Crashes related to an invalid popover

[buddybuild]

Buddybuild detected a crash
Exception Class: NSInvalidArgumentException

-[__NSCFString dismissPopoverAnimated:userInitiated:]: unrecognized selector sent to instance 0x1c40dcbd0

View Full Crash Details

[nbrooke]

There are a set of crashes of this general form across the last couple builds. This one is from the previous release that added the AR functionality, but there are similar ones from the current release, just with a slightly less obvious crash, and the release from last year pre-AR.

Some touch event gets sent to something that seems to be expected to be a popover controller, but isn't, and throws an unrecognized selector exception (as in this one). There are also some that look very similar in terms of callstack, but just die on objc_msg_send (so aren't as obviously popover-involved). #583 could possibly be another symptom of this, it's a crash also in something popover related, that doesn't seem to make any sense (it's a type of popover that AFAICT we never present, which means some sort of invalid object is likely).

Best working theory right now: there is some unusual situation in which one of the popover controllers in the app (the menu dropdowns or the node information) can get over-released, and gets freed while there are still active references to it, and then bad things happen when it is accessed, including this crash, and maybe stomping memory and causing less obviously related crashes.

Of note: the WEPopover library that we use to allow popovers on the iPhone (they were only supported on iPad when originally written) is not the latest version, and indeed is old enough that it does not use ARC (!). So it's a strong candidate for the culprit here. A good first stab at this would be to replace that with something more modern, either an updated version of that, or maybe just ditching that (I think that popovers are better supported by UIKit on iPhones now then they were at the time this was originally written).

cc: @apike