Enum RuntimeLane 

pub enum RuntimeLane {
    Legacy,
    Structured,
    Asupersync,
}

Runtime lane for the Asupersync migration rollout.

Controls which subscription/effect execution backend is active. The default is Structured, reflecting the completed CancellationToken migration (bd-3tmu4).

Migration rollout

1. Legacy — pre-migration thread-based subscriptions with manual stop coordination
2. Structured — CancellationToken-backed subscriptions (current default after bd-3tmu4)
3. Asupersync — full Asupersync-native execution (future)

Selection is logged at startup so operators can tell which lane is active. Fallback from Asupersync → Structured → Legacy is automatic on error.

Variants

Legacy

Pre-migration behavior: thread-based subscriptions with manual stop coordination. This is the safe default that preserves all existing semantics.

Structured

Structured cancellation: subscriptions use CancellationToken internally. Externally observable behavior is identical to Legacy.

Asupersync

Full Asupersync-native execution (reserved for future use). Falls back to Structured if Asupersync primitives are unavailable.

Implementations

impl RuntimeLane

pub fn resolve(self) -> Self

Resolve the effective lane, applying fallback rules.

If the requested lane is not yet implemented, falls back to the highest available lane. Currently: Asupersync → Structured.

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

Returns a human-readable label for logging.

pub fn uses_structured_cancellation(self) -> bool

Check if this lane uses structured cancellation (CancellationToken).

pub fn from_env() -> Option<Self>

Read the lane from the FTUI_RUNTIME_LANE environment variable.

Accepted values (case-insensitive): legacy, structured, asupersync. Returns None if the variable is unset or contains an unrecognized value.

pub fn parse(s: &str) -> Option<Self>

Parse a lane name (case-insensitive).

Returns None for unrecognized values.

Trait Implementations

impl Clone for RuntimeLane

fn clone(&self) -> RuntimeLane

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for RuntimeLane

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

Formats the value using the given formatter.

impl Default for RuntimeLane

fn default() -> RuntimeLane

Returns the “default value” for a type.

impl Display for RuntimeLane

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

Formats the value using the given formatter.

impl Hash for RuntimeLane

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for RuntimeLane

fn eq(&self, other: &RuntimeLane) -> 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 Copy for RuntimeLane

impl Eq for RuntimeLane

impl StructuralPartialEq for RuntimeLane