diff mbox series

rust: error: allow specifying error type on `Result`

Message ID 20230502124015.356001-1-aliceryhl@google.com
State New
Headers
Series rust: error: allow specifying error type on `Result` |

Commit Message

Alice Ryhl May 2, 2023, 12:40 p.m. UTC 
  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(-)


base-commit: ea76e08f4d901a450619831a255e9e0a4c0ed162

Comments

Asahi Lina May 2, 2023, 1:59 p.m. UTC | #1 
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
Benno Lossin May 2, 2023, 6:05 p.m. UTC | #2 
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
>
Gary Guo May 8, 2023, 11:39 a.m. UTC | #3 
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
Andreas Hindborg May 15, 2023, 7:09 p.m. UTC | #4 
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
Miguel Ojeda May 31, 2023, 5:09 p.m. UTC | #5 
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
diff mbox series

Patch

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.