Added check to prevent multiple commit/rollback on a single transaction

when not using CLS #4491.
Added rollback to prepareEnvironment to abort half-initialized
transactions that run into error, fixes connection pool exhaust bug #4491.

changelog.md

@@ -2,6 +2,7 @@
 - [ADDED] beforeRestore/afterRestore hooks [#4371](https://github.com/sequelize/sequelize/issues/4371)
 - [INTERNALS] `options` has been renamed to `$options` in instance.js [#4429](https://github.com/sequelize/sequelize/pull/4429)
 - [FIXED] Reload doesn't synchronize a null include [#4353](https://github.com/sequelize/sequelize/issues/4353)
+- [FIXED] commit/rollback multiple times on same transaction [#4491](https://github.com/sequelize/sequelize/issues/4491)
 
 # 3.8.0
 - [ADDED] `version` on `Sequelize` returning the current npm/package.json version [#4459](https://github.com/sequelize/sequelize/pull/4459)

lib/transaction.js

@@ -127,6 +127,10 @@ Transaction.LOCK = Transaction.prototype.LOCK = {
 Transaction.prototype.commit = function() {
   var self = this;
 
+  if (this.finished) {
+    throw new Error('Transaction cannot be committed because it has been finished with state: ' + self.finished);
+  }
+
   this.$clearCls();
 
   return this
@@ -150,6 +154,10 @@ Transaction.prototype.commit = function() {
 Transaction.prototype.rollback = function() {
   var self = this;
 
+  if (this.finished) {
+    throw new Error('Transaction cannot be rolled back because it has been finished with state: ' + self.finished);
+  }
+
   this.$clearCls();
 
   return this
@@ -180,6 +188,10 @@ Transaction.prototype.prepareEnvironment = function() {
     return self.setIsolationLevel();
   }).then(function () {
     return self.setAutocommit();
+  }).catch(function (setupErr) {
+    return self.rollback().finally(function () {
+      throw setupErr;
+    });
   }).tap(function () {
     if (self.sequelize.constructor.cls) {
       self.sequelize.constructor.cls.set('transaction', self);

test/integration/transaction.test.js

@@ -134,6 +134,42 @@ describe(Support.getTestDialectTeaser('Transaction'), function() {
     ).to.eventually.be.rejected;
   });
 
+  it('does not allow commits after commit', function () {
+    var self = this;
+    return expect(self.sequelize.transaction().then(function (t) {
+      return t.commit().then(function () {
+        return t.commit();
+      });
+    })).to.be.rejectedWith('Error: Transaction cannot be committed because it has been finished with state: commit');
+  });
+
+  it('does not allow commits after rollback', function () {
+    var self = this;
+    return expect(self.sequelize.transaction().then(function (t) {
+      return t.rollback().then(function () {
+        return t.commit();
+      });
+    })).to.be.rejectedWith('Error: Transaction cannot be committed because it has been finished with state: rollback');
+  });
+
+  it('does not allow rollbacks after commit', function () {
+    var self = this;
+    return expect(self.sequelize.transaction().then(function (t) {
+      return t.commit().then(function () {
+        return t.rollback();
+      });
+    })).to.be.rejectedWith('Error: Transaction cannot be rolled back because it has been finished with state: commit');
+  });
+
+  it('does not allow rollbacks after rollback', function () {
+    var self = this;
+    return expect(self.sequelize.transaction().then(function (t) {
+      return t.rollback().then(function () {
+        return t.rollback();
+      });
+    })).to.be.rejectedWith('Error: Transaction cannot be rolled back because it has been finished with state: rollback');
+  });
+
   if (dialect === 'sqlite'){
     it('provides persistent transactions', function () {
       var sequelize = new Support.Sequelize('database', 'username', 'password', {dialect: 'sqlite'})