Transactions causing - Warning: a promise was created in a handler but was not returned from it

Yuval Kaplan

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Jan 4, 2016, 12:28:33 PM1/4/16

to Sequelize

Hi,

I have the following code:


return sequelize.transaction(function (t) {
   return new Promise(function(resolve, reject) {
     return resolve("OK");
   });
})
.then(function(result) {
   console.log(result);
})
.catch(function(err) {
   console.log(err);
});

I get the following warning:


Warning: a promise was created in a handler but was not returned from it
    at ConnectionManager.releaseConnection (/home/yuval/myapp/node_modules/sequelize/lib/dialects/abstract/connection-manager.js:253:10)
    at Transaction.cleanup (/home/yuval/myapp/node_modules/sequelize/lib/transaction.js:278:46)
    at /home/yuval/myapp/node_modules/sequelize/lib/transaction.js:188:14
From previous event:
    at Promise.finally (/home/yuval/myapp/node_modules/sequelize/lib/promise.js:21:17)
    at Transaction.commit (/home/yuval/myapp/node_modules/sequelize/lib/transaction.js:185:13)
    at /home/yuval/myapp/node_modules/sequelize/lib/sequelize.js:1237:30
From previous event:
    at Promise.then (/home/yuval/myapp/node_modules/sequelize/lib/promise.js:21:17)
    at Sequelize.transaction.transactionResolver (/home/yuval/myapp/node_modules/sequelize/lib/sequelize.js:1228:40)
From previous event:
    at Sequelize.transaction (/home/yuval/myapp/node_modules/sequelize/lib/sequelize.js:1257:12)
    at self.testOrm (/home/yuval/myapp/source/main.js:186:30)
    at /home/yuval/myapp/source/main.js:232:17
    at processImmediate [as _immediateCallback] (timers.js:374:17)
From previous event:
    at Promise.then (/home/yuval/myapp/node_modules/sequelize/lib/promise.js:21:17)
    at self.setupAndStart (/home/yuval/myapp/source/main.js:231:5)
    at /home/yuval/myapp/server.js:11:7
    at Object.context.execCb (/home/yuval/myapp/node_modules/requirejs/bin/r.js:1929:33)
    at Object.Module.check (/home/yuval/myapp/node_modules/requirejs/bin/r.js:1129:51)
    at Object.Module.enable (/home/yuval/myapp/node_modules/requirejs/bin/r.js:1416:22)
    at Object.Module.init (/home/yuval/myapp/node_modules/requirejs/bin/r.js:1034:26)
    at null._onTimeout (/home/yuval/myapp/node_modules/requirejs/bin/r.js:1692:36)
    at Timer.listOnTimeout (timers.js:89:15)

With Sequelize logging turned on I get the following log output before I get the above warning:


Executing (d60ae591-6d3a-47a0-aae9-b54db4b2e172): START TRANSACTION;
Executing (d60ae591-6d3a-47a0-aae9-b54db4b2e172): SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ;
Executing (d60ae591-6d3a-47a0-aae9-b54db4b2e172): SET autocommit = 1;
Executing (d60ae591-6d3a-47a0-aae9-b54db4b2e172): COMMIT;

I think this is as basic as it gets and the transaction seems to be working correctly so I am not sure what I am doing wrong.

If I run a simple Promise or any other Sequelize call (find, update, create) without the transaction it does not show this warning.

It would be really helpful if anyone can spot what I am doing wrong.

Thanks!

Yuval Kaplan

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Jan 4, 2016, 12:40:46 PM1/4/16

to Sequelize

Just to makes things a little bit more readable. If I place the code section after I create the sequelize instance and then run the code, I get the following warning:

Warning: a promise was created in a handler but was not returned from it                                                                                                                                                               
    at ConnectionManager.releaseConnection (/home/yuval/myapp/node_modules/sequelize/lib/dialects/abstract/connection-manager.js:253:10)                                                                                             
    at Transaction.cleanup (/home/yuval/myapp/node_modules/sequelize/lib/transaction.js:278:46)                                                                                                                                      
    at /home/yuval/myapp/node_modules/sequelize/lib/transaction.js:188:14

                                                                                                                                                            
    at processImmediate [as _immediateCallback] (timers.js:374:17)                                                                                                                                                                          
From previous event:                                                                                                                                                                                                                        
    at Promise.finally (/home/yuval/myapp/node_modules/sequelize/lib/promise.js:21:17)                                                                                                                                               
    at Transaction.commit (/home/yuval/myapp/node_modules/sequelize/lib/transaction.js:185:13)                                                                                                                                      
    at /home/yuval/myapp/node_modules/sequelize/lib/sequelize.js:1237:30

All the rest is the same.

