cygclass python-wheel setup.cfg-only projects

[Jon Turney]

On 02/12/2022 12:10, Jon Turney wrote:
> On 01/12/2022 22:20, Libor Ukropec wrote:
>> Hello,
>>
>> I have question to cygclass python-wheel. It seems that setup.py is 
>> being omited in some python packages (here I faced it in the 
>> python-fasteners) and as described here: 
>> https://setuptools.pypa.io/en/latest/setuptools.html , chapter 
>> "setup.cfg-only projects"
>>
>>  > If setup.py is missing from the project directory when a PEP 517 
>> build is invoked,
>>  > setuptools emulates a dummy setup.py file containing only a 
>> setuptools.setup() call.
>>
>> Currently the cyglass requires the setup.py being present, otherwise 
>> it throws error "No Python Distutils module detected"
>>
>> IMHO would be nice if the cygclass handle this case. Or should I 
>> create a patch that inserts empty setup.py module instead?
> 
> Yeah, it seems this is definitely something that needs updating in 
> cygport, so thanks for pointing that out.
> 
> It's fairly straightforward to drop the check at [1], or perhaps it's 
> more appropriate to change it to check for either setup.py or setup.cfg?
> 
> But then we want to run 'python -msetuptools.launch setup.py 
> bdist_wheel' to build the wheel.
> 
> In a very quick bit of research, it' seems the modern equivalent would 
> be something like 'python -m build --wheel', but we don't seem to have a 
> python-build package?

The other alternative seems to be 'pip wheel'

Attached is a cygport patch which uses that for the setup.py-less case.

(possibly we could use it in all cases, but I'm being conservative with 
this change)

> I'm not very familiar with the evolving state of python packaging, so I 
> think I may need a bit of help getting this right!
-------------- next part --------------
From a44b2e970293b34062da61844f7071fae70a230c Mon Sep 17 00:00:00 2001
From: Jon Turney <jon.turney@dronecode.org.uk>
Date: Fri, 2 Dec 2022 11:50:33 +0000
Subject: [PATCH cygport] python-wheel: Handle projects without a setup.py

Since setuptools 40.9.0, projects can have just a setup.cfg, and a
default setup.py is emulated.

Rather than setuptools, use 'pip wheel' to build the wheel.

Note: possibly could use pypa build module to do the build, but we need
pip for the install anyhow?
---
 cygclass/python-wheel.cygclass | 28 +++++++++++++++++-----------
 1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/cygclass/python-wheel.cygclass b/cygclass/python-wheel.cygclass
index b6ed68b..4d97945 100644
--- a/cygclass/python-wheel.cygclass
+++ b/cygclass/python-wheel.cygclass
@@ -24,9 +24,10 @@
 #****h* Cygclasses/python-wheel.cygclass
 #  DESCRIPTION
 #  Wheels are the new standard for installing Python libraries and programs.
-#  The build is defined by a setup.py file in the top source directory, which
-#  controls the installation of files and the building of C Python extensions.
-#  Many such packages are hosted on the Python Package Index (PyPI).
+#  The build is defined by a PEP 517 conformant source tree, or by a top-level
+#  setup.py file, which controls the installation of files and the building of C
+#  Python extensions.  Many such packages are hosted on the Python Package Index
+#  (PyPI).
 #
 #  This cygclass handles the building of wheel-based Python module packages
 #  for multiple Python versions simultaneously.
@@ -148,23 +149,28 @@ fi
 #  SYNOPSIS
 #  python_wheel_compile [OPTIONS]
 #  DESCRIPTION
-#  Runs the setup.py 'bdist_wheel' command, to which any arguments are passed.
-#****
+#  Runs 'pip wheel', or the setup.py 'bdist_wheel' command, to which any
+#  arguments are passed.  ****
 python_wheel_compile() {
 	local ver
 
-	if [ ! -e setup.py ]
+	if [ ! -e setup.py ] && [ ! -e setup.cfg ]
 	then
-		error "No Python Distutils module detected"
+		error "No Python Distutils module detected in source tree"
 	fi
 
 	for ver in ${PYTHON_WHEEL_VERSIONS//:/ }
 	do
 		[ ! -d build/lib ] || find build/lib -delete
-		# setuptools.launch imports setuptools hooks regardles of setup.py
 		if [ ! -f dist/*-py2.py3*-none-any.whl -a ! -f dist/*py${ver:0:1}-none-any.whl ]
 		then
-			/usr/bin/python${ver} -msetuptools.launch setup.py bdist_wheel "${@}" || error "setup.py bdist_wheel failed"
+			if [ ! -e setup.py ]
+			then
+				pip${ver} wheel --no-deps -w dist . || error "pip${ver} wheel failed"
+			else
+				# setuptools.launch imports setuptools hooks regardles of setup.py
+				/usr/bin/python${ver} -msetuptools.launch setup.py bdist_wheel "${@}" || error "setup.py bdist_wheel failed"
+			fi
 		fi
 	done
 }
@@ -178,9 +184,9 @@ python_wheel_compile() {
 python_wheel_install() {
 	local ver whl
 
-	if [ ! -e setup.py ]
+	if [ ! -e setup.py ] && [ ! -e setup.cfg ]
 	then
-		error "No Python Distutils module detected"
+		error "No Python Distutils module detected in source tree"
 	fi
 
 	for ver in ${PYTHON_WHEEL_VERSIONS//:/ }
-- 
2.38.1