Handling divide by zero

[tera]

I bet the ultimate reason is CGFloat being a separate type and all the sleight of hand needed for it to co-play with doubles.

func test(angle: Angle) {
    let a: CGFloat = 0
    CGPoint(x: a + cos(angle.radians), y: a + cos(angle.radians))
    // Ambiguous use of 'cos'
}

Change the above a little bit one way or another – and it compiles fine.

[Hacksaw]

Filed: FB21792467

[Hacksaw]

I feel like there’s a lot of little gotchas waiting for someone to find the right combo of stuff, what with all the various wrappers, call backs to Obj-C, funky protocol shenanigans…

That it works as well as it does says something positive about the people involved.

[matthewruzzi]

Could you post the reports on Open Feedback Assistant?

GitHub - feedback-assistant/reports: Open collection of Apple Feedback Assistant...

[Slava_Pestov]

@Hacksaw

Trying to produce one, but now compilation is crashing.

Here’s the code that is freaking it out:

import SwiftUI

struct TestView: View {
  @State var angle: Angle = Angle(radians: Double.pi/1.5)
  let size = CGSize(width: 800, height: 600)
  var body: some View {
    Path { path in
      path.move(to: CGPoint(x: size.width/cos(angle.radians) , y: size.height/cos(angle.radians)))
      path.addLine(to: CGPoint(x: 100, y: 100))
    }.stroke(Color.red)
  }
}

#Preview {
  TestView()
}

For what it's worth, I can reproduce a crash with 6.2, but it no longer crashes for me with the latest 6.3 snapshot, or a compiler I built myself from main.

Thank you for your contribution to the test suite ;-) Sema: Add regression test for fixed crasher by slavapestov · Pull Request #86864 · swiftlang/swift · GitHub

[Hacksaw]

File type .swift not supported? Really?

[Hacksaw]

#761

[Hacksaw]

The saga gets weirder:

In trying to narrow down the problem, I decided to remove a style configuration.

In the example I sent to Apple, there is this code:

//Cosecant Line indicator
      Path { path in
        path.move(to: pt(qdt.qx * -20, 0))
        // DIV BY ZERO
        path.addLine(to: pt(qdt.qx * -20, qdt.qy * sH/cos(angle.radians)))
      }
      .stroke(Color.orange,  style: dashStyle)
      .transformEffect(.init(1, 0, 0, -1, ctr.x, ctr.y))

I removed the “style: dashStyle” part of the stroke call, and suddenly it works.

Or if I put that back, and change the starting angle to be something other than tau*3.0/4.0 or tau/4.0, no crash.

See FB21792467: Kill The Window Server with MATH · Issue #761 · feedback-assistant/reports · GitHub for the full example.

[ksluder (Kyle Sluder)]

Thanks for the additional investigation. I’ve made sure the WindowServer team is aware of your report.