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//! Error types for instance operations.
use std::fmt;
use panproto_gat::Name;
/// Errors from instance construction or manipulation.
#[derive(Debug, thiserror::Error)]
#[non_exhaustive]
pub enum InstError {
/// A node ID was referenced but not found.
#[error("node not found: {0}")]
NodeNotFound(u32),
/// A vertex ID was referenced but not found in the schema.
#[error("vertex not found in schema: {0}")]
VertexNotFound(String),
/// The root node is missing.
#[error("root node missing from instance")]
MissingRoot,
/// An arc references a nonexistent node.
#[error("dangling arc: ({src}, {tgt})")]
DanglingArc {
/// Source node ID.
src: u32,
/// Target node ID.
tgt: u32,
},
/// Internal hom evaluation failed.
#[error("eval_hom failed: {0}")]
EvalHom(String),
}
/// Errors from the restrict operation.
#[derive(Debug, thiserror::Error)]
#[non_exhaustive]
pub enum RestrictError {
/// No edge found between two vertices after ancestor contraction.
#[error("no edge found between {src} and {tgt} in target schema")]
NoEdgeFound {
/// Source vertex anchor.
src: String,
/// Target vertex anchor.
tgt: String,
},
/// Multiple edges found without a resolver entry.
#[error("ambiguous edge between {src} and {tgt}: {count} candidates")]
AmbiguousEdge {
/// Source vertex anchor.
src: String,
/// Target vertex anchor.
tgt: String,
/// Number of candidate edges.
count: usize,
},
/// The root was pruned during restriction.
#[error("root node was pruned during restriction")]
RootPruned,
/// Fan reconstruction failed.
#[error("fan reconstruction failed for hyper-edge {hyper_edge_id}: {detail}")]
FanReconstructionFailed {
/// The hyper-edge ID.
hyper_edge_id: String,
/// Details about the failure.
detail: String,
},
/// Cartesian product exceeded the configured size limit.
#[error("product size {actual} exceeds limit {limit} for vertex {vertex}")]
ProductSizeExceeded {
/// The target vertex whose fiber product is too large.
vertex: String,
/// The actual product size.
actual: usize,
/// The configured limit.
limit: usize,
},
/// Multi-element fiber encountered where only single-element fibers
/// are supported (e.g., W-type right Kan extension).
#[error("multi-element fiber for vertex {vertex}: {count} source vertices")]
MultiElementFiber {
/// The target vertex with multiple preimages.
vertex: String,
/// Number of source vertices in the fiber.
count: usize,
},
/// A source node's anchor is neither remapped by `vertex_remap` nor
/// present in `surviving_verts`, so a *total* operation (left Kan
/// extension `Sigma_F`, right Kan extension `Pi_F`) has no target
/// vertex to map it to. These operations never drop data silently;
/// they report the unmapped anchor instead.
#[error("node {node_id} has anchor `{anchor}` that is neither remapped nor surviving")]
UnmappedAnchor {
/// The anchor that has no image in the target schema.
anchor: Name,
/// The offending source node ID.
node_id: u32,
},
/// Two source vertices in a right Kan extension (`Pi_F`) fiber contribute
/// the same column with conflicting values, so the product-row attribute
/// merge would have to silently overwrite one. The merge rejects instead.
#[error(
"attribute collision on column `{column}` for vertex `{vertex}`: \
fiber sources disagree on its value"
)]
AttributeCollision {
/// The target vertex whose fiber product collides.
vertex: String,
/// The colliding column name.
column: String,
},
/// A vertex map sends two or more distinct source vertices to a single
/// target vertex. The W-type right Kan extension ([`wtype_pi`]) is only
/// defined here for vertex-injective migrations, since a non-injective
/// map would require constructing a product of subtrees.
///
/// [`wtype_pi`]: crate::wtype_pi
#[error(
"non-injective vertex map: {} source vertices map to target `{target}`",
sources.len()
)]
NonInjectiveVertexMap {
/// The target vertex receiving multiple source vertices.
target: Name,
/// The source vertices in the fiber (sorted for determinism).
sources: Vec<Name>,
},
}
/// Errors from JSON parsing.
#[derive(Debug, thiserror::Error)]
#[non_exhaustive]
pub enum ParseError {
/// The root vertex was not found in the schema.
#[error("root vertex not found in schema: {0}")]
RootVertexNotFound(String),
/// Expected a JSON object.
#[error("expected JSON object at path {path}")]
ExpectedObject {
/// JSON path where the error occurred.
path: String,
},
/// Expected a JSON array.
#[error("expected JSON array at path {path}")]
ExpectedArray {
/// JSON path where the error occurred.
path: String,
},
/// An edge references an unknown vertex kind.
#[error("unknown edge target at path {path}: {detail}")]
UnknownEdgeTarget {
/// JSON path where the error occurred.
path: String,
/// Details.
detail: String,
},
/// A value could not be parsed.
#[error("invalid value at path {path}: {detail}")]
InvalidValue {
/// JSON path where the error occurred.
path: String,
/// Details.
detail: String,
},
/// JSON structure error.
#[error("JSON error: {0}")]
Json(#[from] serde_json::Error),
}
/// A validation error found when checking a W-type instance against a schema.
#[derive(Debug, Clone, PartialEq, Eq)]
#[non_exhaustive]
pub enum ValidationError {
/// A node's anchor vertex is not in the schema.
InvalidAnchor {
/// The offending node ID.
node_id: u32,
/// The anchor that was not found.
anchor: String,
},
/// An arc's edge is not in the schema.
InvalidEdge {
/// Parent node ID.
parent: u32,
/// Child node ID.
child: u32,
/// Details.
detail: String,
},
/// The root node is not present in the node set.
MissingRoot,
/// A child node is unreachable from the root.
UnreachableNode {
/// The unreachable node ID.
node_id: u32,
},
/// A required edge is missing from a node.
MissingRequiredEdge {
/// The node ID.
node_id: u32,
/// Description of the missing edge.
edge: String,
},
/// Parent map inconsistency.
ParentMapInconsistent {
/// The node with the inconsistency.
node_id: u32,
/// Details.
detail: String,
},
/// Fan references a nonexistent node.
InvalidFan {
/// The hyper-edge ID.
hyper_edge_id: String,
/// Details.
detail: String,
},
}
impl fmt::Display for ValidationError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
Self::InvalidAnchor { node_id, anchor } => {
write!(f, "node {node_id} has invalid anchor: {anchor}")
}
Self::InvalidEdge {
parent,
child,
detail,
} => write!(f, "invalid edge ({parent}, {child}): {detail}"),
Self::MissingRoot => write!(f, "root node is missing"),
Self::UnreachableNode { node_id } => {
write!(f, "node {node_id} is unreachable from root")
}
Self::MissingRequiredEdge { node_id, edge } => {
write!(f, "node {node_id} missing required edge: {edge}")
}
Self::ParentMapInconsistent { node_id, detail } => {
write!(f, "parent map inconsistency at node {node_id}: {detail}")
}
Self::InvalidFan {
hyper_edge_id,
detail,
} => write!(f, "invalid fan for hyper-edge {hyper_edge_id}: {detail}"),
}
}
}