TypeError: Cannot read property 'substr' of undefined

[jamesdixon]

Loaded cute-stack programmatically and seeing the following when starting my server:

/Users/jamesdixon/Projects/scout/platform/api/node_modules/cute-stack/index.js:162
        .substr(0, col)
        ^

TypeError: Cannot read property 'substr' of undefined

.♦cute-stack/index.js  162,9
module.js  385,24   Module._compile
module.js  422,10   Module._extensions..js
module.js  357,32   Module.load
module.js  314,12   Module._load
module.js  367,17   Module.require
internal/module.js  16,19   require
.♦knex/lib/client.js  8,14   function (exports, require, module, __filename, __dirname) { [body] }
module.js  413,34   Module._compile
module.js  422,10   Module._extensions..js
module.js  357,32   Module.load
module.js  314,12   Module._load
module.js  367,17   Module.require
internal/module.js  16,19   require
.♦knex/lib/index.js  5,14   function (exports, require, module, __filename, __dirname) { [body] }
module.js  413,34   Module._compile

Note that the stack trace is formatted nicely, but obviously it crashes.

[davidmarkclements]

@jamesdixon can you give me your node version?

[jamesdixon]

5.10.1

[davidmarkclements]

@jamesdixon can you give me some sample code to check this against, I can't reproduce

[jamesdixon]

I'll try and get you something soon, but it may be a while 😄

[bahmutov]

Most likely the "line" variable is invalid index into the source list in https://github.com/davidmarkclements/cute-stack/blob/master/index.js#L161 thus .substr is called on the undefined

[davidmarkclements]

hey @bahmutov (hows things!) - yes I had the same thought, but I'd like to know what's causing that and why - I'm hesitant to bandaid it in case that just pushes the issue elsewhere

[bahmutov]

Hi (very busy)! Yeah, it would be nice to actually see the failing code before protecting against it

[jamesdixon]

Sorry, gents. If it was a simple copy/paste, then I would take care of it immediately, but it's failing in a large, private project.

I can tell you that I'm using Hapi.js and simply calling require('cute-stack')(); at the beginning of my script that starts the server.

[jamesdixon]

I did some simple console.log debugging and it appears that @bahmutov is correct. line does appear to be an invalid index, which returns undefined and then subsequently fails when substr is called on it.

[davidmarkclements]

Is there any on the fly transpilation or source rewriting or anything going after you require cute-stack?

The issue is we do a frame.getLineNumber() - that's a v8 call, that gives us a corresponding line number for that particular frame in the callstack.

To get the script source, which we're applying the line number to, we overwrite the internal Module.wrap function require('module') get's the internal Module constructor

So is there anything else in the code that's modifying scripts on the way through the module loading process?

Another thing to try, is to get a complete stack trace by setting Error.stackTraceLimit = Infinity

[davidmarkclements]

also: try requiring cute-stack at the end of the server start script

[jamesdixon]

Here's the full stack trace:

/Users/jamesdixon/Projects/scout/platform/api/node_modules/cute-stack/index.js:162
        .substr(0, col)
        ^

TypeError: Cannot read property 'substr' of undefined

.♦cute-stack/index.js  162,9
module.js  385,24   Module._compile
module.js  422,10   Module._extensions..js
module.js  357,32   Module.load
module.js  314,12   Module._load
module.js  367,17   Module.require
internal/module.js  16,19   require
.♦knex/lib/client.js  8,14   function (exports, require, module, __filename, __dirname) { [body] }
module.js  413,34   Module._compile
module.js  422,10   Module._extensions..js
module.js  357,32   Module.load
module.js  314,12   Module._load
module.js  367,17   Module.require
internal/module.js  16,19   require
.♦knex/lib/index.js  5,14   function (exports, require, module, __filename, __dirname) { [body] }
module.js  413,34   Module._compile
module.js  422,10   Module._extensions..js
module.js  357,32   Module.load
module.js  314,12   Module._load
module.js  367,17   Module.require
internal/module.js  16,19   require
.♦knex/knex.js  8,18   function (exports, require, module, __filename, __dirname) { [body] }
module.js  413,34   Module._compile
module.js  422,10   Module._extensions..js
module.js  357,32   Module.load
module.js  314,12   Module._load
module.js  367,17   Module.require
internal/module.js  16,19   require
./config/bookshelf.js  7,14   function (exports, require, module, __filename, __dirname) { [body] }
module.js  413,34   Module._compile
module.js  422,10   Module._extensions..js
module.js  357,32   Module.load
module.js  314,12   Module._load
module.js  367,17   Module.require
internal/module.js  16,19   require
./config/config.js  8,19   function (exports, require, module, __filename, __dirname) { [body] }
module.js  413,34   Module._compile
module.js  422,10   Module._extensions..js
module.js  357,32   Module.load
module.js  314,12   Module._load
module.js  367,17   Module.require
internal/module.js  16,19   require
./server.js  25,18   module.exports.Glue.compose.then
./start.js  5,35   function (exports, require, module, __filename, __dirname) { [body] }
module.js  413,34   Module._compile
module.js  422,10   Module._extensions..js
module.js  357,32   Module.load
module.js  314,12   Module._load
module.js  447,10   Module.runMain
node.js  146,18   startup
node.js  404,3

As for anything modifying scripts, there's nothing that I'm aware of. No Babel transpilation or anything of that sort.

[jamesdixon]

Just tried adding the require after my server starts and that works!

[jamesdixon]

I believe I've narrowed down where the problem occurs based on that stack trace. It appears something happens with Glue that's causing the crash to occur. Here's my code for server.js:

Glue
        .compose(require('./config/config'), options)
        .then((server) => {

            // register rollbar to report uncaught exceptions
            if (isProductionLike) {
                server.plugins.icecreambar.default.handleUncaughtExceptions(process.env.ROLLBAR_ACCESS_TOKEN, {
                    exitOnUncaughtException: true
                });
            }

            // setup authentication strategy
            server.auth.strategy('jwt', 'jwt', 'required', {
                key: process.env.JWT_SECRET,
                validateFunc: require('./utils/auth/validateToken'),
                verifyOptions: {
                    algorithms: ['HS256']
                }
            });

            // register routes
            server.select('business-api').route(require('./routes/business').routes);

            return server;
        })
        .catch((err) => {

            console.error(err);
        });
};

Requiring cute-stack before Glue is called results in an error. However, placing the require after Glue has returned a server instance, works fine.

[jamesdixon]

FYI: Glue is a Hapi module that allows for composition of the server via an external configuration file: https://github.com/hapijs/glue

[davidmarkclements]

yeah - so... not sure there's much to be done about this, other than identifying the case and outputting a more helpful message of what the issue might be

[jamesdixon]

Would it have anything to do with the fact that modules aren't loaded yet before Glue returns the server? Sorry, this is a little beyond me, so just speculating :)

[timmeade]

Same issue here. I had to move the require until after express starts. Works then, otherwise I get this error.

[neves]

Same here, it just works after another require.