Safe wheel import (#905)

Only allow wheel commands if wheel is installed

AUTHORS.md

@@ -19,6 +19,7 @@
 -   Callum Noble ([@callumnoble](https://github.com/callumnoble))
 -   Christian Heimes ([@tiran](https://github.com/tiran))
 -   Christoph Gohlke ([@cgohlke](https://github.com/cgohlke))
+-   Christopher Bremner ([@chrisjbremner](https://github.com/chrisjbremner))
 -   Christopher Pow ([@christopherpow](https://github.com/christopherpow))
 -   Daniel Fernandez ([@fdanny](https://github.com/fdanny))
 -   Daniel Santana ([@dgsantana](https://github.com/dgsantana))

CHANGELOG.md

@@ -14,6 +14,7 @@ This document follows the conventions laid out in [Keep a CHANGELOG][].
 ### Changed
 
 -   Added argument types information to "No method matches given arguments" message
+-   Moved wheel import in setup.py inside of a try/except to prevent pip collection failures
 
 ### Fixed
 

setup.py

@@ -15,10 +15,14 @@ import sys
 import sysconfig
 from distutils import spawn
 from distutils.command import install, build, build_ext, install_data, install_lib
-from wheel import bdist_wheel
 
 from setuptools import Extension, setup
 
+try:
+    from wheel import bdist_wheel
+except ImportError:
+    bdist_wheel = None
+
 # Allow config/verbosity to be set from cli
 # http://stackoverflow.com/a/4792601/5208670
 CONFIG = "Release"  # Release or Debug
@@ -594,21 +598,21 @@ class InstallPythonnet(install.install):
             _update_xlat_devtools()
         return install.install.run(self)
 
+if bdist_wheel:
+    class BDistWheelPythonnet(bdist_wheel.bdist_wheel):
+        user_options = bdist_wheel.bdist_wheel.user_options + [("xplat", None, None)]
 
-class BDistWheelPythonnet(bdist_wheel.bdist_wheel):
-    user_options = bdist_wheel.bdist_wheel.user_options + [("xplat", None, None)]
+        def initialize_options(self):
+            bdist_wheel.bdist_wheel.initialize_options(self)
+            self.xplat = None
 
-    def initialize_options(self):
-        bdist_wheel.bdist_wheel.initialize_options(self)
-        self.xplat = None
+        def finalize_options(self):
+            bdist_wheel.bdist_wheel.finalize_options(self)
 
-    def finalize_options(self):
-        bdist_wheel.bdist_wheel.finalize_options(self)
-
-    def run(self):
-        if self.xplat:
-            _update_xlat_devtools()
-        return bdist_wheel.bdist_wheel.run(self)
+        def run(self):
+            if self.xplat:
+                _update_xlat_devtools()
+            return bdist_wheel.bdist_wheel.run(self)
 
         ###############################################################################
 
@@ -621,6 +625,15 @@ setup_requires = []
 if not os.path.exists(_get_interop_filename()):
     setup_requires.append("pycparser")
 
+cmdclass={
+    "install": InstallPythonnet,
+    "build_ext": BuildExtPythonnet,
+    "install_lib": InstallLibPythonnet,
+    "install_data": InstallDataPythonnet,
+}
+if bdist_wheel:
+    cmdclass["bdist_wheel"] = BDistWheelPythonnet
+
 setup(
     name="pythonnet",
     version="2.4.1-dev",
@@ -633,13 +646,7 @@ setup(
     long_description=_get_long_description(),
     ext_modules=[Extension("clr", sources=list(_get_source_files()))],
     data_files=[("{install_platlib}", ["{build_lib}/Python.Runtime.dll"])],
-    cmdclass={
-        "install": InstallPythonnet,
-        "build_ext": BuildExtPythonnet,
-        "install_lib": InstallLibPythonnet,
-        "install_data": InstallDataPythonnet,
-        "bdist_wheel": BDistWheelPythonnet,
-    },
+    cmdclass=cmdclass,
     classifiers=[
         "Development Status :: 5 - Production/Stable",
         "Intended Audience :: Developers",