Enum CspError 

pub enum CspError {
    Unsatisfiable,
    BudgetExceeded,
    InvalidInput {
        detail: String,
    },
    Timeout,
}

Unified error family for Csp/Sudoku/Futoshiki operations exposed across the PyO3 and wasm boundaries.

Deliberately flat (no nested Box<dyn Error> source chaining) — every downstream binding needs to pattern-match this by value to pick an exception class / HTTP status, and a flat enum is the cheapest thing that supports that without reflection.

Variants

Unsatisfiable

No solution exists under the current constraints/propagation. Maps from the crate’s existing crate::Unsatisfiable marker (kept as the internal propagation-layer type; this is the binding-facing supertype).

BudgetExceeded

The search aborted after crate::SolveConfig::node_budget nodes; any solutions returned are best-so-far, not verified optimal or exhaustive. Distinct from Unsatisfiable — conflating the two was Pass-1 finding R8/F12 (AssignmentBuilder and SudokuCSP both did this).

InvalidInput

A caller-supplied argument was structurally invalid: an out-of-range position, a malformed numeric key, an unknown enum value, mismatched dimensions, etc. Carries a human-readable detail string (never leaked Rust-internal panic/debug detail — callers construct this variant explicitly, it is never built from a caught panic).

Fields

detail: String

What was wrong, safe to surface to an API client verbatim.

Timeout

A wall-clock deadline elapsed before the search produced a result. Distinct from BudgetExceeded (a node-count budget, checked at the same cadence but triggered by count not time). Forward-declared for the wall-clock time_budget deferred item (synthesis-pass1 §3.1 N11) — the cooperative cancellation flag a caller’s HTTP-layer timeout should set, rather than the FastAPI asyncio.wait_for theater that today cancels only the awaiting coroutine, never the search (Pass-1 fastapi-service F3 / pyo3-boundary).

Implementations

impl CspError

pub const fn code(&self) -> &'static str

Stable machine-readable discriminant. This exact string is what py/errors.rs’s exception class names are derived from, what a wasm CspJsError.code would carry across that boundary, and what a FastAPI JSON error envelope’s error.code field would be — the single vocabulary every layer of the taxonomy shares.

pub fn invalid_input(detail: impl Into<String>) -> Self

Convenience constructor — the one place format! call sites collapse into, instead of each binding hand-rolling its own PyValueError::new_err(format!(...)) / JsError::new(&format!(...)).

Trait Implementations

impl Clone for CspError

fn clone(&self) -> CspError

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for CspError

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

Formats the value using the given formatter.

impl Display for CspError

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

Formats the value using the given formatter.

impl Error for CspError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl From<AssignmentError> for CspError

AssignmentBuilder’s error family converts too, so py//wasm call sites that touch the assignment/COP path get the same typed exceptions as the Sudoku path for free. Note this conversion is itself evidence of Pass-1 finding R8: Infeasible collapses onto Unsatisfiable here because AssignmentError has no distinct budget-exhaustion variant yet — fixing that is a separate, already ledgered item, not silently patched over by this mapping.

fn from(e: AssignmentError) -> Self

Converts to this type from the input type.

impl From<Unsatisfiable> for CspError

The propagation layer’s existing marker type converts losslessly — every current ?-using call site (Csp::propagate, Csp::propagate_with) keeps compiling unchanged; only the bindings need to switch their map_err target.

fn from(_: Unsatisfiable) -> Self

Converts to this type from the input type.

impl PartialEq for CspError

fn eq(&self, other: &CspError) -> 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 StructuralPartialEq for CspError