Re: [RFC 4/5] rust: sync: impl Debug for {Unique,}Arc

[Gary Guo]

On Wed,  1 Feb 2023 15:22:43 -0800
Boqun Feng <boqun.feng@xxxxxxxxx> wrote:

> This allows printing macros to print the data and the refcount nubmer
> of these struct for debugging purposes.
> 
> Signed-off-by: Boqun Feng <boqun.feng@xxxxxxxxx>
> ---
>  rust/kernel/sync/arc.rs | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/rust/kernel/sync/arc.rs b/rust/kernel/sync/arc.rs
> index 4d8de20c996f..f143d8305c36 100644
> --- a/rust/kernel/sync/arc.rs
> +++ b/rust/kernel/sync/arc.rs
> @@ -474,6 +474,7 @@ impl<T: ?Sized> Deref for ArcBorrow<'_, T> {
>  ///
>  /// # test().unwrap();
>  /// ```
> +#[derive(Debug)]

I don't think this should be a `#[derive(Debug)]`. For `UniqueArc` the
refcount field in `Arc` is useless, and we should just delegate the
`Debug` impl to that of deref, just like `Display` does.

Best,
Gary