Not binding polymorphic relation about active_record_union

[siobhandougall]

I'm running into something similar while attempting to update to Rails 4.2.4 (from 4.1.6), and using MySQL. It's not a polymorphic relation, but it looks like a similar parsing error is happening. Here's a really contrived example:

# person.rb
class Person < ActiveRecord::Base
  has_many :active_emails, -> { where active: true }, class_name: 'Email'
  has_many :twitters
end

Say we want to find all people with active emails starting with "johndoe".

Person.joins(:active_emails).where('address like ?', 'johndoe%')

yields

SELECT `people`.* FROM `people` INNER JOIN `emails` ON `emails`.`person_id` = `people`.`id` AND `emails`.`active` = 1 WHERE (address like 'johndoe%')

So far, so good. Now let's say we want to find all people with either an active email starting with "johndoe" or a Twitter handle starting with "johndoe".

Person.joins(:active_emails).where('address like ?', 'johndoe%').union(Person.joins(:twitters).where('handle like ?', 'johndoe%'))

yields

SELECT `people`.* FROM ( (SELECT `people`.* FROM `people` INNER JOIN `emails` ON `emails`.`person_id` = `people`.`id` AND `emails`.`active` =  WHERE (address like 'johndoe%')) UNION (SELECT `people`.* FROM `people` INNER JOIN `twitters` ON `twitters`.`person_id` = `people`.`id` WHERE (handle like 'johndoe%')) ) people

Note that where it used to say, "AND emails.active = 1 WHERE...", the "1" has now mysteriously vanished, and this is no longer valid SQL.

This does not happen with sqlite3, presumably because the original syntax is different:

-- sqlite3 sanitizes out the parameter in the scope block
SELECT "people".* FROM "people" INNER JOIN "emails" ON "emails"."person_id" = "people"."id" AND "emails"."active" = ? WHERE (address like 'johndoe%')  [["active", "t"]]

[brianhempel]

I can reproduce on SQLite…

class User < ActiveRecord::Base
  has_many :posts
  has_many :drafts, -> { where draft: true  }, class_name: "Post"
end

class Post < ActiveRecord::Base
  belongs_to :user
end

User.joins(:drafts).union(User.where(id: 11)).to_sql

SELECT "users".* FROM (
  SELECT "users".*
  FROM "users"
  INNER JOIN "posts" ON "posts"."user_id" = "users"."id" AND "posts"."draft" = 11
  UNION
  SELECT "users".* FROM "users"
  WHERE "users"."id" =
) "users"

[brianhempel]

Thanks for the bug report with the examples. You've been credited in the README.

v1.1.1 is live on RubyGems with the fix in #7.

Let me know if you have any more problems.