Project versioning: Use versioningit

DEVELOP.rst

@@ -114,8 +114,6 @@ To create a new release, you must:
 
 In the release branch:
 
-- Update ``__version__`` in ``src/crate/client/__init__.py``
-
 - Add a section for the new version in the ``CHANGES.rst`` file
 
 - Commit your changes with a message like "prepare release x.y.z"

pyproject.toml

@@ -1,12 +1,13 @@
 [build-system]
-requires = ["hatchling >= 1.26"]
+requires = ["hatchling >= 1.26", "versioningit"]
 build-backend = "hatchling.build"
 
 [tool.hatch.build.targets.wheel]
 packages = ["src/crate"]
 
 [tool.hatch.version]
-path = "src/crate/client/__init__.py"
+source = "versioningit"
+default-version = "0.0.0+unknown"
 
 [project]
 name = "crate"
@@ -32,6 +33,7 @@ classifiers = [
         "Topic :: Database",
 ]
 dependencies = [
+    "importlib-metadata; python_version<'3.8'",
     "orjson>=3.11.3",
     "urllib3",
     "verlib2>=0.3.1",

src/crate/client/__init__.py

@@ -27,9 +27,21 @@
     "Error",
 ]
 
-# version string read from setup.py using a regex. Take care not to break the
-# regex!
-__version__ = "2.0.0"
+# ruff: noqa: E402
+try:
+    from importlib.metadata import PackageNotFoundError, version
+except (ImportError, ModuleNotFoundError):  # pragma: no cover
+    from importlib_metadata import (  # type: ignore[assignment,no-redef,unused-ignore]
+        PackageNotFoundError,
+        version,
+    )
+
+__appname__ = "crate"
+
+try:
+    __version__ = version(__appname__)
+except PackageNotFoundError:  # pragma: no cover
+    __version__ = "unknown"
 
 # codeql[py/unused-global-variable]
 apilevel = "2.0"