Fix crash in simple_window example

[ids1024]

We need to handle or ignore events from wl_shm and wl_surface, since the server does in fact produce events for those.

[i509VCB]

Wait why are we ignoring WlShm?

I'd think that knowing what formats are supported would be effectively mandatory?

[ids1024]

All renderers should support argb8888 and xrgb8888 but any other formats are optional and may not be supported by the particular renderer in use.

https://wayland.app/protocols/wayland

So I think it's perfectly valid for the example to simply assume wl_shm::Format::Argb8888 is available.

[softmoth]

I'm still seeing a crash here, even with adding ignore to these two lines. If I revert commit be86c69 then the crash goes away and I get a successful window.

% RUST_BACKTRACE=1 cargo run
   Compiling wl-alttab v0.1.0 (/home/trs/g/wl-alttab)
    Finished dev [unoptimized + debuginfo] target(s) in 0.27s
     Running `target/debug/wl-alttab`
Starting the example window app, press <ESC> to quit.
thread 'main' panicked at 'internal error: entered unreachable code', src/main.rs:121:1
stack backtrace:
   0: rust_begin_unwind
             at /rustc/371994e0d8380600ddda78ca1be937c7fb179b49/library/std/src/panicking.rs:593:5
   1: core::panicking::panic_fmt
             at /rustc/371994e0d8380600ddda78ca1be937c7fb179b49/library/core/src/panicking.rs:67:14
   2: core::panicking::panic
             at /rustc/371994e0d8380600ddda78ca1be937c7fb179b49/library/core/src/panicking.rs:117:5
   3: <wl_alttab::State as wayland_client::event_queue::Dispatch<wayland_client::protocol::wl_buffer::WlBuffer,()>>::event
             at /home/trs/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wayland-client-0.30.2/src/event_queue.rs:843:17
   4: wayland_client::event_queue::queue_callback
             at /home/trs/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wayland-client-0.30.2/src/event_queue.rs:651:5
   5: wayland_client::event_queue::EventQueue<State>::dispatching_impl
             at /home/trs/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wayland-client-0.30.2/src/event_queue.rs:473:13
   6: wayland_client::event_queue::EventQueue<State>::dispatch_pending
             at /home/trs/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wayland-client-0.30.2/src/event_queue.rs:376:9
   7: wayland_client::event_queue::EventQueue<State>::blocking_dispatch
             at /home/trs/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wayland-client-0.30.2/src/event_queue.rs:404:9
   8: wl_alttab::main
             at ./src/main.rs:37:9
   9: core::ops::function::FnOnce::call_once
             at /rustc/371994e0d8380600ddda78ca1be937c7fb179b49/library/core/src/ops/function.rs:250:5
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

[softmoth]

Ah, I see the problem. It is WlShm and WlBuffer that need to be ignored, not WlSurface. I.e., this does not crash:

// Ignore events from these object types in this example.
delegate_noop!(State: wl_compositor::WlCompositor);
delegate_noop!(State: wl_surface::WlSurface);
delegate_noop!(State: ignore wl_shm::WlShm);
delegate_noop!(State: wl_shm_pool::WlShmPool);
delegate_noop!(State: ignore wl_buffer::WlBuffer);

I'm using a freshly updated +nightly, and my Cargo.toml says:

[dependencies]
wayland-client = { version = "*" }
wayland-protocols = { version = "*", features = ["client"] }
tempfile = "*"

I don't know if different environments cause different events. I'm on Arch Linux, running sway with the nvidia 535.86.05 driver.

[softmoth]

By the way, it would be simplest to ignore all of these, since that is what the code did before be86c69 and was probably the intention of that commit.

[codecov]

Codecov Report

Patch and project coverage have no change.

Comparison is base (799c772) 73.11% compared to head (947455f) 73.12%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #644   +/-   ##
=======================================
  Coverage   73.11%   73.12%           
=======================================
  Files          47       47           
  Lines        7693     7692    -1     
=======================================
  Hits         5625     5625           
+ Misses       2068     2067    -1     

Flag	Coverage Δ
main	58.61% <ø> (+<0.01%)	⬆️
test--	78.10% <ø> (ø)
test--server_system	61.30% <ø> (ø)
test-client_system-	69.13% <ø> (ø)
test-client_system-server_system	51.32% <ø> (ø)

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see 1 file with indirect coverage changes

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[i509VCB]

@elinorbgr comments?