Covdir Report Action

A GitHub Action for generating simple code coverage reports from grcov-generated covdir files.

This action downloads grcov automatically and uses your project's LLVM tools (from rustup component add llvm-tools) to process coverage data.

Quick Start

The simplest way to use this action is with the bundled grcov (enabled by default):

on:
  pull_request:
  push:
    branches:
      - main

name: Rust Coverage

jobs:
  coverage:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v6
      - uses: dtolnay/rust-toolchain@stable
        with:
          components: llvm-tools
      - name: Test
        run: cargo test
        env:
          RUSTFLAGS: '-Cinstrument-coverage'
          LLVM_PROFILE_FILE: 'target/coverage/%p-%m.profraw'
      - name: Generate coverage report
        uses: ecliptical/covdir-report-action@v0.3
        with:
          summary: 'true'

Usage with Pre-generated covdir.json

If you prefer to run grcov yourself (for more control over its options), you can disable the built-in grcov integration and pass a pre-generated covdir.json file:

- uses: ecliptical/covdir-report-action@v0.3
  with:
    skip_grcov: 'true'
    file: ./target/covdir.json
    summary: 'true'

Inputs

Report Inputs

ID	Description	Required	Default
file	Path to covdir.json file	no	./target/covdir.json
summary	Write report to step summary if true	no	false
out	Write report to the given file	no
title	Report title	no	Line coverage

Bundled grcov Inputs

These inputs control the bundled grcov, which is enabled by default.

ID	Description	Required	Default
skip_grcov	Skip bundled grcov and use a pre-generated covdir.json file	no	false
coverage_path	Path to coverage data	no	./target/coverage
source_dir	Source directory for grcov (-s flag)	no	.
binary_path	Binary path for grcov (--binary-path flag)	no	./target/debug
keep_only	Keep only files matching pattern (--keep-only flag)	no	src/**
excl_start	Exclude start pattern (--excl-start flag)	no	^mod\s+tests?\s*\{$
branch	Include branch coverage (--branch flag)	no	true
grcov_args	Additional arguments to pass to grcov	no
version	Version of the action binaries to use	no	0.3.0
grcov_version	Version of grcov to use	no	0.10.5

Outputs

ID	Description
lines_covered	Number of lines covered
lines_missed	Number of lines missed
lines_total	Total number of lines
coverage_percent	Percentage of lines covered

Example

An example workflow that runs unit tests with coverage, generates a simple markdown report, outputs it as the job summary and posts it as a PR comment:

on:
  pull_request:
  push:
    branches:
      - main

name: Rust Coverage

jobs:
  coverage:
    runs-on: ubuntu-latest
    steps:
      - name: Check out the source code
        uses: actions/checkout@v6
      - name: Install Rust
        uses: dtolnay/rust-toolchain@stable
        with:
          components: llvm-tools
      - name: Run unit tests
        run: cargo test
        env:
          RUSTFLAGS: '-Cinstrument-coverage'
          LLVM_PROFILE_FILE: 'target/coverage/%p-%m.profraw'
      - name: Generate coverage report
        uses: ecliptical/covdir-report-action@v0.3
        with:
          summary: 'true'
          out: ./target/coverage.md
      - name: Add coverage comment to the pull request
        uses: marocchino/sticky-pull-request-comment@v2
        if: github.event_name == 'pull_request'
        with:
          hide_and_recreate: true
          hide_classify: "OUTDATED"
          path: ./target/coverage.md

Third-Party Software

This action downloads and uses grcov, a code coverage tool by Mozilla, which is licensed under the Mozilla Public License 2.0 (MPL-2.0). The grcov source code is available at https://github.com/mozilla/grcov.