The One That Got Away

Fix: Baseline retrieval pages back through default-branch runs

The action found the baseline by inspecting only the single most recent successful default-branch run for the lcov-baseline artifact. But a successful run doesn't guarantee a baseline — the coverage job is often conditional (path filters, matrix skips, flaky reruns), so the latest run can complete without one while an older run still holds a perfectly valid baseline.

When that happened, the action silently fell back to summary-only mode: ratcheting wasn't enforced (passed=true hardcoded) and no PR comparison comment was posted. Coverage could regress behind a green check, intermittently, depending only on what the most recent default-branch commit happened to touch.

Retrieval now pages back through recent successful default-branch runs (newest first) and uses the first that still holds a non-expired lcov-baseline[-<label>] artifact, only falling back to summary-only mode when none of the inspected runs has one. Pagination follows the Link: rel="next" header (per_page=100, 50-page cap). (#15)

Also

• Hardened the per-run artifact query so a transient failure (or malformed response) for one run skips that run and keeps paging, instead of aborting the whole search.
• mktemp calls now use a ${TMPDIR:-/tmp}/… template, matching the rest of the codebase (portable; the previous bare mktemp -d ignored $TMPDIR on macOS).

No workflow changes needed. Existing setups pick up the fix automatically.

One Comment to Rule Them All

New: Consolidated PR comments

Multiple coverage labels now share a single PR comment instead of posting separate comments per label. Each label occupies its own section within the comment, independently updated on each run.

Sections are sorted alphabetically (unlabeled runs appear first as "default"). A read-modify-write cycle with retry handles concurrent updates from parallel jobs. (#14)

Migration

Old-format per-label comments are automatically deleted on the first run after upgrading. No manual cleanup needed.

Single-invocation users without coverage-label are unaffected — the comment format changes internally but the visible content is identical.

Label Me Impressed

Breaking changes

The new coverage-label input namespaces PR comments and baseline artifacts per label (e.g., lcov-baseline-go instead of lcov-baseline). If you add a coverage-label to an existing invocation, it won't find the previous unlabeled baseline artifact — a fresh baseline will be created on the next push to your default branch. Any open PRs should be rebased or updated after that merge to pick up the new baseline.

Single-invocation users who don't use coverage-label are unaffected.

New: Multi-language coverage labels

The coverage-label input lets you run the action multiple times in the same workflow without PR comment or artifact collisions. Each label gets its own namespaced comment and baseline artifact.

- uses: pento/lcov-coverage-check@v3
  with:
    lcov-file: coverage/go.lcov
    coverage-label: go
    github-token: ${{ secrets.GITHUB_TOKEN }}

- uses: pento/lcov-coverage-check@v3
  with:
    lcov-file: coverage/frontend.lcov
    coverage-label: frontend
    github-token: ${{ secrets.GITHUB_TOKEN }}

Smart collision detection warns when labels are inconsistently applied across runs. (#8)

Fix: PR comment pagination

The action now paginates the PR comment lookup, fixing duplicate comment posting on PRs with more than 100 comments. (#10)

Fix: Temp file cleanup

Temporary files created during LCOV filtering are now properly cleaned up. (#13)

Internal: Module restructuring

Split large script files into smaller, focused library modules under scripts/lib/. No user-facing changes. (#11)

These Paths Were Made for Walking

New: Multiple path prefixes

The path input now accepts multiple path prefixes, one per line. Projects with source code in multiple directories can enforce coverage checks across all of them.

- uses: pento/lcov-coverage-check@v2
  with:
    path: |
      lib/
      src/
    github-token: ${{ secrets.GITHUB_TOKEN }}

Previously, path accepted a single prefix. Existing single-path usage is unchanged. (#7)

Still Waters Run Shallow

Fix: New/modified file detection in shallow clones

actions/checkout defaults to fetch-depth: 1, which means only the merge commit is available locally. The action's git diff calls used three-dot syntax (A...B), which requires merge-base computation and connected history between commits — neither of which exist in a shallow clone. The error was silently swallowed, causing the action to report "No new files detected" and "No modified files detected" even when the PR had changed files.

Three changes:

• Auto-fetch refs: Before running git diff, the action now fetches the base and head refs with git fetch --depth=1. No workflow changes needed.
• Two-ref diff syntax: Switched from A...B (merge-base) to A B (direct tree comparison), which only needs the two commits to be present.
• Warnings on failure: If git diff still fails (e.g., no remote access), a ::warning:: annotation is emitted instead of silently returning zero files. (#6)

Ignorance is Bliss

New: Ignore patterns

A new ignore-patterns input lets you exclude files from all coverage checks. Specify one glob pattern per line — matched files are filtered out of LCOV data before parsing, skipped in new-file minimum coverage checks, and skipped in changed-file ratchet checks.

- uses: pento/lcov-coverage-check@v2
  with:
    ignore-patterns: |
      **/generated/**
      **/*.g.dart

Fix: Actionable error for missing actions:read permission

When GITHUB_TOKEN lacks actions: read permission, the action now emits a clear notice naming the missing permission instead of silently falling back to summary-only mode with a generic error. (#4)

Chore: Updated dependencies

• actions/upload-artifact upgraded from v4 to v7
• actions/download-artifact upgraded to latest

Smarter, Better, Faster, Stronger

What's New

Language-agnostic file type support

The action no longer hardcodes .dart as the only supported file extension. File extensions are now derived automatically from the SF: lines in your LCOV data, so it works out of the box with any language that produces LCOV coverage — Go, Python, TypeScript, C/C++, Ruby, and more. No configuration needed; existing Dart projects behave identically.

Automatic baseline management

The action now manages baseline coverage artifacts end-to-end. Provide a github-token and:

• On pushes to the default branch: the current LCOV file is uploaded as an lcov-baseline artifact
• On pull requests: the baseline is auto-retrieved from the latest successful default-branch run, and git refs are auto-detected from the PR event payload

This replaces the previous manual lcov-base, base-ref, and head-ref inputs — users just provide github-token and the action handles the rest.

Bug fixes

• Fix PR comment posting: reads the PR number from GITHUB_EVENT_PATH payload instead of the non-existent GITHUB_EVENT_NUMBER env var (#1)
• GHES compatibility: all API calls now use GITHUB_API_URL instead of hardcoded api.github.com (#2)

Breaking changes

• The lcov-base, base-ref, head-ref, and new-file-path-prefix inputs have been removed in favor of automatic management via
  github-token
• new-file-path-prefix is replaced by path

Testing

Test suite expanded from 3 to 25 tests covering baseline retrieval, PR comments, GHES compatibility, and multi-language extension support.

Hello, World!

LCOV Coverage Check

A composite GitHub Action that parses LCOV coverage files and enforces coverage standards on pull requests.

Features

• Coverage summary — Reports overall line coverage from any LCOV file.
• Baseline comparison — Compare current coverage against a baseline LCOV file to catch regressions.
• New file thresholds — Enforce a minimum coverage percentage on newly added files (configurable path prefix and threshold).
• Per-file regression guard — Optionally fail when modified files lose coverage vs. the baseline.
• PR comments — Post a formatted coverage summary directly on the pull request (requires github-token).
• Outputs — Exposes overall-coverage, baseline-coverage, and passed for downstream steps.

Usage

- uses: pento/lcov-coverage-check@v1
  with:
    lcov-file: coverage/lcov.info
    lcov-base: coverage/lcov-base.info
    base-ref: ${{ github.event.pull_request.base.sha }}
    github-token: ${{ secrets.GITHUB_TOKEN }}