diff --git a/lib/document.js b/lib/document.js
index 45da5eb3f1..3f6a26b67e 100644
--- a/lib/document.js
+++ b/lib/document.js
@@ -198,7 +198,7 @@ function Document(obj, fields, options) {
     const _this = this;
     const keys = Object.keys(this._doc);
 
-    keys.forEach(function(key) {
+    keys.forEach(function (key) {
       // Avoid methods, virtuals, existing fields, and `$` keys. The latter is to avoid overwriting
       // Mongoose internals.
       if (!(key in schema.tree) && !(key in schema.methods) && !(key in schema.virtuals) && !key.startsWith('$')) {
@@ -264,10 +264,10 @@ Document.prototype.$isMongooseDocumentPrototype = true;
  */
 
 Object.defineProperty(Document.prototype, 'isNew', {
-  get: function() {
+  get: function () {
     return this.$isNew;
   },
-  set: function(value) {
+  set: function (value) {
     this.$isNew = value;
   }
 });
@@ -282,10 +282,10 @@ Object.defineProperty(Document.prototype, 'isNew', {
  */
 
 Object.defineProperty(Document.prototype, 'errors', {
-  get: function() {
+  get: function () {
     return this.$errors;
   },
-  set: function(value) {
+  set: function (value) {
     this.$errors = value;
   }
 });
@@ -303,8 +303,8 @@ Document.prototype.$isNew = true;
 utils.each(
   ['on', 'once', 'emit', 'listeners', 'removeListener', 'setMaxListeners',
     'removeAllListeners', 'addListener'],
-  function(emitterFn) {
-    Document.prototype[emitterFn] = function() {
+  function (emitterFn) {
+    Document.prototype[emitterFn] = function () {
       // Delay creating emitter until necessary because emitters take up a lot of memory,
       // especially for subdocuments.
       if (!this.$__.emitter) {
@@ -373,13 +373,13 @@ Document.prototype.schema;
 Object.defineProperty(Document.prototype, '$locals', {
   configurable: false,
   enumerable: false,
-  get: function() {
+  get: function () {
     if (this.$__.locals == null) {
       this.$__.locals = {};
     }
     return this.$__.locals;
   },
-  set: function(v) {
+  set: function (v) {
     this.$__.locals = v;
   }
 });
@@ -469,10 +469,10 @@ Document.prototype.$errors;
  */
 
 Object.defineProperty(Document.prototype, '$op', {
-  get: function() {
+  get: function () {
     return this.$__.op || null;
   },
-  set: function(value) {
+  set: function (value) {
     this.$__.op = value;
   }
 });
@@ -556,7 +556,7 @@ function $applyDefaultsToNested(val, path, doc) {
  * @instance
  */
 
-Document.prototype.$__buildDoc = function(obj, fields, skipId, exclude, hasIncludedChildren) {
+Document.prototype.$__buildDoc = function (obj, fields, skipId, exclude, hasIncludedChildren) {
   const doc = {};
 
   const paths = Object.keys(this.$__schema.paths).
@@ -620,7 +620,7 @@ Document.prototype.$__buildDoc = function(obj, fields, skipId, exclude, hasInclu
  * Converts to POJO when you use the document for querying
  */
 
-Document.prototype.toBSON = function() {
+Document.prototype.toBSON = function () {
   return this.toObject(internalToObjectOptions);
 };
 
@@ -642,7 +642,7 @@ Document.prototype.toBSON = function() {
  * @instance
  */
 
-Document.prototype.init = function(doc, opts, fn) {
+Document.prototype.init = function (doc, opts, fn) {
   if (typeof opts === 'function') {
     fn = opts;
     opts = null;
@@ -663,7 +663,7 @@ Document.prototype.init = function(doc, opts, fn) {
  * @api public
  */
 
-Document.prototype.$init = function() {
+Document.prototype.$init = function () {
   return this.constructor.prototype.init.apply(this, arguments);
 };
 
@@ -676,7 +676,10 @@ Document.prototype.$init = function() {
  * @api private
  */
 
-Document.prototype.$__init = function(doc, opts) {
+Document.prototype.$__init = function (doc, opts) {
+  if (doc == null) {
+    throw new ObjectParameterError(doc, 'doc', 'init');
+  }
   this.$isNew = false;
   opts = opts || {};
 
