Crash on zoom

[calkinssean]

Hi, if I zoom in too fast and far my app crashes. The error I am getting is fatal error: stride must not be zero. I noticed on your demo apps there seems to be a max zoom which eliminates this crash. I am wondering how I can implement this.

[liuxuan30]

please paste the stack trace when crashing. It's better if we know how to reproduce with ChartsDemo

[danielgindi]

I'm assuming it's because of the move to Swift 2.2.
Apple failed to mention that when they automatically convert a for loop to a Stride, the result is far from the same. Because Stride insists on throwing exceptions when it has nothing to loop over, instead of just doing nothing.

@calkinssean If you can point us to which line of code produces the exception - it could be easily fixed.

[danielgindi]

Well the stride I know crashes- and you can see it in Stride's source
code... I've sent a PR to Apple

[liuxuan30]

I see that. the stride cannot be 0, but old c loop will has infinite loop.

[danielgindi]

Why an infinite loop?

for (var i = 0; i < 0; i +=0) {
  // This will not be called, as "i < 0" is not satisfied
}

[liuxuan30]

oops, my bad. I mean <= when I said infinite loop

[danielgindi]

Oops - it's actually my bad, as I didn't see that it's a case of through which is <=.

I'll have to look at the code again to make sure that the extra axis line is not missing in cases where last-first is an exact multiplication of interval.

I'll also need to make tests for Swift Stride to make sure that there are no infinite loop cases.

[danielgindi]

After running some tests I'm writing for the PR - it looks like the Swift precondition is meant for checking the interval, not the to or through. Will almost definitely cause an infinite loop... Unless the test is less than

[liuxuan30]

We evolved from crash/not responding after a few minutes to crash directly :)