Enum KgMiss 

#[non_exhaustive]
pub enum KgMiss {
    SubjectNotFound,
    GraphEmpty,
}

Which of the two distinct “no triples came back” outcomes a kg_query hit.

Why (#4775): both outcomes returned the same “Knowledge graph is empty” hint, and for the common case — a graph with facts, queried for a subject it does not hold — that hint states something the handler can prove false. A caller that believes it wastes a kg_bootstrap on an already-seeded graph instead of listing the subjects that are there. What: the discriminator behind kg_query’s graph_state response field. Self::classify decides which one applies; Self::wire_value and Self::hint are the two strings that reach the caller. Marked #[non_exhaustive] so a future third outcome is not a breaking change. Test: kg_miss_classify_distinguishes_empty_graph_from_missing_subject.

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.

SubjectNotFound

The graph holds active triples, just none for the queried subject.

GraphEmpty

The graph holds no active triples at all.

Implementations

impl KgMiss

pub fn classify( subject_triples: usize, total_active_triples: usize, ) -> Option<Self>

Classify a kg_query result; None means the subject matched.

Why (#4775): emptiness is a whole-graph property, so it cannot be read off the per-subject result alone — that conflation is the defect. Both counts are required, and taking them as parameters keeps the decision pure and directly testable without a live palace. What: None when subject_triples > 0. Otherwise GraphEmpty iff the whole graph reports zero active triples, else SubjectNotFound. Test: kg_miss_classify_distinguishes_empty_graph_from_missing_subject.

pub fn wire_value(self) -> &'static str

The string emitted as kg_query’s graph_state field.

pub fn hint(self) -> &'static str

The recovery hint that matches this outcome.

Trait Implementations

impl Clone for KgMiss

fn clone(&self) -> KgMiss

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for KgMiss

impl Debug for KgMiss

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

Formats the value using the given formatter.

impl Eq for KgMiss

impl PartialEq for KgMiss

fn eq(&self, other: &KgMiss) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for KgMiss