`set_size` can cause seg fault when value too large on macOS

[mikebenfield]

Sometimes I get a panic; sometimes a seg fault.

$ cat src/main.rs

extern crate sdl2;

fn main() {
    let sdl = sdl2::init().unwrap();
    let vid = sdl.video().unwrap();
    let mut win = vid.window(&"", 128, 128)
        .build().unwrap();
    win.set_size(i32::max_value() as u32, 100);
}
$ cargo run
2017-09-01 17:57:12.947 sdl2_crash[11065:5671348] *** Assertion failure in -[_NSCGSWindow setFrame:], /Library/Caches/com.apple.xbs/Sources/AppKit/AppKit-1504.82.104/CGS.subproj/NSCGSWindow.m:663
thread 'main' panicked at 'called `Option::unwrap()` on a `None` value', src/libcore/option.rs:335:20
note: Run with `RUST_BACKTRACE=1` for a backtrace.
fatal runtime error: failed to initiate panic, error 5
Abort trap: 6
$ cargo run
    Finished dev [unoptimized + debuginfo] target(s) in 0.0 secs
     Running `target/debug/sdl2_crash`
2017-09-01 17:57:30.372 sdl2_crash[11080:5671827] *** Assertion failure in -[_NSCGSWindow setFrame:], /Library/Caches/com.apple.xbs/Sources/AppKit/AppKit-1504.82.104/CGS.subproj/NSCGSWindow.m:663
Segmentation fault: 11

Mac OS 10.12.4.

[Cobrand]

win.set_size(i32::max_value() as u32, 100);

How would you expect the library to behave?

[Cobrand]

Unable to reproduce; no crash on Linux.

[mikebenfield]

How would you expect the library to behave?

Panic or return an error? Safe code in Rust isn't supposed to segfault.

[Cobrand]

The segfault is coming from your OS, not from SDL2. Can you sho me the full backtrace? I'd like to know where that panic comes from.

There is not much I can do aside from "assert"-ing that the new size is below a certain value that would be deemed safe, but again you shouldn't have to set your window to such a size in the first place; what would be a "too big" value for SDL2 to panic?

[mikebenfield]

I've been unable to reproduce the panic; only a segfault, and I don't think I can get a backtrace from a segfault.

There is not much I can do aside from "assert"-ing that the new size is below a certain value that would be deemed safe

Yes, this is what I am asking for.

again you shouldn't have to set your window to such a size in the first place

Of course not; if my program did that, it would be a bug... which I would like to be easy to fix, because I got a panic or an error return, instead of a segfault.

[Cobrand]

Well, if you tell me what is the maximum value your OS accepts, we can make an assert of the like for sure.

[ebarnard]

From https://developer.apple.com/documentation/appkit/nswindow/1419753-setframe?language=objc

Max size (Window::set_size, Window::set_maximum_size, Window::set_minimum_size): 10000x10000
Max position (Window::set_position): (±16000, ±16000)

[mnmaita]

What would be the best way to check the current platform within the library?

[Cobrand]

Either at compile time with the "cfg" attributes, or at runtime using https://docs.rs/sdl2/0.32.2/sdl2/fn.get_platform.html