Re: [PATCH] rust: error: allow specifying error type on `Result`

From: Asahi Lina
Date: Tue May 02 2023 - 09:59:37 EST


On 02/05/2023 21.40, Alice Ryhl wrote:
Currently, if the `kernel::error::Result` type is in scope (which is
often is, since it's in the kernel's prelude), you cannot write
`Result<T, SomeOtherErrorType>` when you want to use a different error
type than `kernel::error::Error`.

To solve this we change the error type from being hard-coded to just
being a default generic parameter. This still lets you write `Result<T>`
when you just want to use the `Error` error type, but also lets you
write `Result<T, SomeOtherErrorType>` when necessary.

Signed-off-by: Alice Ryhl <aliceryhl@xxxxxxxxxx>
---
rust/kernel/error.rs | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs
index 5f4114b30b94..01dd4d2f63d2 100644
--- a/rust/kernel/error.rs
+++ b/rust/kernel/error.rs
@@ -177,7 +177,7 @@ impl From<core::convert::Infallible> for Error {
/// Note that even if a function does not return anything when it succeeds,
/// it should still be modeled as returning a `Result` rather than
/// just an [`Error`].
-pub type Result<T = ()> = core::result::Result<T, Error>;
+pub type Result<T = (), E = Error> = core::result::Result<T, E>;
/// Converts an integer as returned by a C kernel function to an error if it's negative, and
/// `Ok(())` otherwise.

base-commit: ea76e08f4d901a450619831a255e9e0a4c0ed162

Reviewed-by: Asahi Lina <lina@xxxxxxxxxxxxx>

~~ Lina