@@ -1121,10 +1124,10 @@ Document.prototype.$set = function $set(path, val, type, options) {
       // On initial set, delete any nested keys if we're going to overwrite
       // them to ensure we keep the user's key order.
       if (type === true &&
-          !prefix &&
-          valForKey != null &&
-          pathtype === 'nested' &&
-          this._doc[key] != null) {
+        !prefix &&
+        valForKey != null &&
+        pathtype === 'nested' &&
+        this._doc[key] != null) {
         delete this._doc[key];
       }
 
@@ -1135,7 +1138,7 @@ Document.prototype.$set = function $set(path, val, type, options) {
       } else if (strict) {
         // Don't overwrite defaults with undefined keys (gh-3981) (gh-9039)
         if (constructing && valForKey === void 0 &&
-            this.$get(pathName) !== void 0) {
+          this.$get(pathName) !== void 0) {
           continue;
         }
 
@@ -1167,8 +1170,8 @@ Document.prototype.$set = function $set(path, val, type, options) {
     const orderedKeys = Object.keys(this.$__schema.tree);
     for (let i = 0, len = orderedKeys.length; i < len; ++i) {
       (key = orderedKeys[i]) &&
-      (this._doc.hasOwnProperty(key)) &&
-      (orderedDoc[key] = undefined);
+        (this._doc.hasOwnProperty(key)) &&
+        (orderedDoc[key] = undefined);
     }
     this._doc = Object.assign(orderedDoc, this._doc);
 
@@ -1242,8 +1245,8 @@ Document.prototype.$set = function $set(path, val, type, options) {
         this.$set(path + '.' + key, val[key], constructing, { ...options, _skipMarkModified: true });
       }
       if (priorVal != null &&
-          (!wasModified || hasInitialVal) &&
-          utils.deepEqual(hasInitialVal ? this.$__.savedState[path] : priorVal, val)) {
+        (!wasModified || hasInitialVal) &&
+        utils.deepEqual(hasInitialVal ? this.$__.savedState[path] : priorVal, val)) {
         this.unmarkModified(path);
       } else {
         this.markModified(path);
@@ -1424,13 +1427,13 @@ Document.prototype.$set = function $set(path, val, type, options) {
     let popOpts;
     const typeKey = this.$__schema.options.typeKey;
     if (schema.options &&
-        Array.isArray(schema.options[typeKey]) &&
-        schema.options[typeKey].length &&
-        schema.options[typeKey][0] &&
-        schema.options[typeKey][0].ref &&
-        _isManuallyPopulatedArray(val, schema.options[typeKey][0].ref)) {
+      Array.isArray(schema.options[typeKey]) &&
+      schema.options[typeKey].length &&
+      schema.options[typeKey][0] &&
+      schema.options[typeKey][0].ref &&
+      _isManuallyPopulatedArray(val, schema.options[typeKey][0].ref)) {
       popOpts = { [populateModelSymbol]: val[0].constructor };
-      this.$populated(path, val.map(function(v) { return v._doc._id; }), popOpts);
+      this.$populated(path, val.map(function (v) { return v._doc._id; }), popOpts);
 
       for (const doc of val) {
         doc.$__.wasPopulated = { value: doc._doc._id };
@@ -1455,12 +1458,12 @@ Document.prototype.$set = function $set(path, val, type, options) {
     }
 
     if (Array.isArray(val) &&
-        !Array.isArray(schema) &&
-        schema.$isMongooseDocumentArray &&
-        val.length !== 0 &&
-        val[0] != null &&
-        val[0].$__ != null &&
-        val[0].$__.populated != null) {
+      !Array.isArray(schema) &&
+      schema.$isMongooseDocumentArray &&
+      val.length !== 0 &&
+      val[0] != null &&
+      val[0].$__ != null &&
+      val[0].$__.populated != null) {
       const populatedPaths = Object.keys(val[0].$__.populated);
       for (const populatedPath of populatedPaths) {
         this.$populated(path + '.' + populatedPath,
@@ -1523,9 +1526,9 @@ Document.prototype.$set = function $set(path, val, type, options) {
       this.$__.session[sessionNewDocuments].get(this).modifiedPaths &&
       !this.$__.session[sessionNewDocuments].get(this).modifiedPaths.has(savedStatePath);
     if (savedState != null &&
-        savedState.hasOwnProperty(savedStatePath) &&
-        (!isInTransaction || isModifiedWithinTransaction) &&
-        utils.deepEqual(val, savedState[savedStatePath])) {
+      savedState.hasOwnProperty(savedStatePath) &&
+      (!isInTransaction || isModifiedWithinTransaction) &&
+      utils.deepEqual(val, savedState[savedStatePath])) {
       this.unmarkModified(path);
     }
   }
@@ -1624,7 +1627,7 @@ Document.prototype.set = Document.prototype.$set;
  * @instance
  */
 
