Enum Reachability 

pub enum Reachability {
    Reachable,
    Unreachable,
    Indeterminate {
        missing: Vec<ID>,
    },
}

Verdict of a bounded, tree-scoped reachability query (check_targets_reachable_from).

The three states exist so a caller can tell a proven negative apart from “not enough local history to decide” — a distinction that matters for a sync system, where the latter is transient and self-heals once more of the tree arrives.

Variants

Reachable

Every target is an ancestor-or-equal of some from entry, proven against fully-present history within the height bound.

Unreachable

Proven negative: the region at or above the target floor was fully present locally and at least one target is not an ancestor of from (e.g. a snapshot regression, or a foreign/fabricated tip).

Indeterminate

Undecidable from local history: a target, a from tip, or an ancestor needed to reach a target is missing locally. missing is the set of entries whose absence blocked the decision — the caller should sync these and re-check. It is the current blocking frontier, not necessarily the whole gap: fetching it may reveal a further layer. The height bound keeps this set small.

Fields

missing: Vec<ID>

Entries that must be synced before the query can be decided.

Trait Implementations

impl Clone for Reachability

fn clone(&self) -> Reachability

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Reachability

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

Formats the value using the given formatter.

impl PartialEq for Reachability

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for Reachability

impl StructuralPartialEq for Reachability