From b6da40cfe6d3686ef01b8708dc8e6f5c66229bdc Mon Sep 17 00:00:00 2001
From: Chia-Hsiang Cheng <88014292+garychia@users.noreply.github.com>
Date: Wed, 3 Jan 2024 23:32:57 +0800
Subject: [PATCH] Print a warning for un-applied commands being dropped from a
 CommandQueue (#11146)

# Objective

- Fixes #11125
## Solution

Add a warning for un-applied commands to the `drop` function.
---
 crates/bevy_ecs/src/system/commands/command_queue.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/crates/bevy_ecs/src/system/commands/command_queue.rs b/crates/bevy_ecs/src/system/commands/command_queue.rs
index f68031c3d39b0..5130089cc8fd2 100644
--- a/crates/bevy_ecs/src/system/commands/command_queue.rs
+++ b/crates/bevy_ecs/src/system/commands/command_queue.rs
@@ -1,6 +1,7 @@
 use std::mem::MaybeUninit;
 
 use bevy_ptr::{OwningPtr, Unaligned};
+use bevy_utils::tracing::warn;
 
 use super::Command;
 use crate::world::World;
@@ -161,6 +162,9 @@ impl CommandQueue {
 
 impl Drop for CommandQueue {
     fn drop(&mut self) {
+        if !self.bytes.is_empty() {
+            warn!("CommandQueue has un-applied commands being dropped.");
+        }
         self.apply_or_drop_queued(None);
     }
 }