Enum BuildError 

pub enum BuildError {
    EmptyBuilder,
    FirstStepNotContextFree {
        first_kind: PlanNodeKind,
    },
    ZeroDepth,
    InvalidSetOpOperand {
        reason: String,
    },
}

Errors produced when a QueryBuilder fails to materialise a valid plan.

Every error reflects a structural invariant the executor relies on. None of these errors abort the calling thread — they are returned via QueryBuilder::build so the caller can adjust the user query and retry.

Variants

EmptyBuilder

The builder has no steps. Calling QueryBuilder::build on a freshly constructed QueryBuilder::new without any other method calls produces this error.

FirstStepNotContextFree

The first step of the chain is not context-free.

The chain executor walks steps from left to right, threading each step’s output into the next step’s input. The first step therefore cannot depend on an inherited input set — only PlanNode::NodeScan and PlanNode::SetOp satisfy that contract (see PlanNode::is_context_free).

Fields

first_kind: PlanNodeKind

Name of the offending step variant for diagnostic purposes (e.g. "Filter", "EdgeTraversal", "Chain").

ZeroDepth

An PlanNode::EdgeTraversal step was added with max_depth = 0.

max_depth = 0 would yield an empty result set unconditionally — the executor short-circuits, so the plan is unambiguously a user error. The builder rejects it at construction time.

InvalidSetOpOperand

A nested sub-plan supplied to QueryBuilder::union, QueryBuilder::intersect, or QueryBuilder::difference failed the same context-free validation as a chain’s first step.

Fields

reason: String

Human-readable explanation lifted from the inner BuildError.

Trait Implementations

impl Clone for BuildError

fn clone(&self) -> BuildError

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for BuildError

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

Formats the value using the given formatter.

impl Display for BuildError

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

Formats the value using the given formatter.

impl Error for BuildError

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<BuildError> for ParseError

fn from(source: BuildError) -> Self

Converts to this type from the input type.

impl PartialEq for BuildError

fn eq(&self, other: &BuildError) -> 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 Eq for BuildError

impl StructuralPartialEq for BuildError