Longer stack trace on unhandled error events

[olalonde]

• Version: v5.5.0
• Platform: Darwin mbpro 15.0.0 Darwin Kernel Version 15.0.0: Wed Aug 26 16:57:32 PDT 2015; root:xnu-3247.1.106~1/RELEASE_X86_64 x86_64
• Subsystem: events.js

I am getting the following error in my code:

events.js:154
      throw er; // Unhandled 'error' event
      ^

Error: ENOENT: no such file or directory, open '/assets/screencast-preview.png'
    at Error (native)

Unfortunately, the stack trace doesn't tell me where the error was produced in the code. I was wondering if there was any way to get a longer stack trace on this or if it isn't possible due to the way events are implemented in Node.js.

[jasnell]

Unfortunately I don't believe it is currently possible to get a longer stack trace on this particular set of errors due to the way the callback is disconnected from it's original context. It's definitely something that should be investigated further tho. /cc @bnoordhuis

[bnoordhuis]

It's not possible to collect long stack traces efficiently (and that's why node core doesn't do it) but if efficiency is of less concern, try longjohn.

[benjamingr]

Yeah this is not really something that should belong in core - but userland libraries like longjohn solve it in userland and promise libraries also do it.

[olalonde]

Ok, I see, I'm not looking for a crazy long stack trace though, just one or two calls before "at Error (native)". Node core does usually collect and display stack traces longer than this one though it doesn't seem to do so in this particular case (unhandled error event). I understand it might not be possible to do it efficiently though.

[cjihrig]

Closing as a won't fix in core. As previously noted, look into longjohn.