build: Switch to using Hatchling as build backend (#2095)

* Migrate build system to Hatchling and add Hatch configuration in
  pyproject.toml.
   - Use pip v21.2+'s ability to handle recursive dependencies to define
     nested extras.
     c.f. https://hynek.me/articles/python-recursive-optional-dependencies/
   - Use hatch-vcs to dynamically determine the version information from Git.
   - Use 'only-include' option with `[tool.hatch.build.targets.sdist]` to avoid
     problem with hatchling discovering the symlink of src/pyhf/schemas under
     docs/ before src/ and skipping including it in the sdist.
     c.f. #791 and
          pypa/hatch#276
* Remove all setuptools related files: setup.py, setup.cfg, MANIFEST.in.
* Add .flake8 config file as the config for flake8 had previously been in setup.cfg
  as flake8 doesn't support pyproject.toml.
* Remove use of check-manifest from packaging GitHub Actions workflow.
* Remove mention of setup.cfg from release checklist.
* Add Scikit-HEP admins info to maintainers metadata.

Co-authored-by: Angus Hollands <[email protected]>
Co-authored-by: Ofek Lev <[email protected]>

.flake8

@@ -0,0 +1,6 @@
+[flake8]
+# E203: whitespace before ':'
+# E402: module level import not at top of file
+# E501: line too long
+extend-ignore = E203, E402, E501
+max-line-length = 88

.github/ISSUE_TEMPLATE/~release-checklist.md

@@ -32,7 +32,7 @@ about: Checklist for core developers to complete as part of making a release
 * [ ] Verify that a Binder has properly built for the new release.
 * [ ] Watch for a GitHub notification that there is an automatic PR to the [Conda-forge feedstock](https://github.com/conda-forge/pyhf-feedstock). This may take multiple hours to happen. If there are any changes needed to the Conda-forge release make them **from a personal account** and not from an organization account to have workflows properly trigger.
    - [ ] Check if any requirements need to be updated by commenting "@conda-grayskull show requirements" on the PR.
-   - [ ] Verify the requirements in the [Conda-forge feedstock](https://github.com/conda-forge/pyhf-feedstock) recipe `meta.yaml` match those in `setup.cfg` and `pyproject.toml`.
+   - [ ] Verify the requirements in the [Conda-forge feedstock](https://github.com/conda-forge/pyhf-feedstock) recipe `meta.yaml` match those in `pyproject.toml`.
 
 ## After Release
 

.github/workflows/publish-package.yml

@@ -37,16 +37,12 @@ jobs:
       with:
         python-version: '3.10'
 
-    - name: Install python-build, check-manifest, and twine
+    - name: Install python-build and twine
       run: |
-        python -m pip install --upgrade pip setuptools wheel
-        python -m pip install build check-manifest twine
+        python -m pip install --upgrade pip
+        python -m pip install build twine
         python -m pip list
 
-    - name: Check MANIFEST
-      run: |
-        check-manifest
-
     - name: Build a wheel and a sdist
       run: |
         PYTHONWARNINGS=error,default::DeprecationWarning python -m build .

pyproject.toml

@@ -1,12 +1,149 @@
 [build-system]
-# Minimum requirements for the build system to execute.
-requires = ["setuptools>=61.0.0", "setuptools_scm>=7.0.1"]
-build-backend = "setuptools.build_meta"
+requires = ["hatchling>=1.0.0", "hatch-vcs"]
+build-backend = "hatchling.build"
 
