Enum MetricsError 

#[non_exhaustive]
pub enum MetricsError {
    EmptyRoot,
    LanguageDisabled(LANG),
}

Error returned by the library’s metric-computation entry points.

Stability

The variant set is additive: new variants may be introduced in minor versions, so the enum is marked #[non_exhaustive]. Existing variants will not be removed without a major version bump. The std::error::Error and std::fmt::Display impls are part of the stable surface; the exact wording of the Display output is not.

Examples

The MetricsError::EmptyRoot variant is reserved for a future walker change (see its documentation). The MetricsError::LanguageDisabled variant is the one actually produced today: every dispatch entry point emits it when the caller selects a LANG whose per-language Cargo feature is not enabled in the current build (see #252). The example exercises the happy path and demonstrates the exhaustive-with-_ match shape that callers should adopt to stay forward-compatible with future variants.

use big_code_analysis::{analyze, MetricsError, MetricsOptions, Source, LANG};

let source = Source::new(LANG::Cpp, b"int a = 42;");
let result = analyze(source, MetricsOptions::default());

// Today this call succeeds; the match below documents the shape
// callers must adopt so adding a future variant is non-breaking.
assert!(result.is_ok());

match result {
    Ok(_space) => {}
    Err(MetricsError::EmptyRoot) => {
        // Reserved: walker produced no top-level FuncSpace.
    }
    Err(MetricsError::LanguageDisabled(_lang)) => {
        // The `LANG` variant the caller asked for has no grammar
        // crate compiled in for this build (per-language feature
        // disabled — see the `[features]` table in Cargo.toml).
    }
    // `MetricsError` is `#[non_exhaustive]`; new variants may be added.
    Err(_) => {}
}

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.

EmptyRoot

The walker produced no top-level FuncSpace.

Reserved — not produced today. metrics_with_options always pushes a synthetic top-level SpaceKind::Unit FuncSpace onto its state stack before walking the AST, so every parse — including empty input, whitespace-only input, and comment-only input — currently returns Ok(FuncSpace { kind: Unit, .. }). The variant is kept for a future walker change that lets the state stack legitimately drain to empty (e.g. an option that suppresses the synthetic root for sources with no parseable structure).

LanguageDisabled(LANG)

The requested LANG is not enabled in this build.

Produced by every dispatch entry point (crate::analyze, crate::Ast::parse, crate::Ast::from_tree_sitter, and crate::LANG::tree_sitter_language) when the caller selects a LANG variant whose per-language Cargo feature is not enabled in the current build — see the [features] table in the root Cargo.toml for the list. The default feature set (default = ["all-languages"]) keeps every grammar compiled in, matching the library’s historical behaviour; callers that opt into a narrower set with --no-default-features --features rust,… are the only ones that observe this variant.

Trait Implementations

impl Clone for MetricsError

fn clone(&self) -> MetricsError

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for MetricsError

impl Debug for MetricsError

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

Formats the value using the given formatter.

impl Display for MetricsError

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

Formats the value using the given formatter.

impl Eq for MetricsError

impl Error for MetricsError

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<MetricsError> for FromPathError

fn from(e: MetricsError) -> Self

Converts to this type from the input type.

impl PartialEq for MetricsError

fn eq(&self, other: &MetricsError) -> 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 StructuralPartialEq for MetricsError