ci: add MIT license, CI, and tag-driven release workflow

.github/workflows/ci.yml

@@ -0,0 +1,66 @@
+name: ci
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
+
+      # gofmt exits 0 even when it reformats, so check for named files instead.
+      - name: gofmt
+        run: |
+          unformatted="$(gofmt -l .)"
+          if [ -n "$unformatted" ]; then
+            echo "not gofmt'd:"
+            echo "$unformatted"
+            exit 1
+          fi
+
+      - name: vet
+        run: go vet ./...
+
+      - name: test
+        run: go test -race ./...
+
+      # This repo's whole pitch is zero third-party dependencies. Fail loudly
+      # if a require block ever appears rather than letting it in unnoticed.
+      - name: no third-party dependencies
+        run: |
+          if go list -m all | tail -n +2 | grep .; then
+            echo "third-party dependencies found; this project vendors none"
+            exit 1
+          fi
+
+      # Dogfood: the linter must accept the commits it is being built from.
+      #
+      # Two things make this fiddlier than it looks on pull_request events:
+      # checkout is shallow, so the base commit must be fetched before a range
+      # can resolve against it; and HEAD is the synthetic "Merge <sha> into
+      # <sha>" commit GitHub builds for the PR, which is not a conventional
+      # subject. Range endpoints are always included, so --no-merges does not
+      # drop it — lint up to the branch's real tip instead.
+      - name: lint own commits
+        env:
+          EVENT: ${{ github.event_name }}
+          BASE_SHA: ${{ github.event.pull_request.base.sha }}
+          HEAD_SHA: ${{ github.event.pull_request.head.sha }}
+        run: |
+          go build -o /tmp/commitlint .
+          if [ "$EVENT" = "pull_request" ]; then
+            git fetch --no-tags --depth=50 origin "$BASE_SHA" "$HEAD_SHA"
+            /tmp/commitlint lint --range "$BASE_SHA..$HEAD_SHA"
+          else
+            git log -1 --format=%B | /tmp/commitlint lint
+          fi

.github/workflows/release.yml

@@ -0,0 +1,74 @@
+name: release
+
+# Cutting a release is: git tag vX.Y.Z && git push origin vX.Y.Z
+on:
+  push:
+    tags: ["v*"]
+
+permissions:
+  contents: write # required to create the release and upload assets
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0 # full history so release notes can diff against the previous tag
+
+      - uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
+
+      - name: test
+        run: go test -race ./...
+
+      # A tag that ships a binary claiming a different version is worse than no
+      # release, so refuse to build one that disagrees with the tag.
+      - name: build release binaries
+        env:
+          VERSION: ${{ github.ref_name }}
+        run: |
+          mkdir -p dist
+          for target in \
+            linux/amd64 linux/arm64 \
+            darwin/amd64 darwin/arm64 \
+            windows/amd64; do
+            os="${target%/*}"; arch="${target#*/}"
+            name="commitlint_${VERSION}_${os}_${arch}"
+            out="dist/${name}/commitlint"
+            [ "$os" = "windows" ] && out="${out}.exe"
+            mkdir -p "dist/${name}"
+            CGO_ENABLED=0 GOOS="$os" GOARCH="$arch" \
+              go build -trimpath -ldflags "-s -w -X main.version=${VERSION}" -o "$out" .
+            cp LICENSE README.md "dist/${name}/"
+            if [ "$os" = "windows" ]; then
+              (cd dist && zip -qr "${name}.zip" "${name}")
+            else
+              (cd dist && tar -czf "${name}.tar.gz" "${name}")
+            fi
+            rm -rf "dist/${name}"
+          done
+          (cd dist && sha256sum ./*.tar.gz ./*.zip > checksums.txt)
+          ls -la dist
+
+      - name: verify version stamp matches tag
+        env:
+          VERSION: ${{ github.ref_name }}
+        run: |
+          go build -ldflags "-X main.version=${VERSION}" -o /tmp/commitlint .
+          got="$(/tmp/commitlint version)"
+          if [ "$got" != "$VERSION" ]; then
+            echo "binary reports '$got' but tag is '$VERSION'"
+            exit 1
+          fi
+
+      - name: publish release
+        env:
+          GH_TOKEN: ${{ github.token }}
+          VERSION: ${{ github.ref_name }}
+        run: |
+          gh release create "$VERSION" \
+            --title "$VERSION" \
+            --generate-notes \
+            dist/*.tar.gz dist/*.zip dist/checksums.txt

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 DivergentCodes
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

@@ -124,9 +124,32 @@ exec commitlint lint --file "$1"
 
 ## Releases
 
-Versions are published as **GitHub tagged releases** with changelogs in the
-release notes (no committed changelog file). Pin a released version in CI:
+Versions are published as **GitHub tagged releases** with autogenerated
+changelogs in the release notes (no committed changelog file). Pin a released
+version in CI:
 
 ```sh
-go install github.com/DivergentCodes/commitlint@v1.0.0
+go install github.com/DivergentCodes/commitlint@v1.0.1
 ```
+
+Each release also carries prebuilt binaries for linux, darwin, and windows
+(amd64 and arm64, except windows) plus a `checksums.txt`, for environments
+without a Go toolchain:
+
+```sh
+curl -sSfL -O https://github.com/DivergentCodes/commitlint/releases/download/v1.0.1/commitlint_v1.0.1_linux_amd64.tar.gz
+tar -xzf commitlint_v1.0.1_linux_amd64.tar.gz
+./commitlint_v1.0.1_linux_amd64/commitlint version
+```
+
+Cutting a release is pushing a tag — `.github/workflows/release.yml` runs the
+tests, cross-compiles, verifies the binary reports the tagged version, and
+publishes:
+
+```sh
+git tag v1.0.1 && git push origin v1.0.1
+```
+
+## License
+
+[MIT](LICENSE)