Fix symbolication in Yosemite and Xcode6

[jerrymarino]

While this fixes the dead lock bug Yosemite, I still think this feature could be improved:

• During a focused run, for each additional node before the focused node, there's a call to atos to symbolicate the callers address. It should instead be performed once with all the potential caller addresses of it/before/context nodes in the focused file. This would be a huge improvement (Kiwi test suite hangs indefinitely in KWSymbolicator while waiting for /usr/bin/atos #596).

"atos in 10.0 with a process id no longer works for the simulator so use the
executable path instead.

This patch introduces KWBackgroundTask to remove use of the dangerous
-[NSTask waitUntilExit]; and encapsulate use of NSTask.

• breakout callsite creation for symbolicated addresses from KWExample by adding
  a factory for KWCallSite."

[ecaselles]

👍 I would love to see this fix merged in, since it is a pitty not being able to run the tests from Xcode 🙏

[sharplet]

This import doesn't appear to be used anywhere in this file.

[sharplet]

Thanks @jerrymarino, I've tested this out on my machine and it appears to work just fine! 👍

I'm a little bit nervous about this code:

• Will this still work fine on other versions of OS X?
• Anything involving dyld.h is currently, unfortunately, beyond my understanding.

So to the end of making this as clear as possible for future maintainers, what do you think about these suggestions?

• Move KWBackgroundTask into its own source file. This should hopefully ensure that all of the async code involving CFRunLoop is fully encapsulated.
• Document the actual symbolication stuff in some way. I'm thinking developer-focused documentation here, whether it's comments in the implementation providing a bit more context, or maybe a separate file, or something. I think even just having some more method/function doc comments could be really valuable here, and even potentially splitting out some smaller methods/functions if it makes sense.
• Or any other ideas you have! 😁

Ultimately I'm happy to merge this pretty soon, but if there's anything we can do to improve the overall clarity of this beforehand I think that would be a win for everybody!

[sharplet]

Thanks again @jerrymarino! I decided to go ahead and extract KWBackgroundTask into its own file. Great to have the tests running again! 👏

[jerrymarino]

Hey @sharplet glad I could help out on this one.

I tested it out on both 10.9 and 10.10 and it worked great. I believe atos supported the updated arguments in 10.8 too. I hope atos functionality is stabilized in future releases. If it stops working again the error handling we've got now should make it obvious 🍻

It'd be helpful to have developer documentation for this. Inline comments could be sufficient and potentially add a page/section in the wiki for higher level design documentation. Do you think it is appropriate to put design docs in the wiki some where?

I'll can submit a follow up soon 😄

[sharplet]

@jerrymarino I think I'd prefer to keep to user-facing docs in the wiki. So something in the source code should be most appropriate for developer documentation! I'd be happy for you to create a new Documentation/ directory for the higher-level stuff.

[lyahdav]

I just ran into this issue on Kiwi 2.3.1 (since it's the latest Kiwi version on cocoapods). Will there be an official Kiwi release with this fix anytime soon so we don't have to use master?

[sharplet]

@lyahdav Yep, just pushed 2.4.0! https://github.com/kiwi-bdd/Kiwi/releases/tag/v2.4.0

[ecaselles]

@sharplet 👏🎉🎊🎆✨💥🎋🎏

[lyahdav]

I'm still getting this deadlock. OS X 10.10.5, Xcode 7.0, iOS 9.0, Kiwi 2.4.0.