Merge branch 'master' into set_binds

* master: (2794 commits)
  doc, API example on how to use `Model#exists?` with multiple IDs. [ci skip]
  Restore DATABASE_URL even if it's nil in connection_handler test
  [ci skip] - error_messages_for has been deprecated since 2.3.8 - lets reduce any confusion for users
  Ensure Active Record connection consistency
  Revert "ask the fixture set for the sql statements"
  Check `respond_to` before delegation due to: https://github.com/ruby/ruby/commit/d781caaf313b8649948c107bba277e5ad7307314
  Adding Hash#compact and Hash#compact! methods
  MySQL version 4.1 was EOL on December 31, 2009 We should at least recommend modern versions of MySQL to users.
  clear cache on body close so that cache remains during rendering
  add a more restricted codepath for templates fixes #13390
  refactor generator tests to use block form of Tempfile
  Fix typo [ci skip]
  Move finish_template as the last public method in the generator
  Minor typos fix [ci skip]
  make `change_column_null` reversible. Closes #13576.
  create/drop test and development databases only if RAILS_ENV is nil
  Revert "Speedup String#to"
  typo fix in test name. [ci skip].
  `core_ext/string/access.rb` test what we are documenting.
  Fix typo in image_tag documentation
  ...

Conflicts:
	activerecord/lib/active_record/associations/join_dependency/join_association.rb
	activerecord/lib/active_record/relation/query_methods.rb

1 files changed, 52 insertions, 1 deletions

diff --git a/activerecord/test/cases/associations/inverse_associations_test.rb b/activerecord/test/cases/associations/inverse_associations_test.rb
index b1f0be3204..893030345f 100644
--- a/activerecord/test/cases/associations/inverse_associations_test.rb
+++ b/activerecord/test/cases/associations/inverse_associations_test.rb
@@ -9,10 +9,24 @@ require 'models/rating'
 require 'models/comment'
 require 'models/car'
 require 'models/bulb'
+require 'models/mixed_case_monkey'
 
 class AutomaticInverseFindingTests < ActiveRecord::TestCase
   fixtures :ratings, :comments, :cars
 
+  def test_has_one_and_belongs_to_should_find_inverse_automatically_on_multiple_word_name
+    monkey_reflection = MixedCaseMonkey.reflect_on_association(:man)
+    man_reflection = Man.reflect_on_association(:mixed_case_monkey)
+
+    assert_respond_to monkey_reflection, :has_inverse?
+    assert monkey_reflection.has_inverse?, "The monkey reflection should have an inverse"
+    assert_equal man_reflection, monkey_reflection.inverse_of, "The monkey reflection's inverse should be the man reflection"
+
+    assert_respond_to man_reflection, :has_inverse?
+    assert man_reflection.has_inverse?, "The man reflection should have an inverse"
+    assert_equal monkey_reflection, man_reflection.inverse_of, "The man reflection's inverse should be the monkey reflection"
+  end
+
   def test_has_one_and_belongs_to_should_find_inverse_automatically
     car_reflection = Car.reflect_on_association(:bulb)
     bulb_reflection = Bulb.reflect_on_association(:car)
@@ -401,10 +415,22 @@ class InverseHasManyTests < ActiveRecord::TestCase
     assert_equal man.name, man.interests.find(interest.id).man.name, "The name of the man should match after the child name is changed"
   end
 
+  def test_find_on_child_instance_with_id_should_not_load_all_child_records
+    man = Man.create!
+    interest = Interest.create!(man: man)
+
+    man.interests.find(interest.id)
+    assert_not man.interests.loaded?
+  end
+
   def test_raise_record_not_found_error_when_invalid_ids_are_passed
+    # delete all interest records to ensure that hard coded invalid_id(s)
+    # are indeed invalid.
+    Interest.delete_all
+
     man = Man.create!
 
-    invalid_id = 2394823094892348920348523452345
+    invalid_id = 245324523
     assert_raise(ActiveRecord::RecordNotFound) { man.interests.find(invalid_id) }
 
     invalid_ids = [8432342, 2390102913, 2453245234523452]
@@ -420,6 +446,19 @@ class InverseHasManyTests < ActiveRecord::TestCase
   def test_trying_to_use_inverses_that_dont_exist_should_raise_an_error
     assert_raise(ActiveRecord::InverseOfAssociationNotFoundError) { Man.first.secret_interests }
   end
+
+  def test_child_instance_should_point_to_parent_without_saving
+    man = Man.new
+    i = Interest.create(:topic => 'Industrial Revolution Re-enactment')
+
+    man.interests << i
+    assert_not_nil i.man
+
+    i.man.name = "Charles"
+    assert_equal i.man.name, man.name
+
+    assert !man.persisted?
+  end
 end
 
 class InverseBelongsToTests < ActiveRecord::TestCase
@@ -564,6 +603,18 @@ class InversePolymorphicBelongsToTests < ActiveRecord::TestCase
     assert_equal face.description, new_man.polymorphic_face.description, "Description of face should be the same after changes to replaced-parent-owned instance"
   end
 
+  def test_inversed_instance_should_not_be_reloaded_after_stale_state_changed
+    new_man = Man.new
+    face = Face.new
+    new_man.face = face
+
+    old_inversed_man = face.man
+    new_man.save!
+    new_inversed_man = face.man
+
+    assert_equal old_inversed_man.object_id, new_inversed_man.object_id
+  end
+
   def test_should_not_try_to_set_inverse_instances_when_the_inverse_is_a_has_many
     i = interests(:llama_wrangling)
     m = i.polymorphic_man