Improving docs for callbacks execution order [ci skip]

When define callbacks latest definition on the same callback/method
overwrites previous ones.

2 files changed, 6 insertions, 0 deletions

diff --git a/activemodel/lib/active_model/callbacks.rb b/activemodel/lib/active_model/callbacks.rb
index eac2761433..835e6f7716 100644
--- a/activemodel/lib/active_model/callbacks.rb
+++ b/activemodel/lib/active_model/callbacks.rb
@@ -56,6 +56,9 @@ module ActiveModel
   #
   # Would only create the +after_create+ and +before_create+ callback methods in
   # your class.
+  #
+  # NOTE: Calling the same callback multiple times will overwrite previous callback definitions.
+  #
   module Callbacks
     def self.extended(base) #:nodoc:
       base.class_eval do
diff --git a/activemodel/lib/active_model/validations.rb b/activemodel/lib/active_model/validations.rb
index d460068830..9fcde45167 100644
--- a/activemodel/lib/active_model/validations.rb
+++ b/activemodel/lib/active_model/validations.rb
@@ -147,6 +147,9 @@ module ActiveModel
       #   or <tt>unless: Proc.new { |user| user.signup_step <= 2 }</tt>). The
       #   method, proc or string should return or evaluate to a +true+ or +false+
       #   value.
+      #
+      # NOTE: Calling +validate+ multiple times on the same method will overwrite previous definitions.
+      #
       def validate(*args, &block)
         options = args.extract_options!