-Document.prototype.$__shouldModify = function(pathToMark, path, options, constructing, parts, schema, val, priorVal) {
+Document.prototype.$__shouldModify = function (pathToMark, path, options, constructing, parts, schema, val, priorVal) {
   if (options && options._skipMarkModified) {
     return false;
   }
@@ -1650,8 +1653,8 @@ Document.prototype.$__shouldModify = function(pathToMark, path, options, constru
   // gh-3992: if setting a populated field to a doc, don't mark modified
   // if they have the same _id
   if (this.$populated(path) &&
-      val instanceof Document &&
-      deepEqual(val._doc._id, priorVal)) {
+    val instanceof Document &&
+    deepEqual(val._doc._id, priorVal)) {
     return false;
   }
 
@@ -1660,10 +1663,10 @@ Document.prototype.$__shouldModify = function(pathToMark, path, options, constru
   }
 
   if (!constructing &&
-      val !== null &&
-      val !== undefined &&
-      path in this.$__.activePaths.getStatePaths('default') &&
-      deepEqual(val, schema.getDefault(this, constructing))) {
+    val !== null &&
+    val !== undefined &&
+    path in this.$__.activePaths.getStatePaths('default') &&
+    deepEqual(val, schema.getDefault(this, constructing))) {
     // a path with a default was $unset on the server
     // and the user is setting it to the same value again
     return true;
@@ -1688,7 +1691,7 @@ Document.prototype.$__shouldModify = function(pathToMark, path, options, constru
  * @instance
  */
 
-Document.prototype.$__set = function(pathToMark, path, options, constructing, parts, schema, val, priorVal) {
+Document.prototype.$__set = function (pathToMark, path, options, constructing, parts, schema, val, priorVal) {
   Embedded = Embedded || require('./types/arraySubdocument');
 
   const shouldModify = this.$__shouldModify(pathToMark, path, options, constructing, parts,
@@ -1710,7 +1713,7 @@ Document.prototype.$__set = function(pathToMark, path, options, constructing, pa
 
       // Update embedded document parent references (gh-5189)
       if (utils.isMongooseDocumentArray(val)) {
-        val.forEach(function(item) {
+        val.forEach(function (item) {
           item && item.__parentArray && (item.__parentArray = val);
         });
       }
@@ -1790,7 +1793,7 @@ Document.prototype.$__set = function(pathToMark, path, options, constructing, pa
  * @api private
  */
 
-Document.prototype.$__getValue = function(path) {
+Document.prototype.$__getValue = function (path) {
   if (typeof path !== 'string' && !Array.isArray(path)) {
     throw new TypeError(
       `Invalid \`path\`. Must be either string or array. Got "${path}" (type ${typeof path})`
@@ -1882,7 +1885,7 @@ Document.prototype.$inc = function $inc(path, val) {
  * @api private
  */
 
-Document.prototype.$__setValue = function(path, val) {
+Document.prototype.$__setValue = function (path, val) {
   utils.setValue(path, val, this._doc);
   return this;
 };
@@ -1907,7 +1910,7 @@ Document.prototype.$__setValue = function(path, val) {
  * @api public
  */
 
-Document.prototype.get = function(path, type, options) {
+Document.prototype.get = function (path, type, options) {
   let adhoc;
   if (options == null) {
     options = {};
@@ -2003,7 +2006,7 @@ Document.prototype.$get = Document.prototype.get;
  * @instance
  */
 
-Document.prototype.$__path = function(path) {
+Document.prototype.$__path = function (path) {
   const adhocs = this.$__.adhocPaths;
   const adhocType = adhocs && adhocs.hasOwnProperty(path) ? adhocs[path] : null;
 
