iOS 11 Crashes - Invalid State Transformation while Evaluating Conditions

[biocross]

Overdrive: 0.3
Package manager (SPM, Carthage, CocoaPods, Manual): CocoaPods
Xcode: 9.0 beta 6
Platform: iOS

The dependency system seems to be failing in iOS 11. I have tried this with Xcode 9 betas 6 & 7 (latest right now). Quite a few tests are failing, especially an assertion failure TaskConditionTests, which seems to be the most severe, which actually is affecting our production users on iOS betas with crashes.

[saidsikira]

Hi, Thanks for reporting this, I'll take a look later today. Have a nice day, Said

…

On 22 Aug 2017, 12:41 +0200, Siddharth Gupta ***@***.***>, wrote: Overdrive: 0.3 Package manager (SPM, Carthage, CocoaPods, Manual): CocoaPods Xcode: 9.0 beta 6 Platform: iOS The dependency system seems to be failing in iOS 11. I have tried this with Xcode 9 betas 6 & 7 (latest right now). Quite a few tests are failing, especially an assertion failure TaskConditionTests, which seems to be the most severe, which actually is affecting our production users on iOS betas with crashes. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub, or mute the thread.

[biocross]

I have gotten around this temporarily by replacing
assert(internalState.canTransition(to: newState, isCancelled: isCancelled), "Invalid state transformation from \(internalState) to \(newState)") internalState = newState

with

if(internalState.canTransition(to: newState, isCancelled: isCancelled)){ internalState = newState }

in TaskBase.swift (state variable setter)

For the time being, this fixes the crashes, as well passes the tests on the iOS 11 simulator. This is basically preventing invalid state transformations.

[biocross]

Hey, could you get the time to look at this?

[saidsikira]

I'll have access to my laptop tomorrow evening and I'll be able to debug and hopefully fix it then.

…

On 25 Aug 2017, 08:35 +0200, Siddharth Gupta ***@***.***>, wrote: Hey, could you get the time to look at this? — You are receiving this because you commented. Reply to this email directly, view it on GitHub, or mute the thread.

[saidsikira]

@biocross you say that you've ran unit tests on Xcode 9 beta, does that mean that you converted project to Swift 4? I'm currently running tests on Xcode 9 and every test is passing. If you're interested in that you can look into swift4 branch of the repo.

However, you have a problem in production with iOS 11. Could you supply me with a piece of code that can showcase problems you're having? Then, I'll be able to investigate more.

[biocross]

I didn't convert the code to Swift 4. Basically, due to evaluateConditions being called twice on tasks, the task is moving to the ready state twice, leading to an assertion failure in TaskBase.swift, and crashing in debug. In release mode, even if the assertion is disabled, invalid state transformation end up crashing my tasks.

[biocross]

Hey one thing, tests pass for me in Xcode 9, if I target my mac. Did you target an iOS 11 simulator to run the tests?

[biocross]

Hey, any update?

[saidsikira]

I have confirmed that there is a different behavior between iOS 10 and iOS 11, still trying to figure out why. I should have a fix by the end of the day.

[saidsikira]

Looks like the behavior of several KVO methods is slightly changed in iOS 11. For now, you can try out fix in the conditions-fix branch.

It's mostly a hack until I rewrite some of the internal stuff, but it should work.

Let me know if it works for you.

[biocross]

Alright. Thanks a lot! Seems to work, considering the tests pass.