Merge pull request Automattic#12452 from Automattic/Automatticgh-9541

Gh 9541 create mergeDiscriminatorSchema function

lib/helpers/discriminator/mergeDiscriminatorSchema.js

@@ -0,0 +1,63 @@
+'use strict';
+const schemaMerge = require('../schema/merge');
+const specialProperties = require('../../helpers/specialProperties');
+const isBsonType = require('../../helpers/isBsonType');
+const ObjectId = require('../../types/objectid');
+const isObject = require('../../helpers/isObject');
+/**
+ * Merges `from` into `to` without overwriting existing properties.
+ *
+ * @param {Object} to
+ * @param {Object} from
+ * @param {String} [path]
+ * @api private
+ */
+
+module.exports = function mergeDiscriminatorSchema(to, from, path) {
+  const keys = Object.keys(from);
+  let i = 0;
+  const len = keys.length;
+  let key;
+
+  path = path || '';
+
+  while (i < len) {
+    key = keys[i++];
+    if (key === 'discriminators' || key === 'base' || key === '_applyDiscriminators') {
+      continue;
+    }
+    if (path === 'tree' && from != null && from.instanceOfSchema) {
+      continue;
+    }
+    if (specialProperties.has(key)) {
+      continue;
+    }
+    if (to[key] == null) {
+      to[key] = from[key];
+    } else if (isObject(from[key])) {
+      if (!isObject(to[key])) {
+        to[key] = {};
+      }
+      if (from[key] != null) {
+        // Skip merging schemas if we're creating a discriminator schema and
+        // base schema has a given path as a single nested but discriminator schema
+        // has the path as a document array, or vice versa (gh-9534)
+        if ((from[key].$isSingleNested && to[key].$isMongooseDocumentArray) ||
+              (from[key].$isMongooseDocumentArray && to[key].$isSingleNested)) {
+          continue;
+        } else if (from[key].instanceOfSchema) {
+          if (to[key].instanceOfSchema) {
+            schemaMerge(to[key], from[key].clone(), true);
+          } else {
+            to[key] = from[key].clone();
+          }
+          continue;
+        } else if (isBsonType(from[key], 'ObjectID')) {
+          to[key] = new ObjectId(from[key]);
+          continue;
+        }
+      }
+      mergeDiscriminatorSchema(to[key], from[key], path ? path + '.' + key : key);
+    }
+  }
+};

lib/helpers/model/discriminator.js

@@ -4,6 +4,7 @@ const Mixed = require('../../schema/mixed');
 const defineKey = require('../document/compile').defineKey;
 const get = require('../get');
 const utils = require('../../utils');
+const mergeDiscriminatorSchema = require('../../helpers/discriminator/mergeDiscriminatorSchema');
 
 const CUSTOMIZABLE_DISCRIMINATOR_OPTIONS = {
   toJSON: true,
@@ -108,8 +109,7 @@ module.exports = function discriminator(model, name, schema, tiedValue, applyPlu
       }
     }
 
-    utils.merge(schema, baseSchema, {
-      isDiscriminatorSchemaMerge: true,
+    mergeDiscriminatorSchema(schema, baseSchema, {
       omit: { discriminators: true, base: true, _applyDiscriminators: true },
       omitNested: conflictingPaths.reduce((cur, path) => {
         cur['tree.' + path] = true;