Enum QueryError 

pub enum QueryError {
    Suspend,
    Cycle {
        path: Vec<String>,
    },
    Cancelled,
    MissingDependency {
        description: String,
    },
}

System-level query errors.

These are distinct from user domain errors, which should be wrapped in Query::Output (e.g., type Output = Result<T, MyError>).

Variants

Suspend

Query is waiting for async loading to complete.

This is returned when a dependency is still loading via a background task. Use runtime.query_async() to wait for loading to complete, or handle explicitly in your query logic.

Cycle

Dependency cycle detected.

The query graph contains a cycle, which would cause infinite recursion. The path contains a debug representation of the cycle.

Fields

path: Vec<String>

Debug representation of the queries forming the cycle.

Cancelled

Query execution was cancelled.

MissingDependency

A required dependency is missing.

Fields

description: String

Description of the missing dependency.

Trait Implementations

impl Clone for QueryError

fn clone(&self) -> QueryError

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for QueryError

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

Formats the value using the given formatter.

impl Display for QueryError

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

Formats the value using the given formatter.

impl Error for QueryError

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.