Fix infinite process recursion on Windows

Author: mdboom

setup.py

@@ -20,17 +20,19 @@
 except AttributeError:
     pass
 
-# BEFORE importing distutils, remove MANIFEST. distutils doesn't properly
-# update it when the contents of directories change.
-if os.path.exists('MANIFEST'):
-    os.remove('MANIFEST')
+# This 'if' statement is needed to prevent spawning infinite processes
+# on Windows
+if __name__ == '__main__':
+    # BEFORE importing distutils, remove MANIFEST. distutils doesn't properly
+    # update it when the contents of directories change.
+    if os.path.exists('MANIFEST'):
+        os.remove('MANIFEST')
 
 try:
     from setuptools.core import setup
 except ImportError:
     from distutils.core import setup
 
-
 import setupext
 from setupext import print_line, print_raw, print_message, print_status
 
@@ -48,6 +50,7 @@
     'Required dependencies and extensions',
     setupext.Numpy(),
     setupext.Dateutil(),
+    setupext.Tornado(),
     setupext.Pyparsing(),
     setupext.CXX(),
     setupext.LibAgg(),
@@ -87,90 +90,6 @@
     ]
 
 
-# These are distutils.setup parameters that the various packages add
-# things to.
-packages = []
-py_modules = []
-ext_modules = []
-package_data = {}
-package_dir = {'': 'lib'}
-install_requires = []
-default_backend = None
-
-
-# Go through all of the packages and figure out which ones we are
-# going to build/install.
-print_line()
-print_raw("Edit setup.cfg to change the build options")
-
-
-required_failed = []
-good_packages = []
-for package in mpl_packages:
-    if isinstance(package, str):
-        print_raw('')
-        print_raw(package.upper())
-    else:
-        try:
-            result = package.check()
-            if result is not None:
-                message = 'yes [%s]' % result
-                print_status(package.name, message)
-        except setupext.CheckFailed as e:
-            print_status(package.name, 'no  [%s]' % str(e))
-            if not package.optional:
-                required_failed.append(package)
-        else:
-            good_packages.append(package)
-            if isinstance(package, setupext.OptionalBackendPackage):
-                if default_backend is None:
-                    default_backend = package.name
-print_raw('')
-
-
-# Abort if any of the required packages can not be built.
-if required_failed:
-    print_line()
-    print_message(
-        "The following required packages can not "
-        "be built: %s" %
-        ', '.join(x.name for x in required_failed))
-    sys.exit(1)
-
-
-# Now collect all of the information we need to build all of the
-# packages.
-for package in good_packages:
-    if isinstance(package, str):
-        continue
-    packages.extend(package.get_packages())
-    py_modules.extend(package.get_py_modules())
-    ext = package.get_extension()
-    if ext is not None:
-        ext_modules.append(ext)
-    data = package.get_package_data()
-    for key, val in data.items():
-        package_data.setdefault(key, [])
-        package_data[key] = list(set(val + package_data[key]))
-    install_requires.extend(package.get_install_requires())
-
-# Write the default matplotlibrc file
-if default_backend is None:
-    default_backend = 'svg'
-if setupext.options['backend']:
-    default_backend = setupext.options['backend']
-with open('matplotlibrc.template') as fd:
-    template = fd.read()
-with open('lib/matplotlib/mpl-data/matplotlibrc', 'w') as fd:
-    fd.write(template % {'backend': default_backend})
-
-
-# Build in verbose mode if requested
-if setupext.options['verbose']:
-    for mod in ext_modules:
-        mod.extra_compile_args.append('-DVERBOSE')
-
-
 classifiers = [
     'Development Status :: 5 - Production/Stable',
     'Intended Audience :: Science/Research',
@@ -181,47 +100,132 @@
     'Topic :: Scientific/Engineering :: Visualization',
     ]
 
