Enum GraphError 

#[non_exhaustive]
pub enum GraphError {
    #[non_exhaustive]
    Cycle {
        tasks: Vec<String>,
    },
    #[non_exhaustive]
    AmbiguousOrder {
        a: String,
        b: String,
        resource: String,
    },
    #[non_exhaustive]
    UnknownDependency {
        task: String,
        missing: String,
    },
    #[non_exhaustive]
    DuplicateTask {
        task: String,
    },
    #[non_exhaustive]
    TooLarge {
        tasks: usize,
        reason: &'static str,
    },
    #[non_exhaustive]
    MissingResource {
        task: String,
        resource: String,
    },
    #[non_exhaustive]
    UndeclaredAccess {
        task: String,
        resource: String,
        access: &'static str,
    },
    #[non_exhaustive]
    BorrowConflict {
        task: String,
        resource: String,
    },
    #[non_exhaustive]
    TaskFailed {
        task: String,
        message: String,
    },
    #[non_exhaustive]
    TaskPanicked {
        task: String,
        message: String,
    },
    Job(JobError),
}

Errors of building and running the graph.

Build errors (FrameGraphBuilder::build) are returned before the first frame and name the tasks; frame errors (FrameGraph::run) are the first error of the task with the lowest registration index, so with identical failures the result does not depend on thread scheduling.

The enum and its variants are #[non_exhaustive]: match with .. and a wildcard arm. Inside a task, ? on a GraphError (for example from TaskContext::read) passes it through unchanged.

use pragma_graph::{FrameGraph, GraphError};

struct Bodies;

let mut g = FrameGraph::builder();
g.task("physics", |t| t.writes::<Bodies>(), |_| ());
g.task("debug draw", |t| t.reads::<Bodies>(), |_| ());
match g.build() {
    Err(GraphError::AmbiguousOrder { a, b, .. }) => {
        // Fix: `.after("physics")` on "debug draw", or `FrameGraph::builder().ordered()`.
        assert_eq!((a.as_str(), b.as_str()), ("physics", "debug draw"));
    }
    other => panic!("unexpected {other:?}"),
}

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

#[non_exhaustive]

Cycle

The graph has a dependency cycle.

Fields

Non-exhaustive enum variants could have additional fields added in future. Therefore, non-exhaustive enum variants cannot be constructed in external crates and cannot be matched against.

tasks: Vec<String>

The tasks forming the cycle, in edge order (an edge leads from the last one to the first).

#[non_exhaustive]

AmbiguousOrder

Two tasks write (or write/read) the same resource without an explicit order.

Fields

Non-exhaustive enum variants could have additional fields added in future. Therefore, non-exhaustive enum variants cannot be constructed in external crates and cannot be matched against.

a: String

The first task (in registration order).

b: String

The second task.

resource: String

The conflicting resource.

#[non_exhaustive]

UnknownDependency

A dependency on a task that is not registered.

Fields

Non-exhaustive enum variants could have additional fields added in future. Therefore, non-exhaustive enum variants cannot be constructed in external crates and cannot be matched against.

task: String

The task with the dependency.

missing: String

The missing task.

#[non_exhaustive]

DuplicateTask

A task name is registered twice.

Fields

Non-exhaustive enum variants could have additional fields added in future. Therefore, non-exhaustive enum variants cannot be constructed in external crates and cannot be matched against.

task: String

The repeated name.

#[non_exhaustive]

TooLarge

The graph does not fit the build limits (MAX_TASKS, MAX_EDGES) or memory for the plan could not be allocated; returned instead of an abort on a large input.

Fields

Non-exhaustive enum variants could have additional fields added in future. Therefore, non-exhaustive enum variants cannot be constructed in external crates and cannot be matched against.

tasks: usize

Number of tasks in the description.

reason: &'static str

Which limit was exceeded (or out of memory).

#[non_exhaustive]

MissingResource

A task declared a resource that is not in Resources.

Fields

Non-exhaustive enum variants could have additional fields added in future. Therefore, non-exhaustive enum variants cannot be constructed in external crates and cannot be matched against.

task: String

The first task that declared the resource.

resource: String

The resource.

#[non_exhaustive]

UndeclaredAccess

A task accessed a resource without declaring that access.

Fields

Non-exhaustive enum variants could have additional fields added in future. Therefore, non-exhaustive enum variants cannot be constructed in external crates and cannot be matched against.

task: String

The task.

resource: String

The resource.

access: &'static str

"read" or "write".

#[non_exhaustive]

BorrowConflict

The resource is already borrowed (for example a task took it for writing twice).

Fields

Non-exhaustive enum variants could have additional fields added in future. Therefore, non-exhaustive enum variants cannot be constructed in external crates and cannot be matched against.

task: String

The task.

resource: String

The resource.

#[non_exhaustive]

TaskFailed

A task returned an error.

Fields

Non-exhaustive enum variants could have additional fields added in future. Therefore, non-exhaustive enum variants cannot be constructed in external crates and cannot be matched against.

task: String

The task.

message: String

The error text.

#[non_exhaustive]

TaskPanicked

A task panicked; the panic was caught, and the dependent tasks of this frame did not run.

Fields

Non-exhaustive enum variants could have additional fields added in future. Therefore, non-exhaustive enum variants cannot be constructed in external crates and cannot be matched against.

task: String

The task.

message: String

The panic message, if it was a string.

Job(JobError)

A job pool error.

Trait Implementations

impl Clone for GraphError

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for GraphError

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

Formats the value using the given formatter.

impl Display for GraphError

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

Formats the value using the given formatter.

impl Eq for GraphError

impl Error for GraphError

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<JobError> for GraphError

fn from(source: JobError) -> Self

Converts to this type from the input type.

impl PartialEq for GraphError

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for GraphError