Polymorphic lookup from all registered dataSources

Polymorphic model lookup was previously limited to the same dataSource
as the modelFrom model, which turns out to be too restrictive. This was
uncovered by the use of a Transient model, not being able to lookup a
PersistedModel.

index.js

@@ -4,6 +4,12 @@ exports.ModelBaseClass = require('./lib/model.js');
 exports.GeoPoint = require('./lib/geo.js').GeoPoint;
 exports.ValidationError = require('./lib/validations.js').ValidationError;
 
+var dataSources = exports.dataSources = {};
+
+exports.registerDataSource = function(ds) {
+  dataSources[ds.name] = ds;
+};
+
 exports.__defineGetter__('version', function () {
     return require('./package.json').version;
 });

lib/relation-definition.js

@@ -4,6 +4,7 @@
 var assert = require('assert');
 var util = require('util');
 var i8n = require('inflection');
+var jdb = require('../');
 var defineScope = require('./scope.js').defineScope;
 var mergeQuery = require('./scope.js').mergeQuery;
 var ModelBaseClass = require('./model.js');
@@ -466,7 +467,7 @@ function findBelongsTo(modelFrom, modelTo, keyTo) {
  * @param {String} modelName The model name
  * @returns {*} The matching model class
  */
-function lookupModel(models, modelName) {
+function lookupModel(models, modelName, internal) {
   if(models[modelName]) {
     return models[modelName];
   }
@@ -476,6 +477,15 @@ function lookupModel(models, modelName) {
       return models[name];
     }
   }
+  if (internal) return;
+  
+  var keys = Object.keys(jdb.dataSources);
+  for (var k = 0; k < keys.length; k++) {
+    var ds = jdb.dataSources[keys[k]];
+    var models = ds.modelBuilder.models;
+    var model = lookupModel(models, modelName, true);
+    if (model) return model;
+  }
 }
 
 function lookupModelTo(modelFrom, modelTo, params, singularize) {
@@ -503,9 +513,9 @@ function lookupModelTo(modelFrom, modelTo, params, singularize) {
  * @param {Object|String} params Name of the polymorphic relation or params
  * @returns {Object} The normalized parameters
  */
-function polymorphicParams(params) {
+function polymorphicParams(params, as) {
   if (typeof params === 'string') params = { as: params };
-  if (typeof params.as !== 'string') params.as = 'reference'; // default
+  if (typeof params.as !== 'string') params.as = as || 'reference'; // default
   params.foreignKey = params.foreignKey || i8n.camelize(params.as + '_id', true);
   params.discriminator = params.discriminator || i8n.camelize(params.as + '_type', true);
   return params;
@@ -1079,21 +1089,23 @@ RelationDefinition.belongsTo = function (modelFrom, modelTo, params) {
 
   var idName, relationName, fk;
   if (params.polymorphic) {
+    relationName = params.as || (typeof modelTo === 'string' ? modelTo : null); // initially
+    
     if (params.polymorphic === true) {
       // modelTo arg will be the name of the polymorphic relation (string)
-      polymorphic = polymorphicParams(modelTo);
+      polymorphic = polymorphicParams(modelTo, relationName);
     } else {
-      polymorphic = polymorphicParams(params.polymorphic);
+      polymorphic = polymorphicParams(params.polymorphic, relationName);
     }
     
     modelTo = null; // will lookup dynamically
     
     idName = params.idName || 'id';
-    relationName = params.as || polymorphic.as;
+    relationName = params.as || polymorphic.as; // finally
     fk = polymorphic.foreignKey;
     discriminator = polymorphic.discriminator;
     
-    if (typeof polymorphic.idType === 'string') { // explicit key type
+    if (polymorphic.idType) { // explicit key type
       modelFrom.dataSource.defineProperty(modelFrom.modelName, fk, { type: polymorphic.idType, index: true });
     } else { // try to use the same foreign key type as modelFrom
       modelFrom.dataSource.defineForeignKey(modelFrom.modelName, fk, modelFrom.modelName);
@@ -2208,10 +2220,7 @@ EmbedsMany.prototype.build = function(targetModelData) {
   
   var assignId = (forceId || targetModelData[pk] === undefined);
   
-  if (assignId && typeof connector.generateId === 'function') {
-    var id = connector.generateId(modelTo.modelName, targetModelData, pk);
-    targetModelData[pk] = id;
-  } else if (assignId && pkType === Number) {
+  if (assignId && pkType === Number) {
     var ids = embeddedList.map(function(m) { 
       return (typeof m[pk] === 'number' ? m[pk] : 0);
     });
@@ -2220,6 +2229,9 @@ EmbedsMany.prototype.build = function(targetModelData) {
     } else {
       targetModelData[pk] = 1;
     }
+  } else if (assignId && typeof connector.generateId === 'function') {
+      var id = connector.generateId(modelTo.modelName, targetModelData, pk);
+      targetModelData[pk] = id;
   }
   
   this.definition.applyProperties(modelInstance, targetModelData);

test/relations.test.js

@@ -1,6 +1,7 @@
 // This test written in mocha+should.js
 var should = require('./init.js');
-var Schema = require('../').Schema;
+var jdb = require('../');
+var Schema = jdb.Schema;
 
 var db, tmp, Book, Chapter, Author, Reader;
 var Category, Job;
@@ -2420,11 +2421,20 @@ describe('relations', function () {
     
     before(function (done) {
       db = getSchema();
+      tmp = getTransientSchema();
+      
+      // register here, so transient models
+      // can lookup related models (polymorphic)
+      jdb.registerDataSource(db);
+      
       Book = db.define('Book', {name: String});
       Author = db.define('Author', {name: String});
       Reader = db.define('Reader', {name: String});
       
-      Link = db.define('Link', {name: String, notes: String}); // generic model
+      Link = tmp.define('Link', {
+        id: {type: Number, id: true},
+        name: String, notes: String
+      }); // generic model
       Link.validatesPresenceOf('linkedId');
       Link.validatesPresenceOf('linkedType');
 
@@ -2438,13 +2448,15 @@ describe('relations', function () {
     });
 
     it('can be declared', function (done) {
+      var idType = db.connector.getDefaultIdType();
+      
       Book.embedsMany(Link, { as: 'people',
         polymorphic: 'linked',
         scope: { include: 'linked' }
       });      
       Link.belongsTo('linked', {
-        polymorphic: true, // needs unique auto-id
-        properties: { name: 'name' }, // denormalized
+        polymorphic: { idType: idType },  // native type
+        properties: { name: 'name' },     // denormalized
         options: { invertProperties: true }
       });
       db.automigrate(done);