Enum DurationP 

pub enum DurationP {
    Measured(Duration),
    Projected(Duration),
}

Seconds, plus how we know them (COST-1).

The labelling rule is the enum: every way of building one of these names a provenance, because there is no other variant to reach and no From<Duration>/Default to fall into. cost.py achieved the same thing with a field that had no default, so Duration(3600) raised TypeError — the whole rule collapses the moment an unlabelled duration can be written, because the label that goes missing is always the weaker one, and here it cannot be written.

Wrapping std::time::Duration also retires the Python’s negativity check: a negative duration is not a value this type can hold, so an inverted clock is caught at duration_of_secs_f64 or never enters at all.

Provenance cannot be omitted (COST-1)

“No unlabelled constructor” is a claim about what does not exist, so it is checked by programs that do not build:

Each carries its expected error code, because a bare compile_fail passes for any build failure at all — a typo in the test would leave the guard green.

// There is no `From<Duration> for DurationP`, so a bare span cannot become a
// labelled one by coercion.
let unlabelled: DurationP = Duration::from_secs(3600).into();

// No `Default` either. A default would have to pick a provenance, and the one it
// would pick is the stronger claim.
let unlabelled = DurationP::default();

The positive case, for contrast — naming the provenance is the only way in, and it is one word:

let timed = DurationP::Measured(Duration::from_secs(3600));
assert_eq!(timed.provenance(), Provenance::Measured);

Variants

Measured(Duration)

A clock ran and this is what it read.

Projected(Duration)

A hypothetical: an estimate’s input, or a documented minimum nobody timed.

Implementations

impl DurationP

pub fn measured_secs_f64(seconds: f64) -> Result<DurationP, Error>

A timed phase, from seconds a caller measured as a float.

Fallible because the float is: see duration_of_secs_f64.

pub fn projected_secs_f64(seconds: f64) -> Result<DurationP, Error>

A hypothetical phase, from seconds a caller supplied as a float.

pub fn duration(self) -> Duration

The span, without its label. Named so a call site that drops the provenance is visible as one.

pub fn provenance(self) -> Provenance

How this duration is known.

pub fn seconds(self) -> Decimal

The span as exact decimal seconds, for the money path.

pub fn seconds_f64(self) -> f64

The span as an f64, for a JSON envelope.

Lossy, and named so, exactly like ResidencyComparison::break_even_seconds_f64. The exact answer is DurationP::seconds; this exists because cli.py:743 emits a line item’s duration.seconds as a JSON number and the two clients’ envelopes have to be substitutable. Seconds, not dollars — no money figure has an f64 accessor (COST-2), and that asymmetry is the whole rule: a consumer doing arithmetic on a duration should not have to branch on which client produced the envelope, while a consumer doing arithmetic on a dollar figure should be reading the string and told so.

(cli.py line numbers resolve at git show 'c4d396e^:clients/python/src/microvms_agentd/cli.py' — the retired oracle.)

pub fn is_measured(self) -> bool

True only for a timed span. Read by CostReport::fully_measured.

Trait Implementations

impl Clone for DurationP

fn clone(&self) -> DurationP

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for DurationP

impl Debug for DurationP

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

Formats the value using the given formatter.

impl Display for DurationP

The Python’s f"{seconds:g}s ({provenance})", so a report line reads the same in either client.

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

Formats the value using the given formatter.

impl Eq for DurationP

impl Hash for DurationP

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 DurationP

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for DurationP