> On May 10, 2016, at 3:52 PM, Quincey Morris > <quinceymor...@rivergatesoftware.com> wrote: > > On May 10, 2016, at 13:38 , Carl Hoefs <newsli...@autonomy.caltech.edu > <mailto:newsli...@autonomy.caltech.edu>> wrote: >> >> At last, it blew again! > > Well, here’s the exception message: > >> An -observeValueForKeyPath:ofObject:change:context: message was received but >> not handled. >> Key path: operations >> Observed object: <NSOperationQueue: 0x14eae190>{name = 'Upload Queue'} >> Change: { >> kind = 1; >> } >> Context: 0x0 > > > So, some object has established itself as an observer of changes to the > “operations” property of the NSOperationQueue named “Upload Queue”, but has > failed to act on the observed change. Since the message says “received but > not handled”, the likelihood is that the observer object *has* a method named > 'observeValueForKeyPath:ofObject:change:context:’ (or one of its superclasses > does), and is invoking the ‘super’ method to pass the change upwards to an > ancestor class, but nothing actually handles it. > > The most likely cause is that the observer registered itself using > ‘addObserver:forKeyPath:options:context:’ specifying a nil context, but is > checking for a different context in > 'observeValueForKeyPath:ofObject:change:context:’. > > It’s also possible that the exception message means something more obscure, > in which case the cause may be more complicated, but you should search your > code for ‘addObserver’ and ‘observeValueForKeyPath’, and make sure that the > context is set and checked consistently. (Your code should *never* use a nil > context explicitly.) > Yes, yes, and yes! I'm using a nil context. I'm not sure how context is to be used here... Is this an arbitrary value that I check in -observeValueForKeyPath? -Carl
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