-[tool.setuptools_scm]
-write_to = "src/pyhf/_version.py"
+[project]
+name = "pyhf"
+dynamic = ["version"]
+description = "pure-Python HistFactory implementation with tensors and autodiff"
+readme = "README.rst"
+license = { text = "Apache-2.0" }  # SPDX short identifier
+requires-python = ">=3.8"
+authors = [
+    { name = "Lukas Heinrich", email = "[email protected]" },
+    { name = "Matthew Feickert", email = "[email protected]" },
+    { name = "Giordon Stark", email = "[email protected]" },
+]
+maintainers = [ {name = "The Scikit-HEP admins", email = "[email protected]"} ]
+keywords = [
+    "fitting",
+    "jax",
+    "numpy",
+    "physics",
+    "pytorch",
+    "scipy",
+    "tensorflow",
+]
+classifiers = [
+    "Development Status :: 4 - Beta",
+    "Intended Audience :: Science/Research",
+    "License :: OSI Approved :: Apache Software License",
+    "Programming Language :: Python :: 3",
+    "Programming Language :: Python :: 3 :: Only",
+    "Programming Language :: Python :: 3.8",
+    "Programming Language :: Python :: 3.9",
+    "Programming Language :: Python :: 3.10",
+    "Programming Language :: Python :: Implementation :: CPython",
+    "Topic :: Scientific/Engineering",
+    "Topic :: Scientific/Engineering :: Physics",
+]
+dependencies = [
+    "click>=8.0.0",  # for console scripts
+    "importlib_resources>=1.4.0; python_version < '3.9'",  # for resources in schema
+    "jsonpatch>=1.15",
+    "jsonschema>=4.15.0",  # for utils
+    "pyyaml>=5.1",  # for parsing CLI equal-delimited options
+    "scipy>=1.5.1",  # requires numpy, which is required by pyhf and tensorflow
+    "tqdm>=4.56.0",  # for readxml
+    "numpy",  # compatible versions controlled through scipy
+]
+
+[project.scripts]
+pyhf = "pyhf.cli:cli"
+
+[project.urls]
+Documentation = "https://pyhf.readthedocs.io/"
+Homepage = "https://github.com/scikit-hep/pyhf"
+"Issue Tracker" = "https://github.com/scikit-hep/pyhf/issues"
+"Release Notes" = "https://pyhf.readthedocs.io/en/stable/release-notes.html"
+"Source Code" = "https://github.com/scikit-hep/pyhf"
+
+[project.optional-dependencies]
+shellcomplete = ["click_completion"]
+tensorflow = [
+    "tensorflow>=2.7.0",  # c.f. PR #1962
+    "tensorflow-probability>=0.11.0",  # c.f. PR #1657
+]
+torch = ["torch>=1.10.0"]  # c.f. PR #1657
+jax = [
+    "jax>=0.4.1",  # c.f. PR #2079
+    "jaxlib>=0.4.1",  # c.f. PR #2079
+]
+xmlio = ["uproot>=4.1.1"]  # c.f. PR #1567
+minuit = ["iminuit>=2.7.0"]  # c.f. PR #1895
+contrib = [
+    "matplotlib>=3.0.0",
+    "requests>=2.22.0",
+]
+backends = ["pyhf[tensorflow,torch,jax,minuit]"]
+all = ["pyhf[backends,xmlio,contrib,shellcomplete]"]
+
+# Developer extras
+test = [
+    "pyhf[all]",
+    "scikit-hep-testdata>=0.4.11",
+    "pytest>=6.0",
+    "coverage[toml]>=6.0.0",
+    "pytest-mock",
+    "requests-mock>=1.9.0",
+    "pytest-benchmark[histogram]",
+    "pytest-console-scripts",
+    "pytest-mpl",
+    "pydocstyle",
+    "papermill~=2.3.4",
+    "scrapbook~=0.5.0",
+    "jupyter",
+    "graphviz",
+    "pytest-socket>=0.2.0",  # c.f. PR #1917
+]
+docs = [
+    "pyhf[xmlio,contrib]",
+    "sphinx>=5.1.1",  # c.f. https://github.com/scikit-hep/pyhf/pull/1926
+    "sphinxcontrib-bibtex~=2.1",
+    "sphinx-click",
+    "sphinx_rtd_theme",
+    "nbsphinx!=0.8.8",  # c.f. https://github.com/spatialaudio/nbsphinx/issues/620
+    "ipywidgets",
+    "sphinx-issues",
+    "sphinx-copybutton>=0.3.2",
+    "sphinx-togglebutton>=0.3.0",
+    "ipython!=8.7.0",  # c.f. https://github.com/scikit-hep/pyhf/pull/2068
+]
+develop = [
+    "pyhf[test,docs]",
+    "tbump>=6.7.0",
+    "pre-commit",
+    "nox",
+    "codemetapy>=2.3.0",
+]
+
+[tool.hatch.version]
+source = "vcs"
+
+[tool.hatch.version.raw-options]
 local_scheme = "no-local-version"
 
+[tool.hatch.build.hooks.vcs]
+version-file = "src/pyhf/_version.py"
+
+[tool.hatch.build.targets.sdist]
+# only-include needed to properly include src/pyhf/schemas
+# c.f. https://github.com/pypa/hatch/pull/299
+only-include = [
+    "/src",
+    "/LICENSE",
+    "/README.rst",
+    "/pyproject.toml",
+    "/AUTHORS",
+    "/CITATION.cff"
+]
+exclude = [
+    "/src/conftest.py"
+]
+
+[tool.hatch.build.targets.wheel]
+packages = ["src/pyhf"]
+
 [tool.black]
 line-length = 88
 target-version = ['py38', 'py39', 'py310']
@@ -21,24 +158,6 @@ exclude = '''
 )/
 '''
 
-[tool.check-manifest]
-ignore = [
-    'docs*',
-    'validation*',
-    'examples*',
-    'tests*',
-    'docker*',
-    'binder*',
-    '.*',
-    'pyproject.toml',
-    'pytest.ini',
-    'codecov.yml',
-    'codemeta.json',
-    'CODE_OF_CONDUCT.md',
-    'CONTRIBUTING.md',
-    'AUTHORS',
-]
-
 [tool.pytest.ini_options]
 minversion = "6.0"
 xfail_strict = true