fix(document): avoid unnecessary clone() in applyGetters() that was triggering additional getters

lib/document.js

@@ -3856,7 +3856,6 @@ Document.prototype.$toObject = function(options, json) {
   // Parent options should only bubble down for subdocuments, not populated docs
   options._parentOptions = this.$isSubdocument ? options : null;
 
-  options._skipSingleNestedGetters = false;
   // remember the root transform function
   // to save it from being overwritten by sub-transform functions
   // const originalTransform = options.transform;
@@ -3870,13 +3869,13 @@ Document.prototype.$toObject = function(options, json) {
     ret = clone(this._doc, options) || {};
   }
 
-  options._skipSingleNestedGetters = true;
   const getters = options._calledWithOptions.getters
     ?? options.getters
     ?? defaultOptions.getters
     ?? false;
+
   if (getters) {
-    applyGetters(this, ret, options);
+    applyGetters(this, ret);
 
     if (options.minimize) {
       ret = minimize(ret) || {};
@@ -4187,12 +4186,11 @@ function applyVirtuals(self, json, options, toObjectOptions) {
  *
  * @param {Document} self
  * @param {Object} json
- * @param {Object} [options]
  * @return {Object} `json`
  * @api private
  */
 
-function applyGetters(self, json, options) {
+function applyGetters(self, json) {
   const schema = self.$__schema;
   const paths = Object.keys(schema.paths);
   let i = paths.length;
@@ -4228,8 +4226,10 @@ function applyGetters(self, json, options) {
       if (branch != null && typeof branch !== 'object') {
         break;
       } else if (ii === last) {
-        const val = self.$get(path);
-        branch[part] = clone(val, options);
+        branch[part] = schema.paths[path].applyGetters(
+          branch[part],
+          self
+        );
         if (Array.isArray(branch[part]) && schema.paths[path].$embeddedSchemaType) {
           for (let i = 0; i < branch[part].length; ++i) {
             branch[part][i] = schema.paths[path].$embeddedSchemaType.applyGetters(

lib/helpers/clone.js

@@ -40,11 +40,6 @@ function clone(obj, options, isArrayChild) {
 
   if (isMongooseObject(obj)) {
     if (options) {
-      // Single nested subdocs should apply getters later in `applyGetters()`
-      // when calling `toObject()`. See gh-7442, gh-8295
-      if (options._skipSingleNestedGetters && obj.$isSingleNested) {
-        options._calledWithOptions = Object.assign({}, options._calledWithOptions || {}, { getters: false });
-      }
       if (options.retainDocuments && obj.$__ != null) {
         const clonedDoc = obj.$clone();
         if (obj.__index != null) {

test/document.test.js

@@ -13843,6 +13843,36 @@ describe('document', function() {
     assert.strictEqual(requiredCalls[0], doc.config.prop);
     assert.strictEqual(requiredCalls[1], doc.config.prop);
   });
+
+  it('applies toObject() getters to 3 level deep subdocuments (gh-14840) (gh-14835)', async function() {
+    // Define nested schemas
+    const Level3Schema = new mongoose.Schema({
+      property: {
+        type: String,
+        get: (value) => value ? value.toUpperCase() : value
+      }
+    });
+
+    const Level2Schema = new mongoose.Schema({ level3: Level3Schema });
+    const Level1Schema = new mongoose.Schema({ level2: Level2Schema });
+    const MainSchema = new mongoose.Schema({ level1: Level1Schema });
+    const MainModel = db.model('Test', MainSchema);
+
+    const doc = await MainModel.create({
+      level1: {
+        level2: {
+          level3: {
+            property: 'testValue'
+          }
+        }
+      }
+    });
+
+    // Fetch and convert the document to an object with getters applied
+    const result = await MainModel.findById(doc._id);
+    const objectWithGetters = result.toObject({ getters: true, virtuals: false });
+    assert.strictEqual(objectWithGetters.level1.level2.level3.property, 'TESTVALUE');
+  });
 });
 
 describe('Check if instance function that is supplied in schema option is available', function() {