Pg-promise: Unhandled promise rejection

[italodeandra]

(node:10716) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 2): Error: getaddrinfo ENOTFOUND
(node:10716) DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

I'm using the wrong host to test error handling, and this came up.
How can I avoid that? I'm using Node 7 Async/Await like this:

async function selecionarFeriadoPorId(params) {
    return db.func('Administracao.SelecionarFeriadoPorId', [
        params.idSistema,
        params.id
    ]);
}

[vitaly-t]

That means your query fails, and you are not providing any .catch handler (regular catch in case of ES7 await/async).

See also: http://stackoverflow.com/questions/40500490/what-is-unhandled-promise-rejection

Basically, this is a generic promise-misuse issue, not an issue with this library ;)

[italodeandra]

I used try catch and still doesn't "work", I traced the exception and it is unhandled because you have a line on your code that is preventing of throwing.
Still, I think you should be more polite when talking to people who uses your library. Or maybe don't answer if you don't want to help.

Thank you.

[vitaly-t]

I used try catch and still doesn't "work", I traced the exception and it is unhandled because you have a line on your code that is preventing of throwing.

You provided none of the details to that end. And I gave you the right answer for the details that you did provide.

I think you should be more polite when talking to people who uses your library. Or maybe don't answer if you don't want to help

Really? I fail to see how. But If you feel that way, then seek help elsewhere.

P.S. Your code looks wrong also, instead of return db.func( there should be return await db.func(.

[pshemk]

Hi,

I seem to have the same problem, the following sequence causes it:

const productInstanceCreate = async (req) => {

    var instanceId;
    var customerId;

    try {
        //check if we have a customer with this name, if not create one
        customerId = (await db.oneOrNone("SELECT customer_id FROM customer WHERE name=$1", [req.params.customer])).customer_id;
        log.debug("productInstanceCreate: customerId: %s", JSON.stringify(customerId, null, 1));
        return customerId;
    } catch (e) {
        log.error("productInstanceCreate: error: %s", JSON.stringify(e, null, 1));
        throw new Error("productInstanceCreate: error: %s", e);
    }

That 'catch' there doesn't see an error thrown, but if I setup a handler for an unhandled rejection I can trap it (but since at that stage it has not context I can't do much with it):

process.on("unhandledRejection", (reason, p) => {
    log.error("Unhadled Rejection at: %s, reason: %s", reason, p);
});

I get this (some output omitted):

[2017-06-26T01:49:42.255Z] DEBUG: instance-inventory-api/14349 on backend: productInstanceCreate: customerId: undefined
[2017-06-26T01:49:42.273Z] ERROR: instance-inventory-api/14349 on backend:
    Unhadled Rejection at: QueryResultError {
        code: queryResultErrorCode.multiple
        message: "Multiple rows were not expected."
        received: 5
        query: "SELECT customer_id FROM customer WHERE name='customer name2'"
    }, reason: [object Promise]

[vitaly-t]

@pshemk the code you showed cannot produce that type of problem. I have tried, but cannot reproduce, the rejection is always handled by .catch() correctly.

const test = async () => {
    try {
        const res = (await db.oneOrNone('select * from users where id > $1', [1])).id;
    } catch (error) {
        console.log('CAUGHT:', error); // always gets here
    }
};

What is your complete environment? -

• Node.js version?
• pg-promise version?
• OS?

[pshemk]

I'm struggling to reliably replicate this myself. Using a simple snipped like that it works reliably, so it must be my code :-)

node.js: 8.1.2
pg-promise: 6.1.0
os: ubuntu 16.04.2

I'll update this issue if I manage to get a reliable way of replicating the problem.

[vitaly-t]

@pshemk ok, if you can get the steps for this, get back to me. Otherwise, I cannot reproduce it from the example given earlier.

[vitaly-t]

@pshemk Try proper error stack tracing, so that way you at least can post it here, if you ever reproduce the issue:

const promise = require('bluebird');

promise.config({
    longStackTraces: true // enable Long-Stack Traces
});

const pgp = require('pg-promise')({
    promiseLib: promise
});