@@ -2029,7 +2032,7 @@ Document.prototype.$__path = function(path) {
  * @api public
  */
 
-Document.prototype.markModified = function(path, scope) {
+Document.prototype.markModified = function (path, scope) {
   this.$__saveInitialState(path);
 
   this.$__.activePaths.modify(path);
@@ -2068,7 +2071,7 @@ Document.prototype.$__saveInitialState = function $__saveInitialState(path) {
  * @api public
  */
 
-Document.prototype.unmarkModified = function(path) {
+Document.prototype.unmarkModified = function (path) {
   this.$__.activePaths.init(path);
   if (this.$__.pathsToScopes != null) {
     delete this.$__.pathsToScopes[path];
@@ -2091,7 +2094,7 @@ Document.prototype.unmarkModified = function(path) {
  * @api public
  */
 
-Document.prototype.$ignore = function(path) {
+Document.prototype.$ignore = function (path) {
   this.$__.activePaths.ignore(path);
 };
 
@@ -2118,7 +2121,7 @@ Document.prototype.$ignore = function(path) {
  * @api public
  */
 
-Document.prototype.directModifiedPaths = function() {
+Document.prototype.directModifiedPaths = function () {
   return Object.keys(this.$__.activePaths.getStatePaths('modify'));
 };
 
@@ -2147,7 +2150,7 @@ Document.prototype.directModifiedPaths = function() {
  * @return {Boolean}
  */
 
-Document.prototype.$isEmpty = function(path) {
+Document.prototype.$isEmpty = function (path) {
   const isEmptyOptions = {
     minimize: true,
     virtuals: false,
@@ -2200,7 +2203,7 @@ function _isEmpty(v) {
  * @api public
  */
 
-Document.prototype.modifiedPaths = function(options) {
+Document.prototype.modifiedPaths = function (options) {
   options = options || {};
 
   const directModifiedPaths = Object.keys(this.$__.activePaths.getStatePaths('modify'));
@@ -2282,7 +2285,7 @@ Document.prototype[documentModifiedPaths] = Document.prototype.modifiedPaths;
  * @api public
  */
 
-Document.prototype.isModified = function(paths, options, modifiedPaths) {
+Document.prototype.isModified = function (paths, options, modifiedPaths) {
   if (paths) {
     const ignoreAtomics = options && options.ignoreAtomics;
     const directModifiedPathsObj = this.$__.activePaths.states.modify;
@@ -2301,7 +2304,7 @@ Document.prototype.isModified = function(paths, options, modifiedPaths) {
     }
 
     const modified = modifiedPaths || this[documentModifiedPaths]();
-    const isModifiedChild = paths.some(function(path) {
+    const isModifiedChild = paths.some(function (path) {
       return !!~modified.indexOf(path);
     });
 
@@ -2315,8 +2318,8 @@ Document.prototype.isModified = function(paths, options, modifiedPaths) {
         return true;
       });
     }
-    return isModifiedChild || paths.some(function(path) {
-      return directModifiedPaths.some(function(mod) {
+    return isModifiedChild || paths.some(function (path) {
+      return directModifiedPaths.some(function (mod) {
         return mod === path || path.startsWith(mod + '.');
       });
     });
@@ -2354,7 +2357,7 @@ Document.prototype[documentIsModified] = Document.prototype.isModified;
  * @api public
  */
 
-Document.prototype.$isDefault = function(path) {
+Document.prototype.$isDefault = function (path) {
   if (path == null) {
     return this.$__.activePaths.some('default');
   }
@@ -2393,7 +2396,7 @@ Document.prototype.$isDefault = function(path) {
  * @api public
  */
 
-Document.prototype.$isDeleted = function(val) {
+Document.prototype.$isDeleted = function (val) {
   if (arguments.length === 0) {
     return !!this.$__.isDeleted;
   }
@@ -2416,7 +2419,7 @@ Document.prototype.$isDeleted = function(val) {
  * @api public
  */
 
-Document.prototype.isDirectModified = function(path) {
+Document.prototype.isDirectModified = function (path) {
   if (path == null) {
     return this.$__.activePaths.some('modify');
   }
@@ -2455,7 +2458,7 @@ Document.prototype.isDirectModified = function(path) {
  * @api public
  */
 
