Avoid leaking submitted command encoders (#5141)

* Avoid leaking submitted command encoders

* changelog

CHANGELOG.md

@@ -154,6 +154,7 @@ By @atlv24 in [#5383](https://github.com/gfx-rs/wgpu/pull/5383)
 - Ensure render pipelines have at least 1 target. By @ErichDonGubler in [#5715](https://github.com/gfx-rs/wgpu/pull/5715)
 - `wgpu::ComputePass` now internally takes ownership of `QuerySet` for both `wgpu::ComputePassTimestampWrites` as well as timestamp writes and statistics query, fixing crashes when destroying `QuerySet` before ending the pass. By @wumpf in [#5671](https://github.com/gfx-rs/wgpu/pull/5671)
 - Validate resources passed during compute pass recording for mismatching device. By @wumpf in [#5779](https://github.com/gfx-rs/wgpu/pull/5779)
+- Fix a `CommandBuffer` leak. By @cwfitzgerald and @nical in [#5141](https://github.com/gfx-rs/wgpu/pull/5141)
 
 #### DX12
 

wgpu/src/backend/wgpu_core.rs

@@ -2326,10 +2326,17 @@ impl crate::Context for ContextWgpuCore {
             .map(|(i, _)| i)
             .collect::<SmallVec<[_; 4]>>();
 
-        match wgc::gfx_select!(*queue => self.0.queue_submit(*queue, &temp_command_buffers)) {
+        let index = match wgc::gfx_select!(*queue => self.0.queue_submit(*queue, &temp_command_buffers))
+        {
             Ok(index) => index,
             Err(err) => self.handle_error_fatal(err, "Queue::submit"),
+        };
+
+        for cmdbuf in &temp_command_buffers {
+            wgc::gfx_select!(*queue => self.0.command_buffer_drop(*cmdbuf));
         }
+
+        index
     }
 
     fn queue_get_timestamp_period(