Crate fallow_cov_protocol 

Versioned envelope types shared between the public fallow CLI and the closed-source fallow-cov production-coverage sidecar.

The public CLI builds a Request from its static analysis output, spawns the sidecar, writes the request to stdin, and reads a Response from stdout. Both sides depend on this crate to guarantee contract alignment.

Versioning

The top-level protocol_version field is a full semver string. Major bumps indicate breaking changes; consumers MUST reject mismatched majors. Minor bumps add optional fields; consumers MUST forward-accept unknown fields and SHOULD map unknown enum variants to Feature::Unknown, ReportVerdict::Unknown, or Verdict::Unknown rather than erroring.

0.2 overview

This is the first production-shaped contract. The top-level ReportVerdict (previously Verdict) is unchanged in meaning but was renamed to avoid colliding with per-finding Verdict. Each Finding and HotPath now carries a deterministic finding_id / hot_path_id hash, a full Evidence block, and — for findings — a per-function verdict and nullable invocation count. Confidence gained VeryHigh and None variants to match the decision table in .internal/spec-production-coverage.md.

StaticFunction::static_used and StaticFunction::test_covered are intentionally required (no #[serde(default)]) — a silent default would hide every safe_to_delete finding, so 0.1-shape requests must fail deserialization instead of parsing into a wrong answer.

Structs

Action

Machine-readable next-step hint for AI agents.

CaptureQuality

Capture-quality telemetry surfaced alongside the aggregate summary.

DiagnosticMessage

Error / warning surfaced by the sidecar.

Evidence

Supporting evidence for a Finding. Mirrors the rows of the decision table in .internal/spec-production-coverage.md so the CLI can render the “why” behind each verdict without re-deriving it.

Finding

A per-function finding combining static analysis and runtime coverage.

HotPath

A function the sidecar identified as a hot path in the current dump.

License

The license material the sidecar should validate.

Options

Runtime knobs. All fields are optional so new options can be added without a breaking change.

Request

Sent by the public CLI to the sidecar via stdin.

Response

Emitted by the sidecar to stdout.

StaticFile

Static analysis results for a single source file.

StaticFindings

Static analysis output the public CLI already produced.

StaticFunction

Static analysis results for a single function within a StaticFile.

Summary

Aggregate statistics describing the observed coverage dump.

Enums

Confidence

Confidence the sidecar attaches to a Finding::verdict.

CoverageSource

A single coverage artifact on disk.

Feature

Feature flags present in the license JWT’s features claim.

ReportVerdict

Top-level report verdict (was Verdict in 0.1). Summarises the overall state of the run; per-finding verdicts live on Finding::verdict. Unknown variants are forward-mapped to ReportVerdict::Unknown.

Verdict

Per-finding verdict. Replaces the 0.1 CallState enum.

Watermark

What to render in the human output when the license is in the grace window.

Constants

PROTOCOL_VERSION

Current protocol version. Bumped per the semver rules above.

Functions

finding_id

Compute the deterministic Finding::id for a production-coverage finding.

hot_path_id

Compute the deterministic HotPath::id for a hot-path finding. Uses the same canonical order as finding_id with kind "hot", emitting fallow:hot:<hash>.