Mailing List Archive: [PATCH] rust: error: allow specifying error type on `Result`

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

May 2, 2023, 6:15 AM

Post #1 of 6 (13 views)

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@google.com>
---
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
--
2.40.1.495.gc816e09b53d-goog

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

lina at asahilina

May 2, 2023, 8:15 AM

Post #2 of 6 (13 views)

Permalink

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@google.com>
> ---
> 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@asahilina.net>

~~ Lina

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

benno.lossin at proton

May 2, 2023, 12:15 PM

Post #3 of 6 (13 views)

Permalink

On 02.05.23 14:40, 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@google.com>

Reviewed-by: Benno Lossin <benno.lossin@proton.me>

> ---
> 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
> --
> 2.40.1.495.gc816e09b53d-goog
>

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

gary at garyguo

May 8, 2023, 6:15 AM

Post #4 of 6 (13 views)

Permalink

On Tue, 2 May 2023 12:40:15 +0000
Alice Ryhl <aliceryhl@google.com> 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@google.com>

Reviewed-by: Gary Guo <gary@garyguo.net>

> ---
> 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

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

nmi at metaspace

May 15, 2023, 12:15 PM

Post #5 of 6 (13 views)

Permalink

Alice Ryhl <aliceryhl@google.com> writes:

> 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@google.com>
> ---

Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>

> 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

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

miguel.ojeda.sandonis at gmail

May 31, 2023, 10:15 AM

Post #6 of 6 (13 views)

Permalink

On Tue, May 2, 2023 at 2:40?PM Alice Ryhl <aliceryhl@google.com> 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@google.com>

Applied to `rust-next` -- thanks everyone!

Cheers,
Miguel