[−][src]Module snafu::guide::upgrading

Upgrading from previous releases

Version 0.3 → 0.4

Context vs. IntoError

The Context type and related From implementations have been removed in favor of the IntoError trait. If you were making use of this for custom conversions, you will need to update your trait bounds:

Before

ⓘThis example is not tested
fn example<C, E>(context: C) -> MyType<E>
where
    snafu::Context<SomeError, C>: Into<E>;

After

ⓘThis example is not tested
fn example<C, E>(context: C) -> MyType<E>
where
    C: snafu::IntoError<E, Source = SomeError>,
    E: std::error::Error + snafu::ErrorCompat;

Borrow<std::error::Error>

SNAFU no longer generates Borrow<std::error::Error> implementations for SNAFU error types (sorry for the whiplash if you were affected by this when upgrading to 0.3).

Version 0.2 → 0.3

Minimal changes should be required: if you previously implemented Borrow<std::error::Error> for a SNAFU error type, you should remove that implementation and allow SNAFU to implement it for you.

Version 0.1 → 0.2

Support for the snafu::display attribute was removed as this type of attribute was never intended to be supported. Since this required a SemVer-incompatible version, the attribute format has also been updated and normalized.

  1. Attributes have been renamed

    • snafu_display and snafu::display became snafu(display).
    • snafu_visibility became snafu(visibility)
    • snafu_backtrace became snafu(backtrace)

  2. Support for snafu_display with individually-quoted format arguments was removed. Migrate to either the "clean" or "all one string" styles, depending on what version of Rust you are targeting.

Before

ⓘThis example is not tested
#[derive(Debug, Snafu)]
enum DisplayUpdate {
    #[snafu::display("Format and {}", argument)]
    CleanStyle { argument: i32 },

    #[snafu_display("Format and {}", "argument")]
    QuotedArgumentStyle { argument: i32 },

    #[snafu_display = r#"("Format and {}", argument)"#]
    AllOneStringStyle { argument: i32 },
}
ⓘThis example is not tested
#[derive(Debug, Snafu)]
enum VisibilityUpdate {
    #[snafu_visibility(pub(crate))]
    CleanStyle,

    #[snafu_visibility = "pub(crate)"]
    AllOneStringStyle,
}

After

ⓘThis example is not tested
#[derive(Debug, Snafu)]
enum DisplayUpdate {
    #[snafu(display("Format and {}", argument))]
    CleanStyle { argument: i32 },

    #[snafu(display = r#"("Format and {}", argument)"#)]
    QuotedArgumentStyle { argument: i32 },

    #[snafu(display = r#"("Format and {}", argument)"#)]
    AllOneStringStyle { argument: i32 },
}
ⓘThis example is not tested
#[derive(Debug, Snafu)]
enum VisibilityUpdate {
    #[snafu(visibility(pub(crate)))]
    CleanStyle,

    #[snafu(visibility = "pub(crate)")]
    AllOneStringStyle,
}