py-hatchling: add new packages, document new build backend (#31512)

* py-hatchling: add new package, document new build backend

* Minor doc changes

Co-authored-by: Tamara Dahlgren <35777542+tldahlgren@users.noreply.github.com>

Co-authored-by: Tamara Dahlgren <35777542+tldahlgren@users.noreply.github.com>

lib/spack/docs/build_systems/pythonpackage.rst

@@ -48,8 +48,9 @@ important to understand.
 **build backend**
    Libraries used to define how to build a wheel. Examples
    include `setuptools <https://setuptools.pypa.io/>`__,
-   `flit <https://flit.readthedocs.io/>`_, and
+   `flit <https://flit.readthedocs.io/>`_,
-   `poetry <https://python-poetry.org/>`_.
+   `poetry <https://python-poetry.org/>`_, and
+   `hatchling <https://hatch.pypa.io/latest/>`_.
 
 ^^^^^^^^^^^
 Downloading
@@ -326,6 +327,33 @@ for specifying the version requirements. Note that ``~=`` works
 differently in poetry than in setuptools and flit for versions that
 start with a zero.
 
+"""""""""
+hatchling
+"""""""""
+
+If the ``pyproject.toml`` lists ``hatchling.build`` as the
+``build-backend``, it uses the hatchling build system. Look for
+dependencies under the following keys:
+
+* ``requires-python``
+
+  This specifies the version of Python that is required
+
+* ``project.dependencies``
+
+  These packages are required for building and installation. You can
+  add them with ``type=('build', 'run')``.
+
+* ``project.optional-dependencies``
+
+  This section includes keys with lists of optional dependencies
+  needed to enable those features. You should add a variant that
+  optionally adds these dependencies. This variant should be ``False``
+  by default.
+
+See https://hatch.pypa.io/latest/config/dependency/ for more
+information.
+
 """"""
 wheels
 """"""
@@ -666,3 +694,4 @@ For more information on build backend tools, see:
 * setuptools: https://setuptools.pypa.io/
 * flit: https://flit.readthedocs.io/
 * poetry: https://python-poetry.org/
+* hatchling: https://hatch.pypa.io/latest/

var/spack/repos/builtin/packages/py-editables/package.py

@@ -0,0 +1,18 @@
+# Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+from spack.package import *
+
+
+class PyEditables(PythonPackage):
+    """A Python library for creating "editable wheels"."""
+
+    homepage = "https://github.com/pfmoore/editables"
+    pypi     = "editables/editables-0.3.tar.gz"
+
+    version('0.3', sha256='167524e377358ed1f1374e61c268f0d7a4bf7dbd046c656f7b410cde16161b1a')
+
+    depends_on('python@3.7:', type=('build', 'run'))
+    depends_on('py-setuptools@42:', type='build')

var/spack/repos/builtin/packages/py-hatchling/package.py

@@ -0,0 +1,23 @@
+# Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+from spack.package import *
+
+
+class PyHatchling(PythonPackage):
+    """Modern, extensible Python build backend."""
+
+    homepage = "https://hatch.pypa.io/latest/"
+    pypi     = "hatchling/hatchling-1.4.1.tar.gz"
+
+    version('1.4.1', sha256='13461b42876ade4f75ee5d2a2c656b288ca0aab7f048ef66657ef166996b2118')
+
+    depends_on('python@3.7:', type=('build', 'run'))
+    depends_on('py-editables@0.3:', type=('build', 'run'))
+    depends_on('py-importlib-metadata', when='^python@:3.7', type=('build', 'run'))
+    depends_on('py-packaging@21.3:', type=('build', 'run'))
+    depends_on('py-pathspec@0.9:', type=('build', 'run'))
+    depends_on('py-pluggy@1:', type=('build', 'run'))
+    depends_on('py-tomli@1.2.2:', when='^python@:3.10', type=('build', 'run'))