MONGOID-5836 Don't repeat callbacks for embedded grandchildren. (mongodb#5933)

* MONGOID-5836 don't explicitly process grandchildren

Grandchildren are already accounted for when this is invoked,
because if called when callbacks are cascading, the input is
the full list of all children and grandchildren. Processing
grandchildren recursively here causes them to be processed twice.

* specify python version to address failing mongo-orchestration

* make sure we don't break update callbacks

Author: jamis

.github/workflows/test.yml

@@ -184,6 +184,13 @@ jobs:
       uses: actions/checkout@v2
       with:
         submodules: recursive
+
+    # the default python 3.8 doesn't cut it, and causes mongo-orchestration
+    # to fail in mongodb-labs/drivers-evergreen-tools.
+    - uses: actions/setup-python@v5
+      with:
+        python-version: '3.13'
+
     - id: start-mongodb
       name: start mongodb
       uses: mongodb-labs/drivers-evergreen-tools@master

lib/mongoid/interceptable.rb

@@ -141,9 +141,13 @@ def run_callbacks(kind, with_children: true, &block)
     # @api private
     def _mongoid_run_child_callbacks(kind, children: nil, &block)
       if Mongoid::Config.around_callbacks_for_embeds
-        _mongoid_run_child_callbacks_with_around(kind, children: children, &block)
+        _mongoid_run_child_callbacks_with_around(kind,
+                                                 children: children,
+                                                 &block)
       else
-        _mongoid_run_child_callbacks_without_around(kind, children: children, &block)
+        _mongoid_run_child_callbacks_without_around(kind,
+                                                    children: children,
+                                                    &block)
       end
     end
 
@@ -219,9 +223,6 @@ def _mongoid_run_child_before_callbacks(kind, children: [], callback_list: [])
         return false if env.halted
         env.value = !env.halted
         callback_list << [next_sequence, env]
-        if (grandchildren = child.send(:cascadable_children, kind))
-          _mongoid_run_child_before_callbacks(kind, children: grandchildren, callback_list: callback_list)
-        end
       end
       callback_list
     end

spec/mongoid/interceptable_spec.rb

@@ -388,6 +388,84 @@ class TestClass
         end
       end
     end
+
+    context 'with embedded grandchildren' do
+      IS = InterceptableSpec
+
+      context 'when creating' do
+        let(:registry) { IS::CallbackRegistry.new(only: %i[ before_save ]) }
+
+        let(:expected_calls) do
+          [
+            # the parent
+            [ IS::CbParent, :before_save ],
+
+            # the immediate child of the parent
+            [ IS::CbCascadedNode, :before_save ],
+
+            # the grandchild of the parent
+            [ IS::CbCascadedNode, :before_save ],
+          ]
+        end
+
+        let!(:parent) do
+          parent = IS::CbParent.new(registry)
+          child = IS::CbCascadedNode.new(registry)
+          grandchild = IS::CbCascadedNode.new(registry)
+
+          child.cb_cascaded_nodes = [ grandchild ]
+          parent.cb_cascaded_nodes = [ child ]
+
+          parent.tap(&:save)
+        end
+
+        it 'should cascade callbacks to grandchildren' do
+          expect(registry.calls).to be == expected_calls
+        end
+      end
+
+      context 'when updating' do
+        let(:registry) { IS::CallbackRegistry.new(only: %i[ before_update ]) }
+
+        let(:expected_calls) do
+          [
+            # the parent
+            [ IS::CbParent, :before_update ],
+
+            # the immediate child of the parent
+            [ IS::CbCascadedNode, :before_update ],
+
+            # the grandchild of the parent
+            [ IS::CbCascadedNode, :before_update ],
+          ]
+        end
+
+        let!(:parent) do
+          parent = IS::CbParent.new(nil)
+          child = IS::CbCascadedNode.new(nil)
+          grandchild = IS::CbCascadedNode.new(nil)
+
+          child.cb_cascaded_nodes = [ grandchild ]
+          parent.cb_cascaded_nodes = [ child ]
+
+          parent.save
+
+          parent.callback_registry = registry
+          child.callback_registry = registry
+          grandchild.callback_registry = registry
+
+          parent.name = 'updated'
+          child.name = 'updated'
+          grandchild.name = 'updated'
+
+          parent.tap(&:save)
+        end
+
+        it 'should cascade callbacks to grandchildren' do
+          expect(registry.calls).to be == expected_calls
+        end
+      end
+    end
   end
 
   describe ".before_destroy" do

spec/mongoid/interceptable_spec_models.rb

@@ -1,10 +1,12 @@
 module InterceptableSpec
   class CallbackRegistry
-    def initialize
+    def initialize(only: [])
       @calls = []
+      @only = only
     end
 
     def record_call(cls, cb)
+      return unless @only.empty? || @only.any? { |pat| pat == cb }
       @calls << [cls, cb]
     end
 
@@ -15,6 +17,8 @@ module CallbackTracking
     extend ActiveSupport::Concern
 
     included do
+      field :name, type: String
+
       %i(
         validation save create update
       ).each do |what|
@@ -34,196 +38,128 @@ module CallbackTracking
         end
       end
     end
-  end
 
-  class CbHasOneParent
-    include Mongoid::Document
-
-    has_one :child, autosave: true, class_name: "CbHasOneChild", inverse_of: :parent
+    attr_accessor :callback_registry
 
