MONGOID-5504 Clear changes after :touch (#5534)

Author: comandeo-mongo

docs/release-notes/mongoid-9.0.txt

@@ -17,6 +17,30 @@ The complete list of releases is available `on GitHub
 please consult GitHub releases for detailed release notes and JIRA for
 the complete list of issues fixed in each release, including bug fixes.
 
+``touch`` method now clears changed state
+-----------------------------------------
+
+In Mongoid 8.x and older ``touch`` method leaves models in the changed state:
+
+.. code-block:: ruby
+
+  # Mongoid 8.x behaviour
+  band = Band.create!
+  band.touch
+  band.changed? # => true
+  band.changes # => {"updated_at"=>[2023-01-30 13:12:57.477191135 UTC, 2023-01-30 13:13:11.482975646 UTC]}
+
+Starting from 9.0 Mongoid now correctly clears changed state after using ``touch``
+method.
+
+.. code-block:: ruby
+
+  # Mongoid 9.0 behaviour
+  band = Band.create!
+  band.touch
+  band.changed? # => false
+  band.changes # => {}
+
 Sandbox Mode for Rails Console
 ------------------------------
 

lib/mongoid/touchable.rb

@@ -23,10 +23,14 @@ module InstanceMethods
       def touch(field = nil)
         return false if _root.new_record?
 
-        touches = _gather_touch_updates(Time.configured.now, field)
-        _root.send(:persist_atomic_operations, '$set' => touches) if touches.present?
+        begin
+          touches = _gather_touch_updates(Time.configured.now, field)
+          _root.send(:persist_atomic_operations, '$set' => touches) if touches.present?
+          _run_touch_callbacks_from_root
+        ensure
+          _clear_touch_updates(field)
+        end
 
-        _run_touch_callbacks_from_root
         true
       end
 
@@ -50,6 +54,17 @@ def _gather_touch_updates(now, field = nil)
         touches
       end
 
+      # Clears changes for the model caused by touch operation.
+      #
+      # @param [ Symbol ] field The name of an additional field to update.
+      #
+      # @api private
+      def _clear_touch_updates(field = nil)
+        remove_change(:updated_at)
+        remove_change(field) if field
+        _parent._clear_touch_updates if _touchable_parent?
+      end
+
       # Recursively runs :touch callbacks for the document and its parents,
       # beginning with the root document and cascading through each successive
       # child document.

spec/mongoid/touchable_spec.rb

@@ -26,6 +26,11 @@
         updatable.touch
         expect(updatable.updated_at).to be > updated_at
       end
+
+      it 'does not leave model in changed state' do
+        updatable.touch
+        expect(updatable).not_to be_changed
+      end
     end
 
     context 'when the document has a parent association' do
@@ -255,8 +260,8 @@
             expect(touched).to be true
           end
 
-          it "keeps changes for next callback" do
-            expect(agent.changes).to_not be_empty
+          it "clears changes" do
+            expect(agent.changes).to be_empty
           end
         end
 
@@ -290,8 +295,8 @@
             expect(touched).to be true
           end
 
-          it "keeps changes for next callback" do
-            expect(agent.changes).to_not be_empty
+          it "clears changes" do
+            expect(agent.changes).to be_empty
           end
         end
       end
@@ -1320,4 +1325,93 @@
       end
     end
   end
+
+  context 'when updated after touch' do
+    let(:touch_time) { Timecop.freeze(Time.at(Time.now.to_i) + 2) }
+
+    let(:update_time) { Timecop.freeze(Time.at(Time.now.to_i) + 4) }
+
+    let!(:book) { Book.create! }
+
+    after do
+      Timecop.return
+    end
+
+    it 'updates updated_at' do
+      touch_time
+      book.touch
+      update_time
+      book.title = 'This book has no name'
+      book.save!
+      expect(book.updated_at).to eq(update_time)
+    end
+  end
+
+  context 'callbacks' do
+    class TouchableParent
+      include Mongoid::Document
+      include Mongoid::Timestamps
+
+      attr_reader :before_touch_called, :after_touch_called
+
+      set_callback(:touch, :before) do
+        @before_touch_called = true
+      end
+
+      set_callback(:touch, :after) do
+        @after_touch_called = true
+      end
+
+      embeds_one :child, inverse_of: :parent, class_name: 'TouchableChild'
+    end
+
+    class TouchableChild
+      include Mongoid::Document
+      include Mongoid::Timestamps
+
+      attr_reader :before_touch_called, :after_touch_called
+
+      set_callback(:touch, :before) do
+        @before_touch_called = true
+      end
+
+      set_callback(:touch, :after) do
+        @after_touch_called = true
+      end
+
+      embedded_in :parent, inverse_of: :child, class_name: 'TouchableParent', touch: true
+    end
+
+    let(:parent) do
+      TouchableParent.create!.tap do |parent|
+        parent.child = TouchableChild.create!(parent: parent)
+      end
+    end
+
+    let(:child) do
+      parent.child
+    end
+
+    it 'calls touch callbacks on parent' do
+      parent.touch
+      expect(parent.before_touch_called).to eq(true)
+      expect(parent.after_touch_called).to eq(true)
+    end
+
+    context 'when touch is calles on a child' do
+      before do
+        child.touch
+      end
+
+      it 'calls touch callbacks on parent' do
+        expect(parent.before_touch_called).to eq(true)
+        expect(parent.after_touch_called).to eq(true)
+      end
+
+      it 'calls touch callbacks on child' do
+        expect(child.before_touch_called).to eq(true)
+        expect(child.after_touch_called).to eq(true)
+      end
+    end
+  end
 end