Enum tvix_eval::CatchableErrorKind

pub enum CatchableErrorKind {
    Throw(String),
    AssertionFailed,
    NixPathResolution(String),
}

“CatchableErrorKind” errors – those which can be detected by builtins.tryEval.

Note: this type is deliberately not incorporated as a variant of ErrorKind, because then Result<Value,ErrorKind> would have redundant representations for catchable errors, which would make it too easy to handle errors incorrectly:

• Ok(Value::Catchable(cek))
• Err(ErrorKind::ThisVariantDoesNotExist(cek))

Because CatchableErrorKind is not a variant of ErrorKind, you will often see functions which return a type like:

Result<Result<T,CatchableErrorKind>,ErrorKind>

… where T is any type other than Value. This is unfortunate, because Rust’s magic ?-syntax does not work on nested Result values like this.

TODO(amjoseph): investigate result<T,Either<CatchableErrorKind,ErrorKind>>

Variants

Throw(String)

AssertionFailed

NixPathResolution(String)

Resolving a user-supplied angle brackets path literal failed in some way.

Trait Implementations

impl Clone for CatchableErrorKind

fn clone(&self) -> CatchableErrorKind

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for CatchableErrorKind

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

Formats the value using the given formatter.

impl From<CatchableErrorKind> for Value

fn from(c: CatchableErrorKind) -> Value

Converts to this type from the input type.