Derive the version from git tags (hatch-vcs)

.github/workflows/ci.yml

@@ -10,6 +10,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0   # hatch-vcs derives the version from git tags
 
       - uses: actions/setup-python@v5
         with:
@@ -30,11 +32,14 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0   # hatch-vcs derives the version from git tags
       - name: Smoke test on glibc 2.34
         run: |
           docker run --rm -v "$PWD":/w -w /w \
             quay.io/pypa/manylinux_2_34_x86_64 bash -c '
               PY=/opt/python/cp311-cp311/bin/python
+              git config --global --add safe.directory /w &&
               "$PY" -m pip install -e . pytest &&
               "$PY" scripts/vendor_binaries.py --only gomc-rest-linux-amd64 &&
               "$PY" -m pytest -v

.github/workflows/release.yml

@@ -35,20 +35,14 @@ jobs:
             plat: manylinux2014_aarch64
     steps:
       - uses: actions/checkout@v4
+        with:
+          # hatch-vcs derives the version from git tags
+          fetch-depth: 0
 
       - uses: actions/setup-python@v5
         with:
           python-version: "3.11"
 
-      - name: Check tag matches project version
-        if: github.ref_type == 'tag'
-        shell: bash
-        run: |
-          tag="${GITHUB_REF_NAME#v}"
-          proj=$(python -c "import tomllib,pathlib; print(tomllib.loads(pathlib.Path('pyproject.toml').read_bytes().decode())['project']['version'])")
-          echo "tag=$tag project.version=$proj"
-          test "$tag" = "$proj" || { echo "::error::tag $GITHUB_REF_NAME does not match project.version $proj"; exit 1; }
-
       - name: Install build tooling
         run: python -m pip install --upgrade build wheel
 
@@ -72,19 +66,13 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
 
       - uses: actions/setup-python@v5
         with:
           python-version: "3.11"
 
-      - name: Check tag matches project version
-        if: github.ref_type == 'tag'
-        shell: bash
-        run: |
-          tag="${GITHUB_REF_NAME#v}"
-          proj=$(python -c "import tomllib,pathlib; print(tomllib.loads(pathlib.Path('pyproject.toml').read_bytes().decode())['project']['version'])")
-          test "$tag" = "$proj" || { echo "::error::tag $GITHUB_REF_NAME does not match project.version $proj"; exit 1; }
-
       - name: Build sdist (no binary bundled)
         run: |
           python -m pip install --upgrade build

RELEASING.md

@@ -6,8 +6,8 @@ Maintainer notes. Users don't need anything here — see [README.md](README.md).
 
 Pushing a `v*` tag runs `.github/workflows/release.yml`:
 
-1. **Guard** — the tag must equal `project.version` in `pyproject.toml`,
-   or every job fails immediately.
+1. **Version** — derived from the tag itself by hatch-vcs
+   (`dynamic = ["version"]`); there is no version string to keep in sync.
 2. **Build wheels** (one per platform, each bundling only its matching
    server binary, downloaded and SHA-256-verified at build time):
    - `win_amd64` — `gomc-rest.exe`
@@ -25,15 +25,17 @@ Pushing a `v*` tag runs `.github/workflows/release.yml`:
 
 ## Cutting a release
 
-1. Bump the package version in **both** places (they must match the tag):
-   - `pyproject.toml` → `project.version`
-   - `src/gomc_rest/__init__.py` → `__version__`
-2. Merge to `main`, then tag that exact version:
+Tag `main` and push — that's all. The version comes from the tag
+(hatch-vcs), and `__version__` reads the installed package metadata, so
+there is nothing to bump anywhere.
 
-   ```bash
-   git tag v0.2.0
-   git push origin v0.2.0
-   ```
+```bash
+git tag v0.2.0
+git push origin v0.2.0
+```
+
+Untagged builds get a dev version like `0.1.3.dev2+g1234abc` — handy for
+telling local builds apart from releases.
 
 If publish fails transiently, re-run the failed jobs for that tag's run
 from the GitHub Actions UI — PyPI skips files it already has, and the

pyproject.toml

@@ -1,10 +1,12 @@
 [build-system]
-requires = ["hatchling"]
+requires = ["hatchling", "hatch-vcs"]
 build-backend = "hatchling.build"
 
 [project]
 name = "gomc-rest"
-version = "0.1.2"
+# The version comes from the git tag (hatch-vcs); releasing is just pushing
+# a v* tag — no manual bump anywhere.
+dynamic = ["version"]
 description = "Talk to Mitsubishi PLCs from Python over the MC protocol via a bundled, auto-launched gomc-rest server — with optional REST API exposure."
 readme = "README.md"
 requires-python = ">=3.10"
@@ -26,6 +28,9 @@ Homepage = "https://github.com/Moge800/gomc_rest_python"
 "Upstream server" = "https://github.com/Moge800/gomc-rest"
 "HTTP client" = "https://github.com/Moge800/gomc_rest_client"
 
+[tool.hatch.version]
+source = "vcs"
+
 [tool.hatch.build.targets.wheel]
 packages = ["src/gomc_rest"]
 # The platform-specific server binaries under gomc_rest/binaries/ are vendored

src/gomc_rest/__init__.py

@@ -29,9 +29,14 @@
     PLCClient,
 )
 
+from importlib.metadata import PackageNotFoundError, version as _pkg_version
+
 from ._server import Server
 
-__version__ = "0.1.2"
+try:
+    __version__ = _pkg_version("gomc-rest")
+except PackageNotFoundError:  # running from a source tree without install
+    __version__ = "0.0.0.dev0"
 
 
 def launch(