2023-05-02 12:46:06

by Alice Ryhl

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

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 <[email protected]>
---
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


2023-05-02 14:10:07

by Asahi Lina

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

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 <[email protected]>
> ---
> 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 <[email protected]>

~~ Lina

2023-05-02 18:10:16

by Benno Lossin

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

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 <[email protected]>

Reviewed-by: Benno Lossin <[email protected]>

> ---
> 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
>

2023-05-08 12:07:10

by Gary Guo

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

On Tue, 2 May 2023 12:40:15 +0000
Alice Ryhl <[email protected]> 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 <[email protected]>

Reviewed-by: Gary Guo <[email protected]>

> ---
> 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

2023-05-15 19:21:11

by Andreas Hindborg

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


Alice Ryhl <[email protected]> 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 <[email protected]>
> ---

Reviewed-by: Andreas Hindborg <[email protected]>

> 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


2023-05-31 17:17:10

by Miguel Ojeda

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

On Tue, May 2, 2023 at 2:40 PM Alice Ryhl <[email protected]> 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 <[email protected]>

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

Cheers,
Miguel