Read __version__ from the package metadata

CHANGELOG.md

@@ -3,6 +3,13 @@
 All notable changes to this project are documented in this file and maintained manually. The
 format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 
+## [Unreleased]
+
+### Changed
+
+- `__version__` is read from the installed package metadata (`importlib.metadata`), not hardcoded,
+  so it can no longer disagree with `pyproject.toml` (a hardcoded one went stale in releases).
+
 ## [0.1.0] - 2026-10-05
 
 ### Added

docs/src/content/docs/development/publishing.md

@@ -13,9 +13,9 @@ Enable GitHub Pages once in the repository settings, with "GitHub Actions" as th
 
 ## Releases and PyPI
 
-Before merging a release to `main`, update the version in `pyproject.toml`,
-`src/app/__init__.py` and `CITATION.cff` (including its release date), and add the release notes
-to `CHANGELOG.md`. On every push to `main`, the `Release` workflow:
+Before merging a release to `main`, update the version in `pyproject.toml` and `CITATION.cff`
+(including its release date), and add the release notes to `CHANGELOG.md`. The package's
+`__version__` is read from the installed metadata, so it follows `pyproject.toml`. On every push to `main`, the `Release` workflow:
 
 1. tags the release `vX.Y.Z` and creates the GitHub release,
 2. builds the package with `uv build` and publishes it to PyPI with trusted publishing (OIDC),

src/app/__init__.py

@@ -1,3 +1,8 @@
 """Template python package."""
 
-__version__ = "0.1.0"
+from importlib.metadata import PackageNotFoundError, version
+
+try:
+    __version__ = version("template-python")
+except PackageNotFoundError:  # not installed, e.g. run from a source tree
+    __version__ = "0.0.0+unknown"