[Libguestfs] [nbdkit PATCH] rust: prevent dead_code warning

[Richard W.M. Jones]

On Fri, Oct 14, 2022 at 10:42:30PM +0200, Thomas Weißschuh wrote:
> rustc 1.64.0 generates warnings for the mocked Server.
> This leads to a failure of test.sh.
> 
> ```
> warning: associated function `expect` is never used
>   --> tests/common/mod.rs:49:1
>    |
> 49 | / mock!{
> 50 | |     pub Server {}
> 51 | |     impl Server for Server {
> 52 | |         fn cache(&self, count: u32, offset: u64) -> Result<()>;
> ...  |
> 86 | |     }
> 87 | | }
>    | |_^
>    |
>    = note: `#[warn(dead_code)]` on by default
> ```
> ---
> 
> Note: This also affects the maintenance branches.
> 
>  plugins/rust/tests/common/mod.rs | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/plugins/rust/tests/common/mod.rs b/plugins/rust/tests/common/mod.rs
> index 61c30464..de26c89f 100644
> --- a/plugins/rust/tests/common/mod.rs
> +++ b/plugins/rust/tests/common/mod.rs
> @@ -48,6 +48,7 @@ lazy_static! {
>  
>  mock!{
>      pub Server {}
> +    #[allow(dead_code)]
>      impl Server for Server {
>          fn cache(&self, count: u32, offset: u64) -> Result<()>;
>          fn can_cache(&self) -> Result<CacheFlags>;
> 
> base-commit: 20c2dc98b6bbde2f92e63d500d5e6015184bb105

Yes this has been bugging me as well, and probably we should put this
patch upstream.

However I will note that Alan submitted an issue about the underlying
issue:

https://listman.redhat.com/archives/libguestfs/2022-September/030074.html
https://github.com/asomers/mockall/issues/414

It's marked as fixed, but for some reason that didn't seem to fix the
tests - I'm still seeing the unused 'expect' here, even after
completely deleting the cargo cache.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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