write test, begin debug

lib/cast.js

@@ -61,6 +61,7 @@ module.exports = function cast(schema, obj, options, context) {
     val = obj[path];
 
     if (path === '$or' || path === '$nor' || path === '$and') {
+      console.log('what is val', val);
       if (!Array.isArray(val)) {
         throw new CastError('Array', val, path);
       }
@@ -303,7 +304,6 @@ module.exports = function cast(schema, obj, options, context) {
         } else {
           const ks = Object.keys(val);
           let $cond;
-
           let k = ks.length;
 
           while (k--) {
@@ -367,6 +367,8 @@ module.exports = function cast(schema, obj, options, context) {
 
         obj[path] = { $in: casted };
       } else {
+        console.log('Houston we have a problem.');
+        console.log('what is obj[path]', obj[path], path, obj, val);
         obj[path] = schematype.castForQuery(
           null,
           val,

lib/schematype.js

@@ -1186,6 +1186,7 @@ SchemaType.prototype._applySetters = function(value, scope, init, priorVal, opti
   const setters = this.setters;
 
   for (let i = setters.length - 1; i >= 0; i--) {
+    console.log('what is v', v, setters.length);
     v = setters[i].call(scope, v, priorVal, this, options);
   }
 
@@ -1215,7 +1216,6 @@ SchemaType.prototype.applySetters = function(value, scope, init, priorVal, optio
   if (v == null) {
     return this._castNullish(v);
   }
-
   // do not cast until all setters are applied #665
   v = this.cast(v, scope, init, priorVal, options);
 

test/model.discriminator.test.js

@@ -2180,4 +2180,34 @@ describe('model', function() {
     assert.ok(innerBuildingsPath.schemaOptions.type.discriminators.Garage);
     assert.equal(innerBuildingsPath.schemaOptions.type.discriminators.Garage.discriminatorMapping.value, 'G');
   });
+  it('should not fail when using a discriminator key multiple times (gh-13906)', async function() {
+    const options = { discriminatorKey: 'type' };
+    const eventSchema = new Schema({ date: Schema.Types.Date }, options);
+    const Event = db.model('gh-13906-event', eventSchema);
+
+
+    const clickedLinkEventSchema = new Schema({ url: String }, options);
+    const ClickedLinkEvent = Event.discriminator('ClickedLinkEvent', clickedLinkEventSchema, 'clickedLinkEvent');
+
+
+    const clickedImageEventSchema = new Schema({ image: String }, options);
+    const ClickedImageEvent = Event.discriminator('ClickedImageEvent', clickedImageEventSchema, 'clickedImageEvent');
+
+    const clickedLinkEvent = new ClickedLinkEvent({ url: 'https://clicked-link.com' });
+    assert.equal(clickedLinkEvent.type, 'clickedLinkEvent');
+    assert.equal(clickedLinkEvent.url, 'https://clicked-link.com');
+
+    const clickedImageEvent = new ClickedImageEvent({ image: 'clicked-image.png' });
+    assert.equal(clickedImageEvent.type, 'clickedImageEvent');
+    assert.equal(clickedImageEvent.image, 'clicked-image.png');
+    const query = {
+      type: 'clickedLinkEvent',
+      $or: [
+        { type: 'clickedImageEvent' }
+      ]
+    };
+    const result = await Event.find(query).exec();
+    assert(result);
+
+  });
 });