[PATCH v2 01/12] python: convert packages to PEP517/pyproject.toml

[John Snow <jsnow@redhat.com>]

Newer versions of setuptools increasingly expect that packages are
defined using the pyproject.toml/PEP517 packaging layout format. With
3.9 as our minimum, I believe it's finally appropriate to make the shift
away from the legacy packaging format.

Update documentation and dependencies that change as a result of the
different build/packaging/installation pathways.

This change has the effect of fixing "make check-dev", which has been
broken on newer versions of Fedora for a while, now.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 python/README.rst        | 33 ++++++++++++++++-----------------
 python/Makefile          | 18 +++++++++---------
 python/pyproject.toml    | 10 ++++++++++
 python/setup.py          | 40 ----------------------------------------
 python/tests/minreqs.txt |  2 +-
 5 files changed, 36 insertions(+), 67 deletions(-)
 create mode 100644 python/pyproject.toml
 delete mode 100755 python/setup.py

diff --git a/python/README.rst b/python/README.rst
index d62e71528d2..befa84e3261 100644
--- a/python/README.rst
+++ b/python/README.rst
@@ -5,24 +5,23 @@ This directory houses Python tooling used by the QEMU project to build,
 configure, and test QEMU. It is organized by namespace (``qemu``), and
 then by package (e.g. ``qemu/machine``, ``qemu/qmp``, etc).
 
-``setup.py`` is used by ``pip`` to install this tooling to the current
-environment. ``setup.cfg`` provides the packaging configuration used by
-``setup.py``. You will generally invoke it by doing one of the following:
+``pyproject.toml`` and ``setup.cfg`` are used by ``pip`` to install this
+tooling to the current environment. ``setup.cfg`` provides the packaging
+configuration, while ``pyproject.toml`` describes the package build
+system requirements.
 
-1. ``pip3 install .`` will install these packages to your current
-   environment. If you are inside a virtual environment, they will
-   install there. If you are not, it will attempt to install to the
-   global environment, which is **not recommended**.
+You will generally install these packages by invoking ``pip3 install
+.``; which will install these packages to your current environment. If
+you are inside a virtual environment, they will install there. If you
+are not, modern versions of pip will attempt instead to install to your
+local user environment. Older versions of pip will attempt to install to
+the global environment, which is **not recommended**.
 
-2. ``pip3 install --user .`` will install these packages to your user's
-   local python packages. If you are inside of a virtual environment,
-   this will fail; you want the first invocation above.
-
-If you append the ``--editable`` or ``-e`` argument to either invocation
-above, pip will install in "editable" mode. This installs the package as
-a forwarder ("qemu.egg-link") that points to the source tree. In so
-doing, the installed package always reflects the latest version in your
-source tree.
+If you append the ``--editable`` or ``-e`` argument to the above
+invocation, pip will install in "editable" mode. This installs the
+package as a "forwarder" that points to the source tree, so that the
+installed package always reflects the latest version in your source
+tree.
 
 Installing ".[devel]" instead of "." will additionally pull in required
 packages for testing this package. They are not runtime requirements,
@@ -81,4 +80,4 @@ Files in this directory
 - ``VERSION`` contains the PEP-440 compliant version used to describe
   this package; it is referenced by ``setup.cfg``.
 - ``setup.cfg`` houses setuptools package configuration.
-- ``setup.py`` is the setuptools installer used by pip; See above.
+- ``pyproject.toml`` lists build system requirements for the Python packages.
diff --git a/python/Makefile b/python/Makefile
index 764b79ccb23..845fbb66cf4 100644
--- a/python/Makefile
+++ b/python/Makefile
@@ -15,8 +15,8 @@ help:
 	@echo "make check-tox:"
 	@echo "    Run tests against multiple python versions."
 	@echo "    These tests use the newest dependencies."
-	@echo "    Requires: Python 3.9 - 3.11, and tox."
-	@echo "    Hint (Fedora): 'sudo dnf install python3-tox python3.11'"
+	@echo "    Requires: Python 3.9 - 3.13, and tox."
+	@echo "    Hint (Fedora): 'sudo dnf install python3-tox python3.13'"
 	@echo "    The variable QEMU_TOX_EXTRA_ARGS can be use to pass extra"
 	@echo "    arguments to tox".
 	@echo ""
@@ -63,12 +63,12 @@ $(QEMU_MINVENV_DIR) $(QEMU_MINVENV_DIR)/bin/activate: setup.cfg tests/minreqs.tx
 	@(								\
 		echo "ACTIVATE $(QEMU_MINVENV_DIR)";			\
 		. $(QEMU_MINVENV_DIR)/bin/activate;			\
-		echo "INSTALL wheel $(QEMU_MINVENV_DIR)";               \
-		$(PIP_INSTALL) wheel 1>/dev/null;		               \
+		echo "INSTALL wheel $(QEMU_MINVENV_DIR)";		\
+		$(PIP_INSTALL) wheel 1>/dev/null;			\
 		echo "INSTALL -r tests/minreqs.txt $(QEMU_MINVENV_DIR)";\
 		$(PIP_INSTALL) -r tests/minreqs.txt 1>/dev/null;	\
 		echo "INSTALL -e qemu $(QEMU_MINVENV_DIR)";		\
-		$(PIP_INSTALL) -e . 1>/dev/null;			\
+		$(PIP_INSTALL) -e . --config-settings=editable_mode=compat 1>/dev/null;			\
 	)
 	@touch $(QEMU_MINVENV_DIR)
 
