Simplify CI and use .python-version (#1140)

* Simplify CI and use .python-version

* Test CI on pypy 3.9 too

* We don't need .gitignore to keep the dir anymore

Author: hynek

.github/CONTRIBUTING.md

@@ -41,10 +41,17 @@ The official tag is `python-attrs` and helping out in support frees us up to imp
 
 You can (and should) run our test suite using [*tox*].
 However, you’ll probably want a more traditional environment as well.
-We highly recommend to develop using the latest Python release because we try to take advantage of modern features whenever possible.
-Also, running [*pre-commit*] later on will require the latest Python version.
 
-First [fork](https://github.com/python-attrs/attrs/fork) the repository on GitHub.
+First, create a [virtual environment](https://virtualenv.pypa.io/) so you don't break your system-wide Python installation.
+We recommend using the Python version from the `.python-version` file in project's root directory.
+
+If you're using [*direnv*](https://direnv.net), you can automate the creation of a virtual environment with the correct Python version by adding the following `.envrc` to the project root after you've cloned it to your computer:
+
+```bash
+layout python python$(cat .python-version)
+```
+
+Then, [fork](https://github.com/python-attrs/attrs/fork) the repository on GitHub.
 
 Clone the fork to your computer:
 

.github/workflows/ci.yml

@@ -14,10 +14,10 @@ env:
   TOX_TESTENV_PASSENV: FORCE_COLOR
   PIP_DISABLE_PIP_VERSION_CHECK: "1"
   PIP_NO_PYTHON_VERSION_WARNING: "1"
-  # Keep in sync with .pre-commit-config.yaml/default_language_version/python.
-  PYTHON_LATEST: "3.11"
   # Use oldest version used in doctests / examples.
   SETUPTOOLS_SCM_PRETEND_VERSION: "19.2.0"
+  # N.B. default Python version for setup-python comes from the .python-version
+  # file at the root of the project.
 
 permissions:
   contents: read
@@ -36,9 +36,10 @@ jobs:
           - "3.9"
           - "3.10"
           - "3.11"
-          - "~3.12.0-0"
+          - "3.12"
           - "pypy-3.7"
           - "pypy-3.8"
+          - "pypy-3.9"
 
     continue-on-error: >-
       ${{ contains(matrix.python-version, '~') && true || false }}
@@ -48,6 +49,8 @@ jobs:
       - uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python-version }}
+          allow-prereleases: true
+
       - run: python -Im pip install --upgrade wheel tox
 
       - name: Determine Python version for tox
@@ -82,9 +85,6 @@ jobs:
     steps:
       - uses: actions/checkout@v3
       - uses: actions/setup-python@v4
-        with:
-          # Use latest Python, so it understands all syntax.
-          python-version: ${{env.PYTHON_LATEST}}
 
       - run: python -Im pip install --upgrade coverage[toml]
 
@@ -131,12 +131,14 @@ jobs:
           - "3.9"
           - "3.10"
           - "3.11"
+          - "3.12"
 
     steps:
       - uses: actions/checkout@v3
       - uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python-version }}
+          allow-prereleases: true
 
       - run: python -Im pip install --upgrade wheel tox
       - run: python -Im tox run -e mypy
@@ -147,8 +149,6 @@ jobs:
     steps:
       - uses: actions/checkout@v3
       - uses: actions/setup-python@v4
-        with:
-          python-version: ${{env.PYTHON_LATEST}}
 
       - run: python -Im pip install --upgrade wheel tox
       - run: python -Im tox run -e pyright
@@ -163,8 +163,7 @@ jobs:
     steps:
       - uses: actions/checkout@v3
       - uses: actions/setup-python@v4
-        with:
-          python-version: ${{env.PYTHON_LATEST}}
+
       - run: python -Im pip install -e .[dev]
       - run: python -Ic 'import attr; print(attr.__version__)'
       - run: python -Ic 'import attrs; print(attrs.__version__)'

.pre-commit-config.yaml

@@ -3,7 +3,7 @@ ci:
   autoupdate_schedule: monthly
 
 default_language_version:
-  # Keep in sync with ci.yml/PYTHON_LATEST
+  # Keep in-sync with .python-version
   python: python3.11
 
 repos:

.python-version

@@ -0,0 +1 @@
+3.11

changelog.d/.gitignore

@@ -4,7 +4,7 @@ isolated_build = True
 
 
 [testenv:docs]
-# Keep basepython in sync with ci.yml/docs and .readthedocs.yaml.
+# Keep basepython in-sync with ci.yml/docs and .readthedocs.yaml.
 basepython = python3.11
 extras = docs
 commands =
@@ -31,6 +31,7 @@ commands = coverage run -m pytest {posargs:-n auto}
 
 
 [testenv:coverage-report]
+# Keep basepython in-sync with .python-version
 basepython = python3.11
 depends = py3{7,10,11}
 skip_install = true