Make sure we touch all the parents when touch_later.

The problem was that when saving an object, we would
call touch_later on the parent which wont be saved immediteally, and
it wont call any callbacks. That was working one level up because
we were calling touch, during the touch_later commit phase. However that still
didnt solve the problem when you have a 3+ levels of parents to be touched,
as calling touch would affect the parent, but it would be too late to run callbacks
on its grand-parent.

The solution for this, is instead, call touch_later upwards when the first
touch_later is called. So we make sure all the timestamps are updated without relying
on callbacks.

This also removed the hard dependency BelongsTo builder had with the TouchLater module.
So we can still have the old behaviour if TouchLater module is not included.

[fixes 5f5e6d92]
[related #19324]

activerecord/lib/active_record/associations/builder/belongs_to.rb

@@ -106,8 +106,7 @@ def self.add_touch_callbacks(model, reflection)
       touch       = reflection.options[:touch]
 
       callback = lambda { |record|
-        touch_method = touching_delayed_records? ? :touch : :touch_later
-        BelongsTo.touch_record(record, foreign_key, n, touch, touch_method)
+        BelongsTo.touch_record(record, foreign_key, n, touch, belongs_to_touch_method)
       }
 
       model.after_save    callback, if: :changed?

activerecord/lib/active_record/persistence.rb

@@ -567,5 +567,9 @@ def _raise_record_not_destroyed
     ensure
       @_association_destroy_exception = nil
     end
+
+    def belongs_to_touch_method
+      :touch
+    end
   end
 end

activerecord/lib/active_record/touch_later.rb

@@ -16,6 +16,13 @@ def touch_later(*names) # :nodoc:
 
       surreptitiously_touch @_defer_touch_attrs
       self.class.connection.add_transaction_record self
+
+      # touch the parents as we are not calling the after_save callbacks
+      self.class.reflect_on_all_associations(:belongs_to).each do |r|
+        if touch = r.options[:touch]
+          ActiveRecord::Associations::Builder::BelongsTo.touch_record(self, r.foreign_key, r.name, touch, :touch_later)
+        end
+      end
     end
 
     def touch(*names, time: nil) # :nodoc:
@@ -26,6 +33,7 @@ def touch(*names, time: nil) # :nodoc:
     end
 
     private
+
       def surreptitiously_touch(attrs)
         attrs.each { |attr| write_attribute attr, @_touch_time }
         clear_attribute_changes attrs
@@ -33,9 +41,8 @@ def surreptitiously_touch(attrs)
 
       def touch_deferred_attributes
         if has_defer_touch_attrs? && persisted?
-          @_touching_delayed_records = true
           touch(*@_defer_touch_attrs, time: @_touch_time)
-          @_touching_delayed_records, @_defer_touch_attrs, @_touch_time = nil, nil, nil
+          @_defer_touch_attrs, @_touch_time = nil, nil
         end
       end
 
@@ -43,8 +50,9 @@ def has_defer_touch_attrs?
         defined?(@_defer_touch_attrs) && @_defer_touch_attrs.present?
       end
 
-      def touching_delayed_records?
-        defined?(@_touching_delayed_records) && @_touching_delayed_records
+      def belongs_to_touch_method
+        :touch_later
       end
+
   end
 end

activerecord/test/cases/touch_later_test.rb

@@ -95,8 +95,6 @@ def test_touch_later_dont_hit_the_db
   end
 
   def test_touching_three_deep
-    skip "Pending from #19324"
-
     previous_tree_updated_at        = trees(:root).updated_at
     previous_grandparent_updated_at = nodes(:grandparent).updated_at
     previous_parent_updated_at      = nodes(:parent_a).updated_at