Crash on MD5 section possible conflict

[blaineam]

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Issue Description

I am currently using my switfyhash md5 hashing library and after a random number from 10-4000 photos being fetched by a ImagePrefetcher it crashes on the stringproxy.md5.getter see attached screenshot. I cannot figure out what if any possible conflict there is and am still investigated. I was just wondering if you might have an idea as to what could be going wrong. Thank You. I am hashing md5 within the completion handler if that helps at all.

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[onevcat]

I noticed that you are fetching a lot of images and it might be a problem of the stack. The completion stack is too large and it might be a stack overflow.

Could you confirm that this issue only happens when you have a large number of images?

If so, a possible quick workaround is breaking down your images into smaller set and download it with multiple prefetchers.

[blaineam]

I removed the whole prefetched code out from a dispatch in background task and it is running a lot better and hasn't crashed yet however I'm noticing what appears to be socket errors in writing data. they aren't crashing the app but I am wondering If I'm running through everything too quickly? I might have to break the images into smaller sets as the though did cross my mind thank you. and yeah there is a lot of images being fetched. Thanks for the fast reply.

[cl3m]

@onevcat I had the same problem. It seems the recursion is too deep when prefetching thousand of image.
The easiest solution was to add an DispatchQueue.main.async in reportCompletionOrStartNext.

[onevcat]

@cl3m Good catch on it. I will try it soon. Thanks!

[onevcat]

The prefetcher stack overflow issue should be fixed in 4.4.1. (preparing a release now.)