@@ -103,7 +103,7 @@ check-dev: dev-venv
 
 .PHONY: develop
 develop:
-	$(PIP_INSTALL) -e .[devel]
+	$(PIP_INSTALL) -e .[devel] --config-settings=editable_mode=compat
 
 .PHONY: check
 check:
@@ -122,12 +122,12 @@ check-coverage:
 
 .PHONY: clean
 clean:
-	python3 setup.py clean --all
-	rm -f pyproject.toml
+	rm -rf build/
 
 .PHONY: distclean
 distclean: clean
-	rm -rf qemu.egg-info/ .eggs/ dist/
+	rm -rf qemu.egg-info/
 	rm -rf $(QEMU_VENV_DIR) $(QEMU_MINVENV_DIR) .tox/
+	rm -rf .mypy_cache/
 	rm -f .coverage .coverage.*
 	rm -rf htmlcov/
diff --git a/python/pyproject.toml b/python/pyproject.toml
new file mode 100644
index 00000000000..2de34bf4729
--- /dev/null
+++ b/python/pyproject.toml
@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+[build-system]
+requires = [
+    "setuptools>=39.2",
+    "wheel",
+]
+build-backend = "setuptools.build_meta"
+
+[tool.setuptools_scm]
diff --git a/python/setup.py b/python/setup.py
deleted file mode 100755
index c5bc45919a4..00000000000
--- a/python/setup.py
+++ /dev/null
@@ -1,40 +0,0 @@
-#!/usr/bin/env python3
-"""
-QEMU tooling installer script
-Copyright (c) 2020-2021 John Snow for Red Hat, Inc.
-"""
-
-import setuptools
-from setuptools.command import bdist_egg
-import sys
-import pkg_resources
-
-
-class bdist_egg_guard(bdist_egg.bdist_egg):
-    """
-    Protect against bdist_egg from being executed
-
-    This prevents calling 'setup.py install' directly, as the 'install'
-    CLI option will invoke the deprecated bdist_egg hook. "pip install"
-    calls the more modern bdist_wheel hook, which is what we want.
-    """
-    def run(self):
-        sys.exit(
-            'Installation directly via setup.py is not supported.\n'
-            'Please use `pip install .` instead.'
-        )
-
-
-def main():
-    """
-    QEMU tooling installer
-    """
-
-    # https://medium.com/@daveshawley/safely-using-setup-cfg-for-metadata-1babbe54c108
-    pkg_resources.require('setuptools>=39.2')
-
-    setuptools.setup(cmdclass={'bdist_egg': bdist_egg_guard})
-
-
-if __name__ == '__main__':
-    main()
diff --git a/python/tests/minreqs.txt b/python/tests/minreqs.txt
index cd2e2a81c3d..e9edfa55eb7 100644
--- a/python/tests/minreqs.txt
+++ b/python/tests/minreqs.txt
@@ -15,6 +15,7 @@
 # also pin setuptools to version 70 or below. Otherwise, the
 # installation of the QEMU package itself fails, failing to find
 # setuptools.
+# Avocado also appears to require an older setuptools.
 setuptools<=70
 
 # Dependencies for qapidoc/qapi_domain et al
@@ -55,7 +56,6 @@ astroid==2.15.4
 dill==0.2
 lazy-object-proxy==1.4.0
 platformdirs==2.2.0
-toml==0.10.0
 tomlkit==0.10.1
 wrapt==1.14.0
 
-- 
2.48.1