-Document.prototype.isInit = function(path) {
+Document.prototype.isInit = function (path) {
   if (path == null) {
     return this.$__.activePaths.some('init');
   }
@@ -2710,7 +2713,7 @@ function _getPathsToValidate(doc, pathsToValidate, pathsToSkip, isNestedValidate
 
   _evaluateRequiredFunctions(doc);
   // only validate required fields when necessary
-  let paths = new Set(Object.keys(doc.$__.activePaths.getStatePaths('require')).filter(function(path) {
+  let paths = new Set(Object.keys(doc.$__.activePaths.getStatePaths('require')).filter(function (path) {
     if (!doc.$__isSelected(path) && !doc.$isModified(path)) {
       return false;
     }
@@ -2777,10 +2780,10 @@ function _getPathsToValidate(doc, pathsToValidate, pathsToSkip, isNestedValidate
           throw new Error('Cannot validate subdocument that does not have a parent');
         }
         if (doc.$isModified(fullPathToSubdoc, null, modifiedPaths) &&
-              // Avoid using isDirectModified() here because that does additional checks on whether the parent path
-              // is direct modified, which can cause performance issues re: gh-14897
-              !subdocParent.$__.activePaths.getStatePaths('modify').hasOwnProperty(fullPathToSubdoc) &&
-              !subdocParent.$isDefault(fullPathToSubdoc)) {
+          // Avoid using isDirectModified() here because that does additional checks on whether the parent path
+          // is direct modified, which can cause performance issues re: gh-14897
+          !subdocParent.$__.activePaths.getStatePaths('modify').hasOwnProperty(fullPathToSubdoc) &&
+          !subdocParent.$isDefault(fullPathToSubdoc)) {
           paths.add(fullPathToSubdoc);
 
           if (doc.$__.pathsToScopes == null) {
@@ -2893,21 +2896,21 @@ function _addArrayPathsToValidate(doc, paths) {
     }
 
     if (!_pathType.$isMongooseArray ||
-        // To avoid potential performance issues, skip doc arrays whose children
-        // are not required. `getPositionalPathType()` may be slow, so avoid
-        // it unless we have a case of #6364
-        (!Array.isArray(_pathType) &&
-          _pathType.$isMongooseDocumentArray &&
-          !(_pathType && _pathType.schemaOptions && _pathType.schemaOptions.required))) {
+      // To avoid potential performance issues, skip doc arrays whose children
+      // are not required. `getPositionalPathType()` may be slow, so avoid
+      // it unless we have a case of #6364
+      (!Array.isArray(_pathType) &&
+        _pathType.$isMongooseDocumentArray &&
+        !(_pathType && _pathType.schemaOptions && _pathType.schemaOptions.required))) {
       continue;
     }
 
     // gh-11380: optimization. If the array isn't a document array and there's no validators
     // on the array type, there's no need to run validation on the individual array elements.
     if (_pathType.$isMongooseArray &&
-        !_pathType.$isMongooseDocumentArray && // Skip document arrays...
-        !_pathType.embeddedSchemaType.$isMongooseArray && // and arrays of arrays
-        _pathType.embeddedSchemaType.validators.length === 0) {
+      !_pathType.$isMongooseDocumentArray && // Skip document arrays...
+      !_pathType.embeddedSchemaType.$isMongooseArray && // and arrays of arrays
+      _pathType.embeddedSchemaType.validators.length === 0) {
       continue;
     }
 
@@ -2962,8 +2965,8 @@ Document.prototype.$__validate = async function $__validate(pathsToValidate, opt
   }
 
   const hasValidateModifiedOnlyOption = options &&
-      (typeof options === 'object') &&
-      ('validateModifiedOnly' in options);
+    (typeof options === 'object') &&
+    ('validateModifiedOnly' in options);
 
   const pathsToSkip = (options && options.pathsToSkip) || null;
 
