Enum InjectionStrategy 

pub enum InjectionStrategy {
    Never,
    AtSequence(u64),
    AtPoint(AwaitPoint),
    EveryNth(u64),
    AllPoints,
    RandomSample(usize),
    SpecificPoints(Vec<u64>),
    FirstN(usize),
    Probabilistic(f64),
    WindowAround {
        center: u64,
        radius: u64,
    },
    ExceptFirst(usize),
    LastN(usize),
}

Strategy for selecting which await points to inject cancellation at.

This controls which points are selected for injection during a test run. Use with InjectionRunner::run_with_injection for automated test execution.

Variants

Never

Never inject cancellation (recording mode only).

AtSequence(u64)

Inject at a specific await point sequence number.

AtPoint(AwaitPoint)

Inject at a specific await point.

EveryNth(u64)

Inject at every Nth await point.

AllPoints

Test every await point (most thorough, N+1 runs for N await points).

RandomSample(usize)

Test n randomly-selected await points using deterministic RNG.

SpecificPoints(Vec<u64>)

Test only specified await points.

FirstN(usize)

Test first n await points.

Probabilistic(f64)

Each await point has probability p (0.0-1.0) of injection.

WindowAround

Test a window of points around a center point.

Selects all recorded points in [center - radius, center + radius]. Useful for targeting a specific code region (e.g., around a known cancel checkpoint) without testing every point in the entire run.

Fields

center: u64

The center await point sequence number.

radius: u64

Number of points on each side to include.

ExceptFirst(usize)

Skip the first N points, test the rest.

Useful for bypassing initialization and focusing on steady-state or cleanup/finalization phases where cancellation handling matters most.

LastN(usize)

Test only the last N recorded await points.

Targets the tail of execution — typically the finalization and cleanup phases — where cancel-correctness bugs are most common.

Implementations

impl InjectionStrategy

pub fn select_points(&self, recorded: &[u64], seed: u64) -> Vec<u64>

Selects the await points to test based on this strategy.

Arguments

• recorded - The await points recorded during the recording run
• seed - Deterministic seed for random selection

Returns

A vector of await point sequence numbers to test

Trait Implementations

impl Clone for InjectionStrategy

fn clone(&self) -> InjectionStrategy

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for InjectionStrategy

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

Formats the value using the given formatter.

impl Default for InjectionStrategy

fn default() -> InjectionStrategy

Returns the “default value” for a type.