coverage.yml

# SPDX-License-Identifier: MPL-2.0
# Copyright (c) 2026 Jonathan D.A. Jewell (hyperpolymath) <j.d.a.jewell@open.ac.uk>
#
# coverage.yml — Code coverage reporting via cargo-tarpaulin.
# Generates coverage report and uploads to Codecov.
name: Coverage

on:
  pull_request:
    branches: ['**']
  push:
    branches: [main]

permissions:
  contents: read

jobs:
  coverage:
    name: Code coverage
    # No `if: hashFiles('Cargo.toml') != ''` guard — `hashFiles()` is invalid in
    # a job-level `if:` and startup-fails the whole workflow (see rust-ci.yml).
    # This repo always has a Cargo workspace.
    runs-on: ubuntu-latest
    timeout-minutes: 45

    steps:
      - name: Checkout repository
        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v4

      - name: Install Rust toolchain
        uses: dtolnay/rust-toolchain@4be9e76fd7c4901c61fb841f559994984270fce7 # stable

      - name: Cache cargo registry and build
        uses: Swatinem/rust-cache@c19371144df3bb44fab255c43d04cbc2ab54d1c4 # v2

      - name: Install cargo-tarpaulin
        run: cargo install cargo-tarpaulin

      - name: Generate coverage report
        run: |
          cargo tarpaulin \
            -p jtv-core \
            --out xml \
            --out html \
            --output-dir coverage/ \
            --skip-clean \
            --timeout 120

      - name: Upload to Codecov
        uses: codecov/codecov-action@fb8b3582c8e4def4969c97caa2f19720cb33a72f # v5
        with:
          files: coverage/cobertura.xml
          fail_ci_if_error: false

      - name: Write summary
        if: always()
        run: |
          echo "## Code Coverage Report" >> "$GITHUB_STEP_SUMMARY"
          echo "" >> "$GITHUB_STEP_SUMMARY"
          if [ -f coverage/cobertura.xml ]; then
            LINE_RATE=$(grep -oP 'line-rate="\K[^"]+' coverage/cobertura.xml | head -1)
            PERCENT=$(echo "$LINE_RATE * 100" | bc -l 2>/dev/null | head -c 5 || echo "$LINE_RATE")
            echo "Line coverage: **${PERCENT}%**" >> "$GITHUB_STEP_SUMMARY"
          else
            echo "Coverage report not generated." >> "$GITHUB_STEP_SUMMARY"
          fi

      - name: Upload HTML report as artifact
        if: always()
        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
        with:
          name: coverage-report
          path: coverage/
          retention-days: 30