@@ -3014,7 +3017,7 @@ Document.prototype.$__validate = async function $__validate(pathsToValidate, opt
       for (const key in validationError.errors) {
         // Make sure cast errors persist
         if (!this[documentArrayParent] &&
-            validationError.errors[key] instanceof MongooseError.CastError) {
+          validationError.errors[key] instanceof MongooseError.CastError) {
           this.invalidate(key, validationError.errors[key]);
         }
       }
@@ -3132,8 +3135,8 @@ Document.prototype.$__validate = async function $__validate(pathsToValidate, opt
       await schemaType.doValidate(val, scope, doValidateOptions);
     } catch (err) {
       const isSubdoc = schemaType.$isSingleNested ||
-          schemaType.$isArraySubdocument ||
-          schemaType.$isMongooseDocumentArray;
+        schemaType.$isArraySubdocument ||
+        schemaType.$isMongooseDocumentArray;
       if (isSubdoc && err instanceof ValidationError) {
         return;
       }
@@ -3209,7 +3212,7 @@ function _handlePathsToSkip(paths, pathsToSkip) {
  * @api public
  */
 
-Document.prototype.validateSync = function(pathsToValidate, options) {
+Document.prototype.validateSync = function (pathsToValidate, options) {
   const _this = this;
 
   if (arguments.length === 1 && typeof arguments[0] === 'object' && !Array.isArray(arguments[0])) {
@@ -3218,8 +3221,8 @@ Document.prototype.validateSync = function(pathsToValidate, options) {
   }
 
   const hasValidateModifiedOnlyOption = options &&
-      (typeof options === 'object') &&
-      ('validateModifiedOnly' in options);
+    (typeof options === 'object') &&
+    ('validateModifiedOnly' in options);
 
   let shouldValidateModifiedOnly;
   if (hasValidateModifiedOnlyOption) {
@@ -3360,7 +3363,7 @@ Document.prototype.validateSync = function(pathsToValidate, options) {
  * @api public
  */
 
-Document.prototype.invalidate = function(path, err, val, kind) {
+Document.prototype.invalidate = function (path, err, val, kind) {
   if (!this.$__.validationError) {
     this.$__.validationError = new ValidationError(this);
   }
@@ -3396,7 +3399,7 @@ Document.prototype.invalidate = function(path, err, val, kind) {
  * @method $markValid
  */
 
-Document.prototype.$markValid = function(path) {
+Document.prototype.$markValid = function (path) {
   if (!this.$__.validationError || !this.$__.validationError.errors[path]) {
     return;
   }
@@ -3496,7 +3499,7 @@ function _checkImmutableSubpaths(subdoc, schematype, priorVal) {
  * @api private
  */
 
-Document.prototype.$isValid = function(path) {
+Document.prototype.$isValid = function (path) {
   if (this.$__.validationError == null || Object.keys(this.$__.validationError.errors).length === 0) {
     return true;
   }
@@ -3536,7 +3539,7 @@ Document.prototype.$__reset = function reset() {
   }
 
   // clear atomics
-  this.$__dirty().forEach(function(dirt) {
+  this.$__dirty().forEach(function (dirt) {
     const type = dirt.value;
 
     if (type && type[arrayAtomicsSymbol]) {
@@ -3559,7 +3562,7 @@ Document.prototype.$__reset = function reset() {
   this.$__.validationError = undefined;
   this.$errors = undefined;
   _this = this;
-  this.$__schema.requiredPaths().forEach(function(path) {
+  this.$__schema.requiredPaths().forEach(function (path) {
     _this.$__.activePaths.require(path);
   });
 
@@ -3606,9 +3609,9 @@ Document.prototype.$__undoReset = function $__undoReset() {
  * @instance
  */
 
-Document.prototype.$__dirty = function() {
+Document.prototype.$__dirty = function () {
   const _this = this;
-  let all = this.$__.activePaths.map('modify', function(path) {
+  let all = this.$__.activePaths.map('modify', function (path) {
     return {
       path: path,
       value: _this.$__getValue(path),
@@ -3618,7 +3621,7 @@ Document.prototype.$__dirty = function() {
 
   // gh-2558: if we had to set a default and the value is not undefined,
   // we have to save as well
-  all = all.concat(this.$__.activePaths.map('default', function(path) {
+  all = all.concat(this.$__.activePaths.map('default', function (path) {
     if (path === '_id' || _this.$__getValue(path) == null) {
       return;
     }
@@ -3633,7 +3636,7 @@ Document.prototype.$__dirty = function() {
   // Ignore "foo.a" if "foo" is dirty already.
   const minimal = [];
 
