# mozilla/grcov

Rust tool to collect and aggregate code coverage data for multiple source files

Repository: https://github.com/mozilla/grcov
Canonical: https://ross.abutalabs.com/products/grcov
Language: Rust
License: MPL-2.0
License Family: copyleft
Last push: 2026-06-02T23:34:09+00:00

## Health v2 (maintenance only)
Score: 84/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 85, release rhythm 73, longevity 100
- inputs: {"age_days": 3473, "days_push": 92, "days_rel": 183, "gap_med": 5.5, "n_releases_24m": 13}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1361, forks 171 (observed 2026-08-28T04:04:29.985634+00:00)

## What it is
grcov is a fast Rust-based CLI tool that collects and aggregates code coverage data from multiple source files. It processes .profraw and .gcda files from LLVM/Clang and GCC, plus lcov, Go, and JaCoCo coverage formats, and outputs reports as HTML, lcov, Coveralls, Cobertura, and more.

## Use cases
- generate code coverage reports for a Rust project
- aggregate C/C++ gcda coverage files into an HTML report
- upload coverage to Coveralls from CI
- merge coverage from multiple test runs and languages
- produce lcov or cobertura output for a coverage service
- collect JavaScript and Java coverage alongside native code coverage

## When to choose
- you need a fast, single-binary coverage aggregator across C/C++, Rust, Go, Java, or JS
- you want CI-friendly outputs like Coveralls, lcov, or Cobertura
- you're working in a Mozilla/Firefox-style multi-language build pipeline

## When to avoid
- you only need simple line coverage for a pure-Python or pure-Ruby project where native tooling suffices
- you need IDE-integrated live coverage rather than report generation
- you require platforms beyond Linux, macOS, or Windows

## Facets
- artifact type: cli-tool
- maturity: active
- function: testing, developer-tools, ci-cd
- domain: developer-tools, testing
- platform: windows, cli, rust
- tags: code-coverage, coverage-reporting, llvm, gcc, lcov, coveralls, cobertura, linux, macos

## Member repositories
- mozilla/grcov (main) score 84

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:04:29.985634+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T04:41:36.025141+00:00, confidence not recorded.
  - readme: https://github.com/mozilla/grcov (fetched 2026-08-28T04:04:29.985634+00:00, sha 0279785bd2db)
  - registry_crates: https://crates.io/api/v1/crates/grcov (fetched 2026-08-29T11:59:16.223285+00:00, sha e7ab86e14f4b)
- Data as of 2026-08-30T08:39:29.467469+00:00.