Fix sequelize.transaction() breaks when used with Promise.mapSeries (#5943) (#6319)

lib/promise.js

@@ -33,10 +33,12 @@ shimCLS(Promise.prototype, 'finally', [0]);
 
 // Collections
 shimCLS(Promise, 'map', [1]);
+shimCLS(Promise, 'mapSeries', [1]);
 shimCLS(Promise, 'reduce', [1]);
 shimCLS(Promise, 'filter', [1]);
 shimCLS(Promise, 'each', [1]);
 shimCLS(Promise.prototype, 'map', [0]);
+shimCLS(Promise.prototype, 'mapSeries', [0]);
 shimCLS(Promise.prototype, 'reduce', [0]);
 shimCLS(Promise.prototype, 'filter', [0]);
 shimCLS(Promise.prototype, 'each', [0]);

test/integration/cls.test.js

@@ -256,6 +256,30 @@ if (current.dialect.supports.transactions) {
         });
       });
 
+      it('mapSeries', function () {
+        var self = this;
+        return this.sequelize.transaction(function () {
+          var tid = self.ns.get('transaction').id;
+          return self.User.findAll().mapSeries(function () {
+            expect(self.ns.get('transaction').id).to.be.ok;
+            expect(self.ns.get('transaction').id).to.equal(tid);
+          });
+        });
+      });
+
+      it('static mapSeries', function () {
+        var self = this;
+        return this.sequelize.transaction(function () {
+          var tid = self.ns.get('transaction').id;
+          // In order to execute promises serially with mapSeries we must wrap them as functions
+          return self.sequelize.Promise.mapSeries([
+              ()=> self.User.findAll().then(()=> expect(self.ns.get('transaction').id).to.be.ok),
+              ()=> self.User.findAll().then(()=> expect(self.ns.get('transaction').id).to.equal(tid))
+            ], runPromise => runPromise()
+          );
+        });
+      });
+
       it('reduce', function () {
         var self = this;
         return this.sequelize.transaction(function () {