Promise-wrapped fails to catch

[ekkis]

I use bluebird with this library:

var neo = require('neo4j');
var Promise = require('bluebird');
var db = new new.GraphDatabase(...);
var cypher = Promise.promisify(db.cypher, {context: db});

but when I issue a request that fails, the code fails to catch it:

cypher('invalid cypher script').catch(e => { console.log('caught'); });

and instead I get a crash like this:

/Users/ekkis/dev/test/inc/node_modules/neo4j/lib-new/errors.js:20 Error.captureStackTrace(this, this.constructor); ^

TypeError: Error.captureStackTrace is not a function at ClientError.Error [as constructor] (/Users/ekkis/dev/test/inc/node_modules/neo4j/lib-new/errors.js:20:13) at new ClientError (/Users/ekkis/dev/test/inc/node_modules/neo4j/lib-new/errors.js:81:48) at Function.__dirname.Error.Error._fromObject (/Users/ekkis/dev/test/inc/node_modules/neo4j/lib-new/errors.js:70:14) at /Users/ekkis/dev/test/inc/node_modules/neo4j/lib-new/GraphDatabase.js:302:25 at Request._callback (/Users/ekkis/dev/test/inc/node_modules/neo4j/lib-new/GraphDatabase.js:92:20) at Request.self.callback (/Users/ekkis/dev/test/inc/node_modules/request/request.js:187:22) at emitTwo (events.js:106:13) at Request.emit (events.js:191:7) at Request. (/Users/ekkis/dev/test/inc/node_modules/request/request.js:1048:10) at emitOne (events.js:96:13) at Request.emit (events.js:188:7) at IncomingMessage. (/Users/ekkis/dev/test/inc/node_modules/request/request.js:969:12) at emitNone (events.js:91:20) at IncomingMessage.emit (events.js:185:7) at endReadableNT (_stream_readable.js:974:12) at _combinedTickCallback (internal/process/next_tick.js:74:11) at process._tickCallback (internal/process/next_tick.js:98:9)

I'm using node v7.3.0 and can't help but thinking it must be related to: https://github.com/thingdom/node-neo4j/issues/211

I need to stop crashing every time the cypher send is malformed. can anyone help?

[ekkis]

ok, to remove the issue of promises I've tested this in a simpler way:

var neo = require('neo4j');
var db = new new.GraphDatabase(...);

and a call with invalid cypher still blows up without returning an error:

db.cypher('invalid cypher script', (err, res) => {
    if (err) console.log('ERROR: ' + err);
    console.log(res);
})

help?

[ekkis]

this is making me crazy. here's a complete test. save the file as "q":

#!/usr/bin/env node

const url = 'http://neo4j:MyPass@localhost:7474';
const Neo4j = require('neo4j');
const db = new Neo4j.GraphDatabase(url);
try {
    db.cypher({query: process.argv[2]}, function(err, ls) {
        console.log('--- CALLBACK ---');
        if (err) {
            console.log('--- ERROR ---');
            console.log(err);
        }
        console.log('--- RESULT ---');
        console.log(ls);
    });
}
catch (e) {
    console.log('--- CAUGHT ---');
    console.log(e);
}

so if I run at the command line:

q "match (n:test) return n"

I get back what I would expect:

--- CALLBACK --- --- RESULT --- [ { n: Node { _id: 0, labels: [Object], properties: [Object] } } ]

but I miss-type the command:

q "match (n:test))) return n"

I see:

/Users/ekkis/Development/x/inc/node_modules/neo4j/lib-new/errors.js:20 Error.captureStackTrace(this, this.constructor); ^

TypeError: Error.captureStackTrace is not a function at ClientError.Error [as constructor] (/Users/ekkis/Development/x/inc/node_modules/neo4j/lib-new/errors.js:20:13) at new ClientError (/Users/ekkis/Development/x/inc/node_modules/neo4j/lib-new/errors.js:81:48) at Function.__dirname.Error.Error._fromObject (/Users/ekkis/Development/x/inc/node_modules/neo4j/lib-new/errors.js:70:14) at /Users/ekkis/Development/x/inc/node_modules/neo4j/lib-new/GraphDatabase.js:302:25 at Request._callback (/Users/ekkis/Development/x/inc/node_modules/neo4j/lib-new/GraphDatabase.js:92:20) at Request.self.callback (/Users/ekkis/Development/x/inc/node_modules/request/request.js:187:22) at emitTwo (events.js:106:13) at Request.emit (events.js:191:7) at Request. (/Users/ekkis/Development/x/inc/node_modules/request/request.js:1048:10) at emitOne (events.js:96:13)

not even the try/catch works! what??

[ekkis]

ok, with the help of jfhbrook from freenode's #node.js I've "fixed" this issue. the library remains broken but for those who care, the exceptions can be caught like this:

process.on('uncaughtException', function(e) {
    console.log('--- CAUGHT BY EVENT ---');
    console.log(e);
});

[ImTheC]

Thanks for the TON of hours of time and frustration you put into looking into this! That "fix" worked for me too to keep the server from crashing completely.

[ghost]

How can we return some value for the API? As catching the unhandled exception works, but unable to return a custom error or text