From 8e2e5f9e3d1f434e265dc104ea9b00ff75702fc3 Mon Sep 17 00:00:00 2001
From: Jon Moss <me@jonathanmoss.me>
Date: Wed, 25 May 2016 20:51:37 -0400
Subject: [PATCH] Fix `has_one` `enum` `where` queries

Fixes #25128
---
 .../lib/active_record/table_metadata.rb        |  3 ++-
 .../associations/has_one_associations_test.rb  | 18 ++++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/activerecord/lib/active_record/table_metadata.rb b/activerecord/lib/active_record/table_metadata.rb
index 0faad48ce3..a1326aa359 100644
--- a/activerecord/lib/active_record/table_metadata.rb
+++ b/activerecord/lib/active_record/table_metadata.rb
@@ -44,7 +44,8 @@ module ActiveRecord
     def associated_table(table_name)
       return self if table_name == arel_table.name
 
-      association = klass._reflect_on_association(table_name)
+      association = klass._reflect_on_association(table_name) || klass._reflect_on_association(table_name.singularize)
+
       if association && !association.polymorphic?
         association_klass = association.klass
         arel_table = association_klass.arel_table.alias(table_name)
diff --git a/activerecord/test/cases/associations/has_one_associations_test.rb b/activerecord/test/cases/associations/has_one_associations_test.rb
index c9d9e29f09..1574f373c2 100644
--- a/activerecord/test/cases/associations/has_one_associations_test.rb
+++ b/activerecord/test/cases/associations/has_one_associations_test.rb
@@ -659,4 +659,22 @@ class HasOneAssociationsTest < ActiveRecord::TestCase
 
     assert_deprecated { firm.account(true) }
   end
+
+  class SpecialBook < ActiveRecord::Base
+    self.table_name = 'books'
+    belongs_to :author, class_name: 'SpecialAuthor'
+  end
+
+  class SpecialAuthor < ActiveRecord::Base
+    self.table_name = 'authors'
+    has_one :book, class_name: 'SpecialBook', foreign_key: 'author_id'
+  end
+
+  def test_assocation_enum_works_properly
+    author = SpecialAuthor.create!(name: 'Test')
+    book = SpecialBook.create!(status: 'published')
+    author.book = book
+
+    refute_equal 0, SpecialAuthor.joins(:book).where(books: { status: 'published' } ).count
+  end
 end