From 8f6e5986acddf1c126bebf27774d7c7866bb4fa7 Mon Sep 17 00:00:00 2001
From: Kassio Borges <kassioborgesm@gmail.com>
Date: Tue, 13 May 2014 11:25:21 -0300
Subject: [PATCH] Fix how to compute class name on habtm namespaced.

Thank's for @laurocaetano for the help with tests. :smiley:

Fixes #14709
---
 activerecord/CHANGELOG.md                            |  6 ++++++
 .../associations/builder/has_and_belongs_to_many.rb  |  6 +++++-
 .../has_and_belongs_to_many_associations_test.rb     | 12 ++++++++++++
 activerecord/test/models/publisher.rb                |  2 ++
 activerecord/test/models/publisher/article.rb        |  3 +++
 activerecord/test/models/publisher/magazine.rb       |  3 +++
 activerecord/test/schema/schema.rb                   | 11 +++++++++++
 7 files changed, 42 insertions(+), 1 deletion(-)
 create mode 100644 activerecord/test/models/publisher.rb
 create mode 100644 activerecord/test/models/publisher/article.rb
 create mode 100644 activerecord/test/models/publisher/magazine.rb

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index f6cd5efb453..755fb32c3ff 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,9 @@
+*   Fix how to calculate associated class name when using `habtm` namespaced.
+
+    Fixes #14709.
+
+    *Kassio Borges*
+
 *   `change_column_default` allows `[]` as argument to `change_column_default`.
 
     Fixes #11586.
diff --git a/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb b/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb
index e4722773748..ad781e50c9a 100644
--- a/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb
+++ b/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb
@@ -23,7 +23,11 @@ module ActiveRecord::Associations::Builder
           KnownTable.new options[:join_table].to_s
         else
           class_name = options.fetch(:class_name) {
-            name.to_s.camelize.singularize
+            model_name = name.to_s.camelize.singularize
+            if parent_name = lhs_class.parent_name.presence
+              model_name = model_name.prepend("#{parent_name}::")
+            end
+            model_name
           }
           KnownClass.new lhs_class, class_name
         end
diff --git a/activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb b/activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb
index cfdfff6af9d..878f1877dbd 100644
--- a/activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb
+++ b/activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb
@@ -22,6 +22,9 @@ require 'models/sponsor'
 require 'models/country'
 require 'models/treaty'
 require 'models/vertex'
+require 'models/publisher'
+require 'models/publisher/article'
+require 'models/publisher/magazine'
 require 'active_support/core_ext/string/conversions'
 
 class ProjectWithAfterCreateHook < ActiveRecord::Base
@@ -848,4 +851,13 @@ class HasAndBelongsToManyAssociationsTest < ActiveRecord::TestCase
   def test_custom_join_table
     assert_equal 'edges', Vertex.reflect_on_association(:sources).join_table
   end
+
+  def test_namespaced_habtm
+    magazine = Publisher::Magazine.create
+    article = Publisher::Article.create
+    magazine.articles << article
+    magazine.save
+
+    assert_includes magazine.articles, article
+  end
 end
diff --git a/activerecord/test/models/publisher.rb b/activerecord/test/models/publisher.rb
new file mode 100644
index 00000000000..0d4a7f92351
--- /dev/null
+++ b/activerecord/test/models/publisher.rb
@@ -0,0 +1,2 @@
+module Publisher
+end
diff --git a/activerecord/test/models/publisher/article.rb b/activerecord/test/models/publisher/article.rb
new file mode 100644
index 00000000000..03a277bbddf
--- /dev/null
+++ b/activerecord/test/models/publisher/article.rb
@@ -0,0 +1,3 @@
+class Publisher::Article < ActiveRecord::Base
+  has_and_belongs_to_many :magazines
+end
diff --git a/activerecord/test/models/publisher/magazine.rb b/activerecord/test/models/publisher/magazine.rb
new file mode 100644
index 00000000000..82e1a14008e
--- /dev/null
+++ b/activerecord/test/models/publisher/magazine.rb
@@ -0,0 +1,3 @@
+class Publisher::Magazine < ActiveRecord::Base
+  has_and_belongs_to_many :articles
+end
diff --git a/activerecord/test/schema/schema.rb b/activerecord/test/schema/schema.rb
index da3074e90f2..a78074d5304 100644
--- a/activerecord/test/schema/schema.rb
+++ b/activerecord/test/schema/schema.rb
@@ -62,6 +62,14 @@ ActiveRecord::Schema.define do
     t.string :name
   end
 
+  create_table :articles, force: true do |t|
+  end
+
+  create_table :articles_magazines, force: true do |t|
+    t.references :article
+    t.references :magazine
+  end
+
   create_table :audit_logs, force: true do |t|
     t.column :message, :string, null: false
     t.column :developer_id, :integer, null: false
@@ -385,6 +393,9 @@ ActiveRecord::Schema.define do
     t.column :custom_lock_version, :integer
   end
 
+  create_table :magazines, force: true do |t|
+  end
+
   create_table :mateys, id: false, force: true do |t|
     t.column :pirate_id, :integer
     t.column :target_id, :integer