println seems to prevent proper App exit

[Z35hLy48k]

Issue Encountered:

Trying to exit the game with exit.send(AppExit).
The window closes but the program's process is still running and terminal window hangs.

After removing all println() from the code, the App exits properly.

Code that might help to reproduce :

fn quit(
    keys: Res<Input<KeyCode>>,
    mut exit: EventWriter<AppExit>
) {
    if keys.pressed(KeyCode::LControl) && keys.pressed(KeyCode::C) {
        println!("Exiting...");
        exit.send(AppExit);
    }
}

Bevy 0.5.0
OS: Linux

[DJMcNab]

Are you able to reproduce on main? I can't point to any specific reason this would fail, and indeed this seems really strange.

Maybe something is holding a lock on stdout? Do any of the prints happen?

[bjorn3]

For me

diff --git a/examples/2d/contributors.rs b/examples/2d/contributors.rs
index cefce614..54cb40a9 100644
--- a/examples/2d/contributors.rs
+++ b/examples/2d/contributors.rs
@@ -1,4 +1,4 @@
-use bevy::{prelude::*, utils::HashSet};
+use bevy::{prelude::*, utils::HashSet, app::AppExit};
 use rand::{prelude::SliceRandom, Rng};
 use std::{
     env::VarError,
@@ -15,9 +15,20 @@ fn main() {
         .add_system(move_system)
         .add_system(collision_system)
         .add_system(select_system)
+        .add_system(quit)
         .run();
 }
 
+fn quit(
+    keys: Res<Input<KeyCode>>,
+    mut exit: EventWriter<AppExit>
+) {
+    if keys.pressed(KeyCode::LControl) && keys.pressed(KeyCode::C) {
+        println!("Exiting...");
+        exit.send(AppExit);
+    }
+}
+
 // Store contributors in a collection that preserves the uniqueness
 type Contributors = HashSet<String>;

works just fine as of add1818. What did you do to reproduce it @DJMcNab?

[Z35hLy48k]

I couldn't reproduce on another pc !

[Z35hLy48k]

Do any of the prints happen?

Yes they do happen!

This might be a minor issue that I randomly encountered after all !

[alice-i-cecile]

I'm going to close this out then: if anyone else encounters this or can reproduce we'll reopen it :)

[bzar]

Hi, encountering this as well on Bevy 0.6. Removing printlns makes my pong exit cleanly, reintroducing them keeps the process running after exit.

EDIT: Actually, now encountering it even without the printlns. Ignore this report.

[jakoschiko]

The window closes but the program's process is still running and terminal window hangs.

I have the same problem without any println. I'm using Arch Linux and bevy 0.8. Is there an issue that addresses this problem?

[BorisBoutillier]

@jakoschiko is it similar to #5524 ?