fix(instance): make it impossible to save instances without a primary key value …

…(if a primary key is defined), closes #3353

lib/instance.js

@@ -535,6 +535,12 @@ module.exports = (function() {
       }
     }
 
+    if (this.isNewRecord === false) {
+      if (primaryKeyName && !this.get(primaryKeyName, {raw: true})) {
+        throw new Error('You attempted to save an instance with no primary key, this is not allowed since it would result in a global update');
+      }
+    }
+
     return Promise.bind(this).then(function() {
       // Validate
       if (options.validate) {

test/unit/instance/save.test.js

+'use strict';
+
+var chai = require('chai')
+  , expect = chai.expect
+  , Support   = require(__dirname + '/../support')
+  , DataTypes = require(__dirname + '/../../../lib/data-types')
+  , current   = Support.sequelize;
+
+describe(Support.getTestDialectTeaser('Instance'), function() {
+  describe('save', function () {
+    it('should disallow saves if no primary key values is present', function () {
+      var Model = current.define('User', {
+      
+      })
+        , instance;
+
+      instance = Model.build({}, {isNewRecord: false});
+
+      expect(function () {
+        instance.save()
+      }).to.throw();
+    });
+  });
+});
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