.title = "Longer"
-    assert !t.valid?(:custom_context), "Should NOT be valid if the associated object is not valid in the same context."
-
-    r.title = "Longer"
-    assert t.valid?(:custom_context), "Should be valid if the associated object is not valid in the same context."
-  end
 end