-  all.forEach(function(item) {
+  all.forEach(function (item) {
     if (!item) {
       return;
     }
@@ -3650,8 +3653,8 @@ Document.prototype.$__dirty = function() {
     if (top == null) {
       minimal.push(item);
     } else if (top != null &&
-        top[arrayAtomicsSymbol] != null &&
-        top.hasAtomics()) {
+      top[arrayAtomicsSymbol] != null &&
+      top.hasAtomics()) {
       // special case for top level MongooseArrays
       // the `top` array itself and a sub path of `top` are being set.
       // the only way to honor all of both modifications is through a $set
@@ -3673,7 +3676,7 @@ Document.prototype.$__dirty = function() {
  * @instance
  */
 
-Document.prototype.$__setSchema = function(schema) {
+Document.prototype.$__setSchema = function (schema) {
   compile(schema.tree, this, undefined, schema.options);
 
   // Apply default getters if virtual doesn't have any (gh-6262)
@@ -3699,20 +3702,20 @@ Document.prototype.$__setSchema = function(schema) {
  * @instance
  */
 
-Document.prototype.$__getArrayPathsToValidate = function() {
+Document.prototype.$__getArrayPathsToValidate = function () {
   DocumentArray || (DocumentArray = require('./types/documentArray'));
 
   // validate all document arrays.
   return this.$__.activePaths
-    .map('init', 'modify', function(i) {
+    .map('init', 'modify', function (i) {
       return this.$__getValue(i);
     }.bind(this))
-    .filter(function(val) {
+    .filter(function (val) {
       return val && Array.isArray(val) && utils.isMongooseDocumentArray(val) && val.length;
-    }).reduce(function(seed, array) {
+    }).reduce(function (seed, array) {
       return seed.concat(array);
     }, [])
-    .filter(function(doc) {
+    .filter(function (doc) {
       return doc;
     });
 };
@@ -3729,7 +3732,7 @@ Document.prototype.$__getArrayPathsToValidate = function() {
  * @instance
  */
 
-Document.prototype.$getAllSubdocs = function(options) {
+Document.prototype.$getAllSubdocs = function (options) {
   if (options?.useCache && this.$__.saveOptions?.__subdocs) {
     return this.$__.saveOptions.__subdocs;
   }
@@ -3821,7 +3824,7 @@ Document.prototype.$__handleReject = function handleReject(err) {
  * @instance
  */
 
-Document.prototype.$toObject = function(options, json) {
+Document.prototype.$toObject = function (options, json) {
   const defaultOptions = this.$__schema._defaultToObjectOptions(json);
 
   const hasOnlyPrimitiveValues = this.$__hasOnlyPrimitiveValues();
@@ -4141,7 +4144,7 @@ Document.prototype.$__toObjectShallow = function $__toObjectShallow(schemaFields
  * @instance
  */
 
-Document.prototype.toObject = function(options) {
+Document.prototype.toObject = function (options) {
   return this.$toObject(options);
 };
 
@@ -4413,7 +4416,7 @@ function omitDeselectedFields(self, json) {
  * @instance
  */
 
-Document.prototype.toJSON = function(options) {
+Document.prototype.toJSON = function (options) {
   return this.$toObject(options, true);
 };
 
@@ -4421,7 +4424,7 @@ Document.prototype.toJSON = function(options) {
  * ignore
  */
 
-Document.prototype.ownerDocument = function() {
+Document.prototype.ownerDocument = function () {
   return this;
 };
 
@@ -4437,7 +4440,7 @@ Document.prototype.ownerDocument = function() {
  * @instance
  */
 
-Document.prototype.parent = function() {
+Document.prototype.parent = function () {
   if (this.$isSubdocument || this.$__.wasPopulated) {
     return this.$__.parent;
   }
@@ -4467,7 +4470,7 @@ Document.prototype.$parent = Document.prototype.parent;
  * @instance
  */
 
-Document.prototype.inspect = function(options) {
+Document.prototype.inspect = function (options) {
   const isPOJO = utils.isPOJO(options);
   let opts;
   if (isPOJO) {
@@ -4501,7 +4504,7 @@ if (inspect.custom) {
  * @instance
  */
 
-Document.prototype.toString = function() {
+Document.prototype.toString = function () {
   const ret = this.inspect();
   if (typeof ret === 'string') {
     return ret;
@@ -4523,7 +4526,7 @@ Document.prototype.toString = function() {
  * @instance
  */
 
