Enum Chooser 

pub enum Chooser {
    Record {
        rng: SeededRng,
        seed: SchedSeed,
        choices: Vec<ChoicePoint>,
    },
    Replay {
        trace: SchedTrace,
        pos: usize,
    },
}

The decision choke point: records (seeded) or replays scheduling choices.

THE single source of nondeterminism in the runtime — every scheduler choice goes through Chooser::decide. Nothing else draws entropy.

Variants

Record

Recording: draw from the seeded RNG and log each choice.

Fields

rng: SeededRng

seed: SchedSeed

choices: Vec<ChoicePoint>

Replay

Replaying: re-issue the recorded choices, asserting the shapes still match.

Fields

trace: SchedTrace

pos: usize

Implementations

impl Chooser

pub fn record(seed: SchedSeed) -> Self

A fresh recording chooser seeded by seed.

pub fn replay(trace: SchedTrace) -> Self

A replaying chooser that re-issues the decisions in trace.

pub fn decide(&mut self, kind: ChoiceKind, options: usize) -> usize

Resolve one decision among options choices, returning the chosen index.

Record mode draws from the seeded RNG and logs the choice. Replay mode returns the recorded choice, panicking if the decision shape diverges from what was recorded (a different kind or options count, or running past the end of the trace).

pub fn into_trace(self) -> SchedTrace

Finish and return the trace (returns the original trace for a replay chooser).

Trait Implementations

impl Clone for Chooser

fn clone(&self) -> Chooser

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Chooser

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

Formats the value using the given formatter.