Enum DagError 

#[non_exhaustive]
pub enum DagError {
    DuplicateId(CausalId),
    MissingPredecessor {
        child: CausalId,
        parent: CausalId,
    },
    SelfReference(CausalId),
}

Error returned by CausalDag::append.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

DuplicateId(CausalId)

A record with this CausalId already exists in the DAG. Append-only invariant: duplicate IDs are forbidden.

MissingPredecessor

The record references a predecessor that has not yet been inserted. Physical axiom: a cause must exist before an effect can reference it.

Fields

child: CausalId

The record being inserted.

parent: CausalId

The predecessor that was not found in the DAG.

SelfReference(CausalId)

The record lists its own CausalId in its predecessor set Π. A causal self-loop violates the acyclicity invariant.

Trait Implementations

impl Clone for DagError

fn clone(&self) -> DagError

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for DagError

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

Formats the value using the given formatter.

impl Display for DagError

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

Formats the value using the given formatter.

impl Error for DagError

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

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

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

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

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

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.