Mick Hansen

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Jan 5, 2016, 2:47:06 AM1/5/16

to Yuval Kaplan, Sequelize

Known issue after we upgraded Bluebird, trying to find out where its originating.

--

Mick Hansen

@mhansendev
mhansen.io

Yuval Kaplan

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Jan 5, 2016, 4:08:04 AM1/5/16

to Sequelize, yuva...@gmail.com

Thanks Mick.

Any open issue I can follow to get an update on when this gets fixed?

Mick Hansen

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Jan 5, 2016, 4:15:23 AM1/5/16

to Yuval Kaplan, Sequelize

There's an issue on github somewhere, but it's sort of an ongoing process since we're not totally sure where it's happening.

Bondi French

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Mar 17, 2016, 6:23:23 PM3/17/16

to Sequelize, yuva...@gmail.com

I have the same error with MS SQL and Sequelize 3.19.3, here is the error I got:

Warning: a promise was created in a handler but was not returned from it

at processImmediate [as _immediateCallback] (timers.js:383:17)

From previous event:

at Model.findAll (c:\Users\London\Apps\FinviewsApp\node_modules\Sequelize\lib\model.js:1343:18)

at c:\Users\London\Apps\FinviewsApp\routes\api.js:486:16

at Layer.handle [as handle_request] (c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\layer.js:76:5)

at next (c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\route.js:100:13)

at Route.dispatch (c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\route.js:81:3)

at Layer.handle [as handle_request] (c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\layer.js:76:5)

at c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\index.js:234:24

at Function.proto.process_params (c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\index.js:312:12)

at c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\index.js:228:12

at Function.match_layer (c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\index.js:295:3)

at next (c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\index.js:189:10)

at c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\index.js:191:16

at Function.match_layer (c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\index.js:295:3)

at next (c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\index.js:189:10)

at c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\index.js:191:16

at Function.match_layer (c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\index.js:295:3)

at next (c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\index.js:189:10)

at c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\index.js:191:16

From previous event:

at Promise.then (c:\Users\London\Apps\FinviewsApp\node_modules\Sequelize\lib\promise.js:21:17)

at c:\Users\London\Apps\FinviewsApp\config\passport.js:21:5

at pass (c:\Users\London\Apps\FinviewsApp\node_modules\passport\lib\authenticator.js:353:9)

at Authenticator.deserializeUser (c:\Users\London\Apps\FinviewsApp\node_modules\passport\lib\authenticator.js:358:5)

at SessionStrategy.authenticate (c:\Users\London\Apps\FinviewsApp\node_modules\passport\lib\strategies\session.js:49:

at attempt (c:\Users\London\Apps\FinviewsApp\node_modules\passport\lib\middleware\authenticate.js:341:16)

at authenticate (c:\Users\London\Apps\FinviewsApp\node_modules\passport\lib\middleware\authenticate.js:342:7)

at Layer.handle [as handle_request] (c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\layer.js:76:5)

at trim_prefix (c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\index.js:270:13)

at c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\index.js:237:9

at Function.proto.process_params (c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\index.js:312:12)

at c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\index.js:228:12

at Function.match_layer (c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\index.js:295:3)

at next (c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\index.js:189:10)

at initialize (c:\Users\London\Apps\FinviewsApp\node_modules\passport\lib\middleware\initialize.js:62:5)

at Layer.handle [as handle_request] (c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\layer.js:76:5)

at trim_prefix (c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\index.js:270:13)

at c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\index.js:237:9

at Function.proto.process_params (c:\Users\London\Apps\FinviewsApp\node_modules\express\lib\router\index.js:312:12)

Mick Hansen

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Mar 18, 2016, 5:13:35 AM3/18/16

to Bondi French, Sequelize, Yuval Kaplan

It's almost always in the userside code. It can disabled with a bluebird environment variable.

http://bluebirdjs.com/docs/warning-explanations.html#warning-a-promise-was-created-in-a-handler-but-none-were-returned-from-it
http://bluebirdjs.com/docs/api/environment-variables.html

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