Module vcs 

Available on crate feature vcs-git only.

Change-history (VCS) metrics derived from version-control history: churn, commit frequency, author count / ownership dilution, bug- and security-fix history, and an ordinal composite risk score. See vcs::build_history_index.

Enable with the vcs Cargo feature (the umbrella over the current vcs-git backend, which is what the availability badge names). Change-history (VCS) metrics: per-file signals derived from version control history rather than the AST.

This is the project’s first metric family that is language-agnostic and not AST-derived (issue #328). It surfaces files most likely to harbour bugs or vulnerabilities using the signals the empirical literature most consistently backs — recent churn, commit frequency, author count and ownership dilution, bug- and security-fix history — combined into an ordinal risk_score.

Layout

The generic surface (error, options, stats, identity, classify, score, hotspot, jit, and build_history_index) carries no backend reference, so a future backend (Mercurial, Jujutsu, …; issue #335) reuses it unchanged. Backend-specific code lives under the git module behind the vcs-git Cargo feature.

Two scoring granularities are offered: build_history_index ranks files at a ref (issue #328), while score_commit scores a single commit for just-in-time defect-induction risk (issue #331).

v1 deliberately omits a Backend trait: with a single backend it would be premature abstraction. build_history_index delegates to the one available backend; the trait is extracted when a second backend lands.

Re-exports

pub use bus_factor::BUS_FACTOR_SCHEMA_VERSION;

pub use bus_factor::BusFactor;

pub use bus_factor::DirectoryBusFactor;

pub use bus_factor::GroupBusFactor;

pub use bus_factor::VcsAggregate;

pub use cache::CACHE_SCHEMA_VERSION;

pub use cache::CacheConfig;

pub use error::Error;

pub use identity::AuthorHashKey;

pub use jit::JIT_SCHEMA_VERSION;

pub use jit::JIT_SCORE_VERSION;

pub use jit::JitCommit;

pub use jit::JitContributions;

pub use jit::JitDiffContributions;

pub use jit::JitDiffReport;

pub use jit::JitDiffusion;

pub use jit::JitExperience;

pub use jit::JitFeatures;

pub use jit::JitHistory;

pub use jit::JitPurpose;

pub use jit::JitReport;

pub use jit::JitSize;

pub use jit::JitSource;

pub use options::FileTypeScope;

pub use options::Options;

pub use options::RiskFormula;

pub use options::parse_window;

pub use stats::Stats;

pub use trend::TREND_SCHEMA_VERSION;

pub use trend::Trend;

pub use trend::TrendDelta;

pub use trend::TrendDeltas;

pub use git::BlameSession;

pub use git::LineSpan;

pub use git::PerFunctionBlame;

Modules

bus_factor

Directory- and repo-level bus factor (a.k.a. truck factor) over a change-history walk, via the Avelino Degree-of-Authorship (DoA) heuristic (issue #332).

cache

Persistent change-history cache, keyed by HEAD SHA and repo identity (issue #334).

classify

Commit-message classification: bug-fix, security-fix, and revert detection via curated keyword regexes.

entropy

Shannon-entropy machinery shared by the two process-entropy signals added in issue #330.

error

Error type for the change-history (VCS) metrics pipeline.

git

The vcs-git backend: a gix-powered history walk.

hotspot

Complexity × churn “hotspot” score (Tornhill; Nagappan & Ball).

identity

Canonical author identity and bot-author detection.

jit

Just-in-time (commit-level) defect-induction risk scoring (issue #331).

options

Configuration for a change-history walk.

score

Composite risk-score formulas.

stats

Per-file change-history statistics: the public Stats output and the internal Accumulator that the backend feeds during a walk.

trend

Historical metric trend: the change-history (VCS) metrics computed at several points in time, so a consumer can see whether a file’s risk is improving or degrading rather than only its risk now (issue #333).

Structs

HistoryIndex

The result of one history walk: per-file Stats keyed by repository-relative path, plus walk-level metadata.

Functions

build_history_index

Walk the change history rooted at root and build a per-file HistoryIndex.

build_history_index_cached

Like build_history_index, but reuse and update the persistent change-history cache per config (issue #334).

build_trend

Sample the change-history metrics at points evenly-spaced moments across span_secs, ending at options.as_of (or wall-clock now), building a trend::Trend time series (issue #333).

parse_timestamp

Parse an --as-of timestamp into Unix seconds.

rank_by_risk

Rank entries by descending risk score, breaking ties on the file path (ascending), then truncate to the top top (0 = keep all).

score_commit

Score a single commit for just-in-time defect-induction risk (issue #331).

score_diff

Score an arbitrary unified diff for just-in-time defect-induction risk (issue #580).

workdir_root

Discover the working-tree root of the repository containing path.