app.render callbacks twice

[AtsushiSuzuki]

app.render method with callback sometimes callbacks twice, if callback throws exception.

var app = express();
app.set('view engine', 'ejs');

var called = 0;
app.render(__dirname + '/template.ejs', function (err, body) {
  console.log('called: ', ++called);
  throw new Error('some error');
});

Express.js: 4.12.4
ejs: 2.3.1
Node.js: 0.12.2

[dougwilson]

Thanks for the report! This is a bug in the ejs library because their __express export is not async as we require. You can report the bug to ejs at https://github.com/mde/ejs

[dougwilson]

What I can do is put down for Express 5.0 that we will make res.render always be async, even if the view engine you are using is violating our interface and executing the callback sync.

[AtsushiSuzuki]

Thank you for reply.
I'm looking forward for 5.0.

[dougwilson]

Ok, this has been integrated in the 5.0 branch and published as part of the 5.0.0-alpha.2 release!