fix(hooks): defer applying embedded discriminator hooks until top-level model is compiled

Re: #5706

Author: vkarpov15

lib/schema/documentarray.js

@@ -11,7 +11,6 @@ var EventEmitter = require('events').EventEmitter;
 var MongooseDocumentArray = require('../types/documentarray');
 var SchemaType = require('../schematype');
 var Subdocument = require('../types/embedded');
-var applyHooks = require('../services/model/applyHooks');
 var discriminator = require('../services/model/discriminator');
 var util = require('util');
 var utils = require('../utils');
@@ -120,8 +119,6 @@ DocumentArray.prototype.discriminator = function(name, schema) {
 
   this.casterConstructor.discriminators[name] = EmbeddedDocument;
 
-  applyHooks(EmbeddedDocument, schema);
-
   return this.casterConstructor.discriminators[name];
 };
 

lib/schema/embedded.js

@@ -8,7 +8,6 @@ var $exists = require('./operators/exists');
 var EventEmitter = require('events').EventEmitter;
 var SchemaType = require('../schematype');
 var Subdocument = require('../types/subdocument');
-var applyHooks = require('../services/model/applyHooks');
 var castToNumber = require('./operators/helpers').castToNumber;
 var discriminator = require('../services/model/discriminator');
 var geospatial = require('./operators/geospatial');
@@ -255,7 +254,5 @@ Embedded.prototype.discriminator = function(name, schema) {
 
   this.caster.discriminators[name] = _createConstructor(schema);
 
-  applyHooks(this.caster.discriminators[name], schema);
-
   return this.caster.discriminators[name];
 };

lib/services/model/applyHooks.js

@@ -24,10 +24,18 @@ function applyHooks(model, schema) {
 
   model.$appliedHooks = true;
   for (i = 0; i < schema.childSchemas.length; ++i) {
-    if (schema.childSchemas[i].model.$appliedHooks) {
+    var childModel = schema.childSchemas[i].model;
+    if (childModel.$appliedHooks) {
       continue;
     }
-    applyHooks(schema.childSchemas[i].model, schema.childSchemas[i].schema);
+    if (childModel.discriminators != null) {
+      keys = Object.keys(childModel.discriminators);
+      for (j = 0; j < keys.length; ++j) {
+        applyHooks(childModel.discriminators[keys[j]],
+          childModel.discriminators[keys[j]].schema);
+      }
+    }
+    applyHooks(childModel, schema.childSchemas[i].schema);
   }
 
   if (!q.length) {