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iphonecocoacore-datamapping-modelcore-data-migration

Core Data: endless loop while auto-migrating between two data models

I have my old data model, my new model (same but with two more text fields in one entity) and a mapping model (just the default generated one).

When I do automatic migration, I get a crash and a stacktrace that looks like it's entered an endless loop, 62851 stack frames, mostly _PF_Handler_Public_GetProperty and descriptions on NSManagedObject, terminated by a malloc error, which I assume is the endless loop running out of memory on my device.

stack trace

Do you have any idea what can lead to such an endless loop? I have no idea where to start debugging this.

Cheers

Nik

Solution

  • Start under debugger and then click pause. Then try to step thru and try to find the reason for looping. Could it be that the same data is read again and again without stepping forward? If this doesn't help, comment out some code and see if it reproduces. Keep doing so and you may find your faulty block. This post might be helpful How do I debug my program when it hangs?.