Struct snafu::Whatever

source ·
pub struct Whatever { /* private fields */ }
Expand description

A basic error type that you can use as a first step to better error handling.

You can use this type in your own application as a quick way to create errors or add basic context to another error. This can also be used in a library, but consider wrapping it in an opaque error to avoid putting the SNAFU crate in your public API.

§Examples

use snafu::prelude::*;

type Result<T, E = snafu::Whatever> = std::result::Result<T, E>;

fn subtract_numbers(a: u32, b: u32) -> Result<u32> {
    if a > b {
        Ok(a - b)
    } else {
        whatever!("Can't subtract {a} - {b}")
    }
}

fn complicated_math(a: u32, b: u32) -> Result<u32> {
    let val = subtract_numbers(a, b).whatever_context("Can't do the math")?;
    Ok(val * 2)
}

See whatever! for detailed usage instructions.

§Limitations

When wrapping errors, only the backtrace from the shallowest function is guaranteed to be available. If you need the deepest possible trace, consider creating a custom error type and using #[snafu(backtrace)] on the source field. If a best-effort attempt is sufficient, see the backtrace method.

When the standard library stabilizes backtrace support, this behavior may change.

Implementations§

source§

impl Whatever

source

pub fn backtrace(&self) -> Option<&Backtrace>

Gets the backtrace from the deepest Whatever error. If none of the underlying errors are Whatever, returns the backtrace from when this instance was created.

Trait Implementations§

source§

impl Debug for Whatever

source§

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
source§

impl Display for Whatever

source§

fn fmt(&self, __snafu_display_formatter: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
source§

impl Error for Whatever
where Self: Debug + Display,

source§

fn description(&self) -> &str

👎Deprecated since 1.42.0: use the Display impl or to_string()
source§

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
source§

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any. Read more
source§

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
source§

impl ErrorCompat for Whatever

source§

fn backtrace(&self) -> Option<&Backtrace>

Returns a Backtrace that may be printed.
source§

fn iter_chain(&self) -> ChainCompat<'_, '_>
where Self: AsErrorSource,

Returns an iterator for traversing the chain of errors, starting with the current error and continuing with recursive calls to Error::source. Read more
source§

impl FromString for Whatever

source§

type Source = Box<dyn Error>

The underlying error
source§

fn without_source(message: String) -> Self

Create a brand new error from the given string
source§

fn with_source(error: Self::Source, message: String) -> Self

Wrap an existing error with the given string

Auto Trait Implementations§

Blanket Implementations§

source§

impl<T> Any for T
where T: 'static + ?Sized,

source§

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
source§

impl<T> AsErrorSource for T
where T: Error + 'static,

source§

fn as_error_source(&self) -> &(dyn Error + 'static)

For maximum effectiveness, this needs to be called as a method to benefit from Rust’s automatic dereferencing of method receivers.
source§

impl<T> Borrow<T> for T
where T: ?Sized,

source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
source§

impl<T> BorrowMut<T> for T
where T: ?Sized,

source§

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
source§

impl<T> From<T> for T

source§

fn from(t: T) -> T

Returns the argument unchanged.

source§

impl<T, U> Into<U> for T
where U: From<T>,

source§

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

source§

impl<T> ToString for T
where T: Display + ?Sized,

source§

default fn to_string(&self) -> String

Converts the given value to a String. Read more
source§

impl<T, U> TryFrom<U> for T
where U: Into<T>,

source§

type Error = Infallible

The type returned in the event of a conversion error.
source§

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
source§

impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

source§

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
source§

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.