Silent crash on node 6

[scottnonnenberg]

Thanks for this package. So useful! :0)

I downloaded it and tried it on my blog today, and it was giving me just four lines of output. Confused, I started looking at the code, and realized that it finished in the middle of enqueuing its first set of links. With a new try/catch in HtmlChecker/enqueueLink I found that the process was indeed silently crashing:

TypeError: source.hasOwnProperty is not a function
    at cloneObject (lib/internal/linkObj.js:239:14)
    at cloneObject (lib/internal/linkObj.js:245:18)
    at cloneObject (lib/internal/linkObj.js:245:18)
    at Function.linkObj.resolve (lib/internal/linkObj.js:168:64)
    at enqueueLink (lib/public/HtmlChecker.js:158:10)
    at lib/public/HtmlChecker.js:110:5
    at process._tickCallback (internal/process/next_tick.js:103:7)

On node 6.1.0 it throws this error, and on node 4.4.3 it works properly. Seems that there are two bugs here - one about the hasOwnProperty issue, and the other about silently crashing!

[scottnonnenberg]

Figured it out - it's because the value returned by querystring.parse() is now created via Object.create(null) instead of inheriting from object: https://github.com/nodejs/node/wiki/Breaking-changes-between-v5-and-v6#querystring

Fixing this will also require changes in the urlobj repo: https://github.com/stevenvachon/urlobj

Researching now, may have a couple pull requests ready soon...

[scottnonnenberg]

I was able to fix the silent error thing by installing bluebird as the replacement for global.Promise - it provides a key method: onPossiblyUnhandledRejection(). In bin/blc:

var Bluebird = require('bluebird');
global.Promise = Bluebird;

Bluebird.onPossiblyUnhandledRejection(function(error){
  throw error;
});

Worth thinking about. Sadly, this method is not available in the standard promise implementation.

Either that, or get really rigorous always returning rejected promises up the stack. Lines 97-118 in HtmlChecker.js are a good example: a call().then() with no catch and no return. Gotta either return the promise up the stack or handle the error right there. Otherwise errors will be swallowed.

Here's something I wrote about promises: https://blog.scottnonnenberg.com/the-trouble-with-promises/