Single-source the version

The approach

ModuLearn already builds with hatchling (see [build-system] in pyproject.toml), and hatchling can read the version straight out of a Python attribute. So keep __version__ in modulearn/__init__.py as the one source — runtime code and modulearn --version already import it — and have pyproject.toml declare the version dynamic, pointing back at that attribute.

1. Source of truth: modulearn/__init__.py → __version__.
2. Derived at build: pyproject.toml reads it via [tool.hatch.version].

Steps

1. Make pyproject's version dynamic
   pyproject.toml — the [project] table

   Delete the hard-coded version = "0.2.0" line and declare it dynamic instead.

   [project]
   name = "modulearn"
   # version = "0.2.0"        <- remove this line
   dynamic = ["version"]
   ...

2. Point hatchling at __init__.py
   pyproject.toml — a new table near the build config

   Tell the hatchling version hook which attribute to read.

   [tool.hatch.version]
   path = "modulearn/__init__.py"

   No pattern needed. Hatchling looks for a __version__ = "..." assignment by default, which is exactly what __init__.py already has.
3. Leave __init__.py as the single source
   modulearn/__init__.py — unchanged

   Nothing to edit here — __version__ = "0.2.0" stays put. From now on this is the only line you bump to cut a release.

4. Verify build and runtime agree

   Build a wheel and confirm its version is read from the Python attribute, and that the runtime reports the same string.

   pip install -e ".[dev]"                    # ensure hatchling + build are present
   python -m build 2>&1 | grep -i modulearn    # wheel name shows the version
   # e.g. Successfully built modulearn-0.2.0.tar.gz and modulearn-0.2.0-py3-none-any.whl
   modulearn --version                        # expect: modulearn 0.2.0
   python -c "import modulearn; print(modulearn.__version__)"   # 0.2.0

   The real test is a bump. Temporarily change __version__ to "0.2.1", rebuild, and confirm the wheel name follows — then revert. If the wheel tracks the edit with no other change, the two sources are truly one.
5. Commit

   git add pyproject.toml
   git commit -m "Single-source the version from modulearn/__init__.py"
   git push
   gh run list --branch main --limit 1   # expect: success

6. Mark it shipped on the roadmap

   Add done:true, to the {area:"hygiene", … title:"Single-source the version"} item in docs/roadmap.html.

Worth knowing