-Document.prototype.equals = function(doc) {
+Document.prototype.equals = function (doc) {
   if (!doc) {
     return false;
   }
@@ -4608,7 +4611,7 @@ Document.prototype.populate = async function populate() {
   if (this.$__isNested) {
     topLevelModel = this.$__[scopeSymbol].constructor;
     const nestedPath = this.$__.nestedPath;
-    paths.forEach(function(populateOptions) {
+    paths.forEach(function (populateOptions) {
       populateOptions.path = nestedPath + '.' + populateOptions.path;
     });
   }
@@ -4683,7 +4686,7 @@ Document.prototype.$getPopulatedDocs = function $getPopulatedDocs() {
  * @api public
  */
 
-Document.prototype.populated = function(path, val, options) {
+Document.prototype.populated = function (path, val, options) {
   // val and options are internal
   if (val == null || val === true) {
     if (!this.$__.populated) {
@@ -4796,7 +4799,7 @@ Document.prototype.$assertPopulated = function $assertPopulated(path, values) {
  * @instance
  */
 
-Document.prototype.depopulate = function(path) {
+Document.prototype.depopulate = function (path) {
   if (typeof path === 'string') {
     path = path.indexOf(' ') === -1 ? [path] : path.split(' ');
   }
@@ -4884,7 +4887,7 @@ Document.prototype.depopulate = function(path) {
  * @instance
  */
 
-Document.prototype.$__fullPath = function(path) {
+Document.prototype.$__fullPath = function (path) {
   // overridden in SubDocuments
   return path || '';
 };
@@ -4930,7 +4933,7 @@ Document.prototype.$__fullPath = function(path) {
  * @instance
  */
 
-Document.prototype.getChanges = function() {
+Document.prototype.getChanges = function () {
   const delta = this.$__delta();
   const changes = delta ? delta[1] : {};
   return changes;
@@ -5101,10 +5104,10 @@ function checkDivergentArray(doc, path, array) {
   // would be similarly destructive as we never received all
   // elements of the array and potentially would overwrite data.
   const check = pop.options.match ||
-      pop.options.options && utils.object.hasOwnProperty(pop.options.options, 'limit') || // 0 is not permitted
-      pop.options.options && pop.options.options.skip || // 0 is permitted
-      pop.options.select && // deselected _id?
-      (pop.options.select._id === 0 ||
+    pop.options.options && utils.object.hasOwnProperty(pop.options.options, 'limit') || // 0 is not permitted
+    pop.options.options && pop.options.options.skip || // 0 is permitted
+    pop.options.select && // deselected _id?
+    (pop.options.select._id === 0 ||
       /\s?-_id\s?/.test(pop.options.select));
 
   if (check) {
@@ -5202,7 +5205,7 @@ function handleAtomics(self, where, delta, data, value) {
   }
 
   if (typeof value.$__getAtomics === 'function') {
-    value.$__getAtomics().forEach(function(atomic) {
+    value.$__getAtomics().forEach(function (atomic) {
       const op = atomic[0];
       const val = atomic[1];
       operand(self, where, delta, data, val, op);
@@ -5284,7 +5287,7 @@ function shouldSkipVersioning(self, path) {
  * @instance
  */
 
-Document.prototype.$clone = function() {
+Document.prototype.$clone = function () {
   const Model = this.constructor;
   const clonedDoc = new Model();
   clonedDoc.$isNew = this.$isNew;
diff --git a/test/schema.test.js b/test/schema.test.js
index 0711b419e4..75816b1d73 100644
--- a/test/schema.test.js
+++ b/test/schema.test.js
@@ -1645,12 +1645,11 @@ describe('schema', function() {
     const Test = mongoose.model('gh3935', testSchema);
     const test = new Test({ test: true });
 
-    assert.ok(test.validateSync());
-    assert.equal(test.validateSync().errors.test.name, 'CastError');
+    const validationResult = test.validateSync();
+    assert.ok(validationResult);
+    assert.equal(validationResult.errors.test.name, 'CastError');
 
 
-  });
-
   it('trim: false works with strings (gh-4042)', function() {
     const testSchema = new Schema({
       test: { type: String, trim: false }