Re: [PATCH v3 3/7] rust: property: Introduce PropertyGuard

Remo Senekowitsch
2025-04-28T21:50:33Z

On Mon Apr 28, 2025 at 11:21 PM CEST, Danilo Krummrich wrote:
> On Mon, Apr 28, 2025 at 03:48:40PM -0500, Rob Herring wrote:
>>
>> One thing that's really hard to debug in C drivers is where an
>> error came from. You can for example turn on initcall_debug and see that
>> a driver probe returned an error. It's virtually impossible to tell
>> where that originated from. The only way to tell is with prints. That is
>> probably the root of why probe has so many error prints. I think we can
>> do a lot better with rust given Result can hold more than just an int.
>
> This I fully agree with, not sure if the solution is to put more stuff into the
> Result type though. However, there are things like #[track_caller] (also
> recently mentioned by Benno), which might be a good candidate for improving this
> situation.
>
> As mentioned, for now let's go with
>
> pub fn required_by(self, dev: &Device) -> Result<T>
>
> additional to required() for this purpose to get a proper dev_err() print.

Could it make sense to _replace_ `required` with `required_by` ?
Otherwise `required` sits a little awkwardly between `optional` and
`required_by`. I can't think of a situation where `required` would be
preferred.