Panic with ControlFlow::Wait when computer goes to sleep on Linux/X11

[jfrimmel]

Hello,

I encountered a panic within winit when putting my closing and re-opening the lid on my laptop (i.e. when sleep mode is entered) while executing the winit (version 0.24+) application:

thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Os { code: 4, kind: Interrupted, message: "Interrupted system call" }', /home/jfrimmel/.cargo/registry/src/github.com-1ecc6299db9ec823/winit-0.25.0/src/platform_impl/linux/x11/mod.rs:360:54
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

The platform is Linux with only the x11 feature enabled. I haven't checked other platforms.

Reproduction

$ cargo new winit-sleep-linux
$ cd winit-sleep-linux
$ echo 'winit = { version = "0.25", default-features = false, features=["x11"]}' >> Cargo.toml
$ nano src/main.rs # insert code below
$ cargo run # close the lid/enter sleep otherwise; wait a short time; open the lid/leave sleep mode

The content of src/main.rs is very simle and reduced, it does not even contain a window:

fn main() {
    let event_loop = winit::event_loop::EventLoop::new();
    event_loop.run(|_, _, control_flow| *control_flow = winit::event_loop::ControlFlow::Wait);
}

Backtrace

thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Os { code: 4, kind: Interrupted, message: "Interrupted system call" }', /home/jfrimmel/.cargo/registry/src/github.com-1ecc6299db9ec823/winit-0.25.0/src/platform_impl/linux/x11/mod.rs:360:54
stack backtrace:
   0: rust_begin_unwind
             at /rustc/9bc8c42bb2f19e745a63f3445f1ac248fb015e53/library/std/src/panicking.rs:493:5
   1: core::panicking::panic_fmt
             at /rustc/9bc8c42bb2f19e745a63f3445f1ac248fb015e53/library/core/src/panicking.rs:92:14
   2: core::option::expect_none_failed
             at /rustc/9bc8c42bb2f19e745a63f3445f1ac248fb015e53/library/core/src/option.rs:1329:5
   3: core::result::Result<T,E>::unwrap
             at /home/jfrimmel/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/result.rs:1037:23
   4: winit::platform_impl::platform::x11::EventLoop<T>::run_return
             at /home/jfrimmel/.cargo/registry/src/github.com-1ecc6299db9ec823/winit-0.25.0/src/platform_impl/linux/x11/mod.rs:360:17
   5: winit::platform_impl::platform::x11::EventLoop<T>::run
             at /home/jfrimmel/.cargo/registry/src/github.com-1ecc6299db9ec823/winit-0.25.0/src/platform_impl/linux/x11/mod.rs:385:9
   6: winit::platform_impl::platform::EventLoop<T>::run
             at /home/jfrimmel/.cargo/registry/src/github.com-1ecc6299db9ec823/winit-0.25.0/src/platform_impl/linux/mod.rs:662:56
   7: winit::event_loop::EventLoop<T>::run
             at /home/jfrimmel/.cargo/registry/src/github.com-1ecc6299db9ec823/winit-0.25.0/src/event_loop.rs:154:9
   8: winit_sleep_linux::main
             at ./src/main.rs:3:5
   9: core::ops::function::FnOnce::call_once
             at /home/jfrimmel/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ops/function.rs:227:5
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

[jfrimmel]

I've created a patch (#1952), that prevents the panic in the example above. One can test this out by adding the following two lines to the Cargo.toml from above:

[patch.crates-io]
winit = { git = "https://github.com/jfrimmel/winit", branch = "x11-interrupt" }