-    def initialize(callback_registry)
+    def initialize(callback_registry, *args, **kwargs)
       @callback_registry = callback_registry
-      super()
+      super(*args, **kwargs)
     end
+  end
 
-    attr_accessor :callback_registry
-
+  module RootInsertable
     def insert_as_root
       @callback_registry&.record_call(self.class, :insert_into_database)
       super
     end
+  end
 
+  class CbHasOneParent
+    include Mongoid::Document
     include CallbackTracking
+    include RootInsertable
+
+    has_one :child, autosave: true, class_name: "CbHasOneChild", inverse_of: :parent
   end
 
   class CbHasOneChild
     include Mongoid::Document
+    include CallbackTracking
 
     belongs_to :parent, class_name: "CbHasOneParent", inverse_of: :child
-
-    def initialize(callback_registry)
-      @callback_registry = callback_registry
-      super()
-    end
-
-    attr_accessor :callback_registry
-
-    include CallbackTracking
   end
 
   class CbHasManyParent
     include Mongoid::Document
+    include CallbackTracking
+    include RootInsertable
 
     has_many :children, autosave: true, class_name: "CbHasManyChild", inverse_of: :parent
-
-    def initialize(callback_registry)
-      @callback_registry = callback_registry
-      super()
-    end
-
-    attr_accessor :callback_registry
-
-    def insert_as_root
-      @callback_registry&.record_call(self.class, :insert_into_database)
-      super
-    end
-
-    include CallbackTracking
   end
 
   class CbHasManyChild
     include Mongoid::Document
+    include CallbackTracking
 
     belongs_to :parent, class_name: "CbHasManyParent", inverse_of: :children
-
-    def initialize(callback_registry)
-      @callback_registry = callback_registry
-      super()
-    end
-
-    attr_accessor :callback_registry
-
-    include CallbackTracking
   end
 
   class CbEmbedsOneParent
     include Mongoid::Document
+    include CallbackTracking
+    include RootInsertable
 
     field :name
 
     embeds_one :child, cascade_callbacks: true, class_name: "CbEmbedsOneChild", inverse_of: :parent
-
-    def initialize(callback_registry)
-      @callback_registry = callback_registry
-      super()
-    end
-
-    attr_accessor :callback_registry
-
-    def insert_as_root
-      @callback_registry&.record_call(self.class, :insert_into_database)
-      super
-    end
-
-    include CallbackTracking
   end
 
   class CbEmbedsOneChild
     include Mongoid::Document
+    include CallbackTracking
 
     field :age
 
     embedded_in :parent, class_name: "CbEmbedsOneParent", inverse_of: :child
-
-    def initialize(callback_registry)
-      @callback_registry = callback_registry
-      super()
-    end
-
-    attr_accessor :callback_registry
-
-    include CallbackTracking
   end
 
   class CbEmbedsManyParent
     include Mongoid::Document
+    include CallbackTracking
+    include RootInsertable
 
     embeds_many :children, cascade_callbacks: true, class_name: "CbEmbedsManyChild", inverse_of: :parent
-
-    def initialize(callback_registry)
-      @callback_registry = callback_registry
-      super()
-    end
-
-    attr_accessor :callback_registry
-
-    def insert_as_root
-      @callback_registry&.record_call(self.class, :insert_into_database)
-      super
-    end
-
-    include CallbackTracking
   end
 
   class CbEmbedsManyChild
     include Mongoid::Document
+    include CallbackTracking
 
     embedded_in :parent, class_name: "CbEmbedsManyParent", inverse_of: :children
-
-    def initialize(callback_registry)
-      @callback_registry = callback_registry
-      super()
-    end
-
-    attr_accessor :callback_registry
-
-    include CallbackTracking
   end
 
   class CbParent
     include Mongoid::Document
-
-    def initialize(callback_registry)
-      @callback_registry = callback_registry
-      super()
-    end
-
-    attr_accessor :callback_registry
+    include CallbackTracking
 
     embeds_many :cb_children
     embeds_many :cb_cascaded_children, cascade_callbacks: true
-
-    include CallbackTracking
+    embeds_many :cb_cascaded_nodes, cascade_callbacks: true, as: :parent
   end
 
   class CbChild
     include Mongoid::Document
+    include CallbackTracking
 
     embedded_in :cb_parent
-
-    def initialize(callback_registry, options)
-      @callback_registry = callback_registry
-      super(options)
-    end
-
-    attr_accessor :callback_registry
-
-    include CallbackTracking
   end
 
   class CbCascadedChild
     include Mongoid::Document
+    include CallbackTracking
 
     embedded_in :cb_parent
 
-    def initialize(callback_registry, options)
-      @callback_registry = callback_registry
-      super(options)
-    end
+    before_save :test_mongoid_state
 
-    attr_accessor :callback_registry
+    private
+
+    # Helps test that cascading child callbacks have access to the Mongoid
+    # state objects; if the implementation uses fiber-local (instead of truly
+    # thread-local) variables, the related tests will fail because the
+    # cascading child callbacks use fibers to linearize the recursion.
+    def test_mongoid_state
+      Mongoid::Threaded.stack('interceptable').push(self)
+    end
+  end
 
+  class CbCascadedNode
+    include Mongoid::Document
     include CallbackTracking
+
+    embedded_in :parent, polymorphic: true
+
+    embeds_many :cb_cascaded_nodes, cascade_callbacks: true, as: :parent
   end
 end