Merge pull request #9733 from senny/9712_option_to_turn_references_deprecation_off

make it possible to disable implicit join references.

activerecord/CHANGELOG.md

 ## Rails 4.0.0 (unreleased) ##
 
+*   Referencing join tables implicitly was deprecated. There is a
+    possibility that these deprecation warnings are shown even if you
+    don't make use of that feature. You can now disable the feature entirely.
+    Fixes #9712.
+
+    Example:
+
+        # in your configuration
+        config.active_record.disable_implicit_join_references = true
+
+        # or directly
+        ActiveRecord::Base.disable_implicit_join_references = true
+
+    *Yves Senn*
+
 *   The `:distinct` option for `Relation#count` is deprecated. You
     should use `Relation#distinct` instead.
 

activerecord/lib/active_record/core.rb

@@ -69,6 +69,14 @@ module Core
       mattr_accessor :timestamped_migrations, instance_writer: false
       self.timestamped_migrations = true
 
+      ##
+      # :singleton-method:
+      # Disable implicit join references. This feature was deprecated with Rails 4.
+      # If you don't make use of implicit references but still see deprecation warnings
+      # you can disable the feature entirely. This will be the default with Rails 4.1.
+      mattr_accessor :disable_implicit_join_references, instance_writer: false
+      self.disable_implicit_join_references = false
+
       class_attribute :connection_handler, instance_writer: false
       self.connection_handler = ConnectionAdapters::ConnectionHandler.new
     end

activerecord/lib/active_record/relation.rb

@@ -595,7 +595,8 @@ def references_eager_loaded_tables?
 
       if (references_values - joined_tables).any?
         true
-      elsif (string_tables - joined_tables).any?
+      elsif !ActiveRecord::Base.disable_implicit_join_references &&
+            (string_tables - joined_tables).any?
         ActiveSupport::Deprecation.warn(
           "It looks like you are eager loading table(s) (one of: #{string_tables.join(', ')}) " \
           "that are referenced in a string SQL snippet. For example: \n" \
@@ -609,7 +610,10 @@ def references_eager_loaded_tables?
           "From now on, you must explicitly tell Active Record when you are referencing a table " \
           "from a string:\n" \
           "\n" \
-          "    Post.includes(:comments).where(\"comments.title = 'foo'\").references(:comments)\n\n"
+          "    Post.includes(:comments).where(\"comments.title = 'foo'\").references(:comments)\n" \
+          "\n" \
+          "If you don't rely on implicit join references you can disable the feature entirely" \
+          "by setting `config.active_record.disable_implicit_join_references = true`."
         )
         true
       else

activerecord/test/cases/relations_test.rb

@@ -1224,6 +1224,15 @@ def test_eager_loading_with_conditions_on_joins
     end
   end
 
+  def test_turn_off_eager_loading_with_conditions_on_joins
+    original_value = ActiveRecord::Base.disable_implicit_join_references
+    ActiveRecord::Base.disable_implicit_join_references = true
+    scope = Topic.where(author_email_address: 'my.example@gmail.com').includes(:replies)
+    assert_not scope.eager_loading?
+  ensure
+     ActiveRecord::Base.time_zone_aware_attributes = original_value
+  end
+
   def test_ordering_with_extra_spaces
     assert_equal authors(:david), Author.order('id DESC , name DESC').last
   end