fix: Use shutil.which over distutils.spawn.find_executable when possible

.github/workflows/build.yml

@@ -226,6 +226,13 @@ jobs:
         python3 -c 'import pyxrootd; print(pyxrootd)'
         python3 -c 'from XRootD import client; print(client.FileSystem("root://someserver:1094"))'
 
+    - name: Build sdist using publishing workflow
+      run: |
+        . /opt/rh/devtoolset-7/enable
+        cp packaging/wheel/* .
+        ./publish.sh
+        ls -lhtra dist/
+
   sdist-centos7:
 
     runs-on: ubuntu-latest

bindings/python/setup_pypi.py

@@ -3,7 +3,6 @@
 from distutils import sysconfig
 from os import getenv, walk, path, path, getcwd, chdir
 from platform import system
-import subprocess
 
 # Remove the "-Wstrict-prototypes" compiler option, which isn't valid for C++.
 cfg_vars = sysconfig.get_config_vars()

packaging/rhel/xrootd.spec.in

@@ -107,13 +107,17 @@ BuildRequires: json-c-devel
 
 %if %{python2only}
 BuildRequires: python2-devel
+BuildRequires: python2-setuptools
 %endif
 %if %{python2and3}
 BuildRequires: python2-devel
+BuildRequires: python2-setuptools
 BuildRequires: python%{python3_pkgversion}-devel
+BuildRequires: python%{python3_pkgversion}-setuptools
 %endif
 %if %{python3only}
 BuildRequires: python%{python3_pkgversion}-devel
+BuildRequires: python%{python3_pkgversion}-setuptools
 %endif
 
 BuildRequires: openssl-devel

packaging/wheel/install.sh

@@ -38,15 +38,28 @@ if [ "$res" -ne "0" ]; then
 fi
 
 cd ../bindings/python
-$6 setup.py install $3 # $6 holds the python sys.executable
-res=$?
+
+# Determine if shutil.which is available for a modern Python package install
+${6} -c 'import shutil.which' &> /dev/null  # $6 holds the python sys.executable
+shutil_which_available=$?
+if [ "${shutil_which_available}" -ne "0" ]; then
+    ${6} setup.py install ${3}
+    res=$?
+else
+    ${6} -m pip install ${3} .
+    res=$?
+fi
+unset shutil_which_available
+
 if [ "$res" -ne "0" ]; then
     exit 1
 fi
 
 cd $startdir
 rm -r xrootdbuild
 
+# TODO: Remove all of the below and build a wheel using PyPA tools
+
 # convert the egg-info into a proper dist-info
 egginfo_path=$(ls $1/xrootd-*.egg-info)
 core="${egginfo_path%.*}"

packaging/wheel/publish.sh

@@ -5,4 +5,35 @@ version=$(./genversion.sh --print-only)
 version=${version#v}
 echo $version > bindings/python/VERSION
 rm -r dist
-python3 setup.py sdist
+
+# Determine if wheel.bdist_wheel is available for wheel.bdist_wheel in setup.py
+python3 -c 'import wheel' &> /dev/null
+wheel_available=$?
+if [ "${wheel_available}" -ne "0" ]; then
+    python3 -m pip install wheel
+    wheel_available=$?
+
+    if [ "${wheel_available}" -ne "0" ]; then
+        echo "ERROR: Unable to find wheel and unable to install wheel with '$(command -v python3) -m pip install wheel'."
+        echo "       Please ensure wheel is available to $(command -v python3) and try again."
+        exit 1
+    fi
+fi
+unset wheel_available
+
+# Determine if build is available
+python3 -c 'import build' &> /dev/null
+build_available=$?
+if [ "${build_available}" -ne "0" ]; then
+    python3 -m pip install build
+    build_available=$?
+fi
+
+if [ "${build_available}" -ne "0" ]; then
+    echo "WARNING: Unable to find build and unable to install build from PyPI with '$(command -v python3) -m pip install build'."
+    echo "         Falling back to building sdist with '$(command -v python3) setup.py sdist'."
+    python3 setup.py sdist
+else
+    python3 -m build --sdist .
+fi
+unset build_available

packaging/wheel/setup.py

@@ -1,11 +1,17 @@
-from setuptools import setup, Extension
+from setuptools import setup
 from setuptools.command.install import install
 from setuptools.command.sdist import sdist
 from wheel.bdist_wheel import bdist_wheel
 
+# shutil.which was added in Python 3.3
+# c.f. https://docs.python.org/3/library/shutil.html#shutil.which
+try:
+    from shutil import which
+except ImportError:
+    from distutils.spawn import find_executable as which
+
 import subprocess
 import sys
-import getpass
 
 def get_version():
     version = subprocess.check_output(['./genversion.sh', '--print-only'])
@@ -27,11 +33,9 @@ def get_version_from_file():
 
 def binary_exists(name):
     """Check whether `name` is on PATH."""
-    from distutils.spawn import find_executable
-    return find_executable(name) is not None
+    return which(name) is not None
 
 def check_cmake3(path):
-    from distutils.spawn import find_executable
     args = (path, "--version")
     popen = subprocess.Popen(args, stdout=subprocess.PIPE)
     popen.wait()
@@ -42,12 +46,11 @@ def check_cmake3(path):
 
 def cmake_exists():
     """Check whether CMAKE is on PATH."""
-    from distutils.spawn import find_executable
-    path = find_executable('cmake')
+    path = which('cmake')
     if path is not None:
         if check_cmake3(path): return True, path
-    path = find_executable('cmake3')
-    return path is not None, path 
+    path = which('cmake3')
+    return path is not None, path
 
 def is_rhel7():
     """check if we are running on rhel7 platform"""
@@ -78,9 +81,8 @@ def has_cxx14():
 
 # def python_dependency_name( py_version_short, py_version_nodot ):
 #     """ find the name of python dependency """
-#     from distutils.spawn import find_executable
 #     # this is the path to default python
-#     path = find_executable( 'python' )
+#     path = which( 'python' )
 #     from os.path import realpath
 #     # this is the real default python after resolving symlinks
 #     real = realpath(path)