Use bind values for joined tables in where statements

In practical terms, this allows serialized columns and tz aware columns
to be used in wheres that go through joins, where they previously would
not behave correctly. Internally, this removes 1/3 of the cases where we
rely on Arel to perform type casting for us.

There were two non-obvious changes required for this. `update_all` on
relation was merging its bind values with arel's in the wrong order.
Additionally, through associations were assuming there would be no bind
parameters in the preloader (presumably because the where would always
be part of a join)

[Melanie Gilman & Sean Griffin]

2 files changed, 5 insertions, 0 deletions

diff --git a/activerecord/test/models/author.rb b/activerecord/test/models/author.rb
index 3f34d09a04..3da3a1fd59 100644
--- a/activerecord/test/models/author.rb
+++ b/activerecord/test/models/author.rb
@@ -1,5 +1,6 @@
 class Author < ActiveRecord::Base
   has_many :posts
+  has_many :serialized_posts
   has_one :post
   has_many :very_special_comments, :through => :posts
   has_many :posts_with_comments, -> { includes(:comments) }, :class_name => "Post"
diff --git a/activerecord/test/models/post.rb b/activerecord/test/models/post.rb
index 67027cbc22..36cf221d45 100644
--- a/activerecord/test/models/post.rb
+++ b/activerecord/test/models/post.rb
@@ -233,3 +233,7 @@ class PostWithCommentWithDefaultScopeReferencesAssociation < ActiveRecord::Base
   has_many :comment_with_default_scope_references_associations, foreign_key: :post_id
   has_one :first_comment, class_name: "CommentWithDefaultScopeReferencesAssociation", foreign_key: :post_id
 end
+
+class SerializedPost < ActiveRecord::Base
+  serialize :title
+end