Enum Error 

pub enum Error {
    Io {
        path: PathBuf,
        source: Error,
    },
    Pragma {
        path: PathBuf,
        label: String,
        detail: String,
    },
    Drift {
        path: PathBuf,
        line: usize,
        expected: String,
        actual: String,
    },
    Unclassifiable {
        generator: &'static str,
        detail: String,
    },
    Manifest {
        path: PathBuf,
        detail: String,
    },
    Arm {
        origin: String,
        detail: String,
    },
    Parity(Box<ParityMismatch>),
}

Everything the generators can fail with.

Variants

Io

A file could not be read or written.

Fields

path: PathBuf

The path, relative to the repository root where possible.

source: Error

The underlying filesystem error.

Pragma

A page is missing one of its auto-generated pragmas, or carries it twice.

The generator writes only between the pragmas, so a page whose framing does not delimit a region has no place for the output and is an error rather than an opportunity to append one.

Fields

path: PathBuf

The page, relative to the repository root.

label: String

The pragma label the generator looked for.

detail: String

What was wrong.

Drift

A page on disk does not match what the generator would write.

This is --mode check’s only failure, and the message names the file, the first differing line and both versions of it.

Fields

path: PathBuf

The page, relative to the repository root.

line: usize

The 1-based line number of the first difference.

expected: String

The line the generator would write.

actual: String

The line that is on disk.

Unclassifiable

A generator could not determine the truth about its input.

The fail-closed variant: an unparsable manifest, an enum variant whose message the generator cannot read, a value it has no rule for. It never degrades to a placeholder.

Fields

generator: &'static str

Which generator refused.

detail: String

What it could not classify, and what to do about it.

Manifest

examples/parity.toml does not describe the examples that exist.

Every rejection of the grammar (docs/design/11-documentation-plan.md §17.5) lands here: a duplicate name, a file that is named but absent, a params-only entry missing its tolerance or reason, an unpaired entry with no reason, and — the rule that makes silent exclusion impossible — an example file that appears in no entry at all.

Fields

path: PathBuf

The manifest, relative to the repository root.

detail: String

What is wrong, and what to write instead.

Arm

One arm of a parity pair could not be run, or printed no parity block.

Kept separate from Error::Parity because the two mean different things: this is “the example did not produce a comparable answer”, which is a broken example (or a missing wheel), while a mismatch is two working examples that disagree.

Fields

origin: String

Which arm, spelled as the command that runs it.

detail: String

What went wrong, and what to do about it.

Parity(Box<ParityMismatch>)

Two parity blocks disagree on a field.

Boxed because it is by far the largest variant — seven owned strings — and an unboxed one makes every Result in this crate wide enough to trip clippy::result_large_err on functions that can never return it.

Implementations

impl Error

pub fn io(path: impl Into<PathBuf>, source: Error) -> Self

Wraps a filesystem error with the path it happened on.

pub fn unclassifiable( generator: &'static str, detail: impl Into<String>, ) -> Self

Reports an input a generator has no rule for.

pub fn manifest(path: impl Into<PathBuf>, detail: impl Into<String>) -> Self

Reports a manifest that does not describe the examples on disk.

pub fn arm(origin: impl Into<String>, detail: impl Into<String>) -> Self

Reports an arm that did not produce a comparable answer.

Trait Implementations

impl Debug for Error

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

Formats the value using the given formatter.

impl Display for Error

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

Formats the value using the given formatter.

impl Error for Error

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.