From b3ccd7b27afabacba5f537ef5c428314df25eae3 Mon Sep 17 00:00:00 2001
From: Steve Purcell <steve@sanityinc.com>
Date: Mon, 28 May 2012 14:39:09 +0100
Subject: Don't enable validations when passing false hash values to
 ActiveModel.validates

Passing a falsey option value for a validator currently causes that validator to
be enabled, just like "true":

    ActiveModel.validates :foo, :presence => false

This is rather counterintuitive, and makes it inconvenient to wrap `validates` in
methods which may conditionally enable different validators.

As an example, one is currently forced to write:

      def has_slug(source_field, options={:unique => true})
        slugger = Proc.new { |r| r[:slug] = self.class.sluggify(r[source_field]) if r[:slug].blank? }
        before_validation slugger
        validations = { :presence => true, :slug => true }
        if options[:unique]
          validations[:uniqueness] = true
        end
        validates :slug, validations
      end

because the following reasonable-looking alternative fails to work as expected:

      def has_slug(source_field, options={:unique => true})
        slugger = Proc.new { |r| r[:slug] = self.class.sluggify(r[source_field]) if r[:slug].blank? }
        before_validation slugger
        validates :slug, :presence => true, :slug => true, :uniqueness => options[:unique]
      end

(This commit includes a test, and all activemodel and activerecord tests pass as before.)
---
 activemodel/CHANGELOG.md | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'activemodel/CHANGELOG.md')

diff --git a/activemodel/CHANGELOG.md b/activemodel/CHANGELOG.md
index 789cff0673..eb34edb91b 100644
--- a/activemodel/CHANGELOG.md
+++ b/activemodel/CHANGELOG.md
@@ -1,5 +1,7 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*   Passing false hash values to `validates` will no longer enable the corresponding validators *Steve Purcell*
+
 *   `ConfirmationValidator` error messages will attach to `:#{attribute}_confirmation` instead of `attribute` *Brian Cardarella*
 
 *   Added ActiveModel::Model, a mixin to make Ruby objects work with AP out of box *Guillermo Iguaran*
-- 
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