Merge branch '6.2' of github.com:Automattic/mongoose into 6.2

lib/helpers/model/discriminator.js

@@ -17,6 +17,7 @@ const CUSTOMIZABLE_DISCRIMINATOR_OPTIONS = {
  */
 
 module.exports = function discriminator(model, name, schema, tiedValue, applyPlugins) {
+
   if (!(schema && schema.instanceOfSchema)) {
     throw new Error('You must pass a valid discriminator Schema');
   }
@@ -201,7 +202,7 @@ module.exports = function discriminator(model, name, schema, tiedValue, applyPlu
 
   model.schema.discriminators[name] = schema;
 
-  if (model.discriminators[name]) {
+  if (model.discriminators[name] && !schema.options.overwriteModels) {
     throw new Error('Discriminator with name "' + name + '" already exists');
   }
 

lib/model.js

@@ -1134,11 +1134,13 @@ Model.exists = function exists(filter, options, callback) {
  * @param {Object|String} [options] If string, same as `options.value`.
  * @param {String} [options.value] the string stored in the `discriminatorKey` property. If not specified, Mongoose uses the `name` parameter.
  * @param {Boolean} [options.clone=true] By default, `discriminator()` clones the given `schema`. Set to `false` to skip cloning.
+ * @param {Boolean} [options.overwriteModels=false] by default, Mongoose does not allow you to define a discriminator with the same name as another discriminator. Set this to allow overwriting discriminators with the same name.
  * @return {Model} The newly created discriminator model
  * @api public
  */
 
 Model.discriminator = function(name, schema, options) {
+
   let model;
   if (typeof name === 'function') {
     model = name;
@@ -1162,7 +1164,7 @@ Model.discriminator = function(name, schema, options) {
   }
 
   schema = discriminator(this, name, schema, value, true);
-  if (this.db.models[name]) {
+  if (this.db.models[name] && !schema.options.overwriteModels) {
     throw new OverwriteModelError(name);
   }
 

test/model.discriminator.test.js

@@ -1867,4 +1867,24 @@ describe('model', function() {
     assert.equal(res.c.gc.gc11, 'eleventy');
     assert.equal(res.c.gc.gc12, 110);
   });
+  it('Should allow reusing discriminators (gh-10931)', async function() {
+    const options = { discriminatorKey: 'kind', overwriteModels: true };
+    const eventSchema = new mongoose.Schema({ time: Date }, options);
+    const Event = db.model('Event', eventSchema);
+
+    const ClickedLinkEvent = Event.discriminator('ClickedLink',
+      new mongoose.Schema({ url: String }, options));
+    const reUse = Event.discriminator('ClickedLink', new mongoose.Schema({ url: String }, options));
+    assert.ok(reUse);
+
+
+    const genericEvent = new Event({ time: Date.now(), url: 'google.com' });
+    assert.ok(!genericEvent.url);
+
+    const clickedEvent = new ClickedLinkEvent({ time: Date.now(), url: 'google.com' });
+    assert.ok(clickedEvent.url);
+
+    const reUseEvent = new reUse({ time: Date.now(), url: 'test.com' });
+    assert.ok(reUseEvent.url);
+  });
 });