This content originally appeared on HackerNoon and was authored by hackernoon
In modern Go projects, it's too easy for accidental API changes or subtle documentation edits to sneak through pull requests or release processes unnoticed.
relimpact is a lightweight CLI tool that helps you understand what really changed between two Git refs — with clean, structured, human-friendly reports.
Use it in CI pipelines, release PRs, or locally before tagging new versions.
✨ Features
- 🔍 API Diff — Track breaking public API changes (structs, interfaces, functions, constants, variables).
- 📝 Docs Diff — Section-aware Markdown diff to highlight meaningful content changes.
- 🗂️ Other Files Diff — Group file changes by extension (.sh, .sql, .json, etc.) to surface migrations and auxiliary files.
- 🚀 Designed for Release PR reviews — Quickly see the real impact of changes.
- 🖋️ Markdown Reports — Ready to paste into GitHub Releases, Slack, or changelogs.
- ⚙️ Works in GitHub Actions, GitLab CI, or locally — Integrates easily.
- 🔒 No server required — Pure CLI tool.
🚀 Quickstart
Run on a GitHub PR:
relimpact --old=v1.0.0 --new=HEAD > release-impact.md
Example Output:
⚙️ GitHub Action Integration
name: Release Impact on PR
on:
pull_request:
branches: [ master ]
types: [ opened, synchronize, reopened ]
jobs:
release-impact:
name: Generate Release Impact Report
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v4
with:
fetch-depth: 0
- name: Determine previous tag
id: prevtag
run: |
git fetch --tags
TAG_LIST=$(git tag --sort=-version:refname)
PREV_TAG=$(echo "$TAG_LIST" | head -n2 | tail -n1)
echo "Previous tag: $PREV_TAG"
# Fallback to first tag if no previous
if [ -z "$PREV_TAG" ]; then
PREV_TAG=$(echo "$TAG_LIST" | head -n1)
echo "Fallback to first tag: $PREV_TAG"
fi
echo "prev_tag=$PREV_TAG" >> $GITHUB_OUTPUT
- name: Determine new ref
id: newref
run: |
if [ "${{ github.event_name }}" = "pull_request" ]; then
echo "new_ref=${{ github.event.pull_request.head.sha }}" >> $GITHUB_OUTPUT
else
echo "new_ref=HEAD" >> $GITHUB_OUTPUT
fi
- uses: hashmap-kz/relimpact-action@main
with:
old-ref: ${{ steps.prevtag.outputs.prev_tag }}
new-ref: ${{ steps.newref.outputs.new_ref }}
output: release-impact.md
- name: Upload Release Impact Report
uses: actions/upload-artifact@v4
with:
name: release-impact-${{ github.run_id }}-${{ github.run_attempt }}
path: release-impact.md
📦 Installation
Homebrew
brew tap hashmap-kz/homebrew-tap
brew install relimpact
Manual Download
🧠 How It Works
1️⃣ Go Source API Changes
- Uses Go type system & AST parsing:
- Detects breaking changes: method signatures, removed fields, new/removed types, etc.
- Ignores formatting & comment noise.
- Based on
golang.org/x/tools/go/packages.
2️⃣ Markdown Docs Changes
- Section-aware diff of
.mdfiles: - Headings added/removed.
- Links and images changes.
- Section word count diffs.
- Based on
goldmarkparser.
3️⃣ Other Files Changes
- Groups changes by file type:
.sql,.sh,.json,.yaml,.conf, etc.- Uses
git diff --name-status.
Why Use It?
Most release PRs include:
✅ API changes \n ✅ Doc updates \n ✅ Migration scripts \n ✅ Other important config tweaks
But raw git diffis noisy and hard to review. \n relimpact gives you a release-ready summary, focusing on what's important.
📜 License
MIT License. See LICENSE.
👉 Try it today: https://github.com/hashmap-kz/relimpact
If you found this useful, leave a ⭐ on GitHub — it helps others discover the project!
Happy releasing 🚀
\
This content originally appeared on HackerNoon and was authored by hackernoon
hackernoon | Sciencx (2025-06-10T19:25:21+00:00) This Lightweight Tool Flags Breaking Changes Before You Ship. Retrieved from https://www.scien.cx/2025/06/10/this-lightweight-tool-flags-breaking-changes-before-you-ship/
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