-
-# Finally, pass this all along to distutils to do the heavy lifting.
-distrib = setup(name="matplotlib",
-      version=__version__,
-      description="Python plotting package",
-      author="John D. Hunter, Michael Droettboom",
-      author_email="mdroe@stsci.edu",
-      url="http://matplotlib.org",
-      long_description="""
-      matplotlib strives to produce publication quality 2D graphics
-      for interactive graphing, scientific publishing, user interface
-      development and web application servers targeting multiple user
-      interfaces and hardcopy output formats.  There is a 'pylab' mode
-      which emulates matlab graphics.
-      """,
-      download_url="https://downloads.sourceforge.net/project/matplotlib/matplotlib/matplotlib-{0}/matplotlib-{0}.tar.gz".format(__version__),
-      install_requires=['dateutils', 'tornado'],
-      license="BSD",
-      packages=packages,
-      platforms='any',
-      py_modules=py_modules,
-      ext_modules=ext_modules,
-      package_dir=package_dir,
-      package_data=package_data,
-      classifiers=classifiers,
-
-      # List third-party Python packages that we require
-      install_requires=install_requires,
-
-      # Automatically 2to3 source on Python 3.x
-      use_2to3=True,
-
-      # matplotlib has C/C++ extensions, so it's not zip safe.
-      # Telling setuptools this prevents it from doing an automatic
-      # check for zip safety.
-      zip_safe=False,
-
-      # Install our nose plugin so it will always be found
-      entry_points={
-          'nose.plugins.0.10': [
-              'KnownFailure = matplotlib.testing.noseclasses:KnownFailure'
-            ]
-        },
-     )
+# One doesn't normally see `if __name__ == '__main__'` blocks in a setup.py,
+# however, this is needed on Windows to avoid creating infinite subprocesses
+# when using multiprocessing.
+if __name__ == '__main__':
+    # These are distutils.setup parameters that the various packages add
+    # things to.
+    packages = []
+    py_modules = []
+    ext_modules = []
+    package_data = {}
+    package_dir = {'': 'lib'}
+    install_requires = []
+    default_backend = None
+
+
+    # Go through all of the packages and figure out which ones we are
+    # going to build/install.
+    print_line()
+    print_raw("Edit setup.cfg to change the build options")
+
+    required_failed = []
+    good_packages = []
+    for package in mpl_packages:
+        if isinstance(package, str):
+            print_raw('')
+            print_raw(package.upper())
+        else:
+            try:
+                result = package.check()
+                if result is not None:
+                    message = 'yes [%s]' % result
+                    print_status(package.name, message)
+            except setupext.CheckFailed as e:
+                print_status(package.name, 'no  [%s]' % str(e))
+                if not package.optional:
+                    required_failed.append(package)
+            else:
+                good_packages.append(package)
+                if isinstance(package, setupext.OptionalBackendPackage):
+                    if default_backend is None:
+                        default_backend = package.name
+    print_raw('')
+
+
+    # Abort if any of the required packages can not be built.
+    if required_failed:
+        print_line()
+        print_message(
+            "The following required packages can not "
+            "be built: %s" %
+            ', '.join(x.name for x in required_failed))
+        sys.exit(1)
+
+
+    # Now collect all of the information we need to build all of the
+    # packages.
+    for package in good_packages:
+        if isinstance(package, str):
+            continue
+        packages.extend(package.get_packages())
+        py_modules.extend(package.get_py_modules())
+        ext = package.get_extension()
+        if ext is not None:
+            ext_modules.append(ext)
+        data = package.get_package_data()
+        for key, val in data.items():
+            package_data.setdefault(key, [])
+            package_data[key] = list(set(val + package_data[key]))
+        install_requires.extend(package.get_install_requires())
+
+    # Write the default matplotlibrc file
+    if default_backend is None:
+        default_backend = 'svg'
+    if setupext.options['backend']:
+        default_backend = setupext.options['backend']
+    with open('matplotlibrc.template') as fd:
+        template = fd.read()
+    with open('lib/matplotlib/mpl-data/matplotlibrc', 'w') as fd:
+        fd.write(template % {'backend': default_backend})
+
+
+    # Build in verbose mode if requested
+    if setupext.options['verbose']:
+        for mod in ext_modules:
+            mod.extra_compile_args.append('-DVERBOSE')
+
+
+    # Finally, pass this all along to distutils to do the heavy lifting.
+    distrib = setup(name="matplotlib",
+          version=__version__,
+          description="Python plotting package",
+          author="John D. Hunter, Michael Droettboom",
+          author_email="mdroe@stsci.edu",
+          url="http://matplotlib.org",
+          long_description="""
+          matplotlib strives to produce publication quality 2D graphics
+          for interactive graphing, scientific publishing, user interface
+          development and web application servers targeting multiple user
+          interfaces and hardcopy output formats.  There is a 'pylab' mode
+          which emulates matlab graphics.
+          """,
+          license="BSD",
+          packages=packages,
+          platforms='any',
+          py_modules=py_modules,
+          ext_modules=ext_modules,
+          package_dir=package_dir,
+          package_data=package_data,
+          classifiers=classifiers,
+          download_url="https://downloads.sourceforge.net/project/matplotlib/matplotlib/matplotlib-{0}/matplotlib-{0}.tar.gz".format(__version__),
+
+          # List third-party Python packages that we require
+          install_requires=install_requires,
+
+          # Automatically 2to3 source on Python 3.x
+          use_2to3=True,
+
+          # matplotlib has C/C++ extensions, so it's not zip safe.
+          # Telling setuptools this prevents it from doing an automatic
+          # check for zip safety.
+          zip_safe=False,
+
+          # Install our nose plugin so it will always be found
+          entry_points={
+              'nose.plugins.0.10': [
+                  'KnownFailure = matplotlib.testing.noseclasses:KnownFailure'
+                ]
+            },
+         )

setupext.py

@@ -723,6 +723,9 @@ class FreeType(SetupPackage):
     name = "freetype"
 
     def check(self):
+        if sys.platform == 'win32':
+            return "Unknown version"
+
         status, output = getstatusoutput("freetype-config --version")
         if status == 0:
             version = output
@@ -885,6 +888,24 @@ def get_install_requires(self):
         return ['python_dateutil']
 
 
+class Tornado(SetupPackage):
+    name = "tornado"
+
+    def check(self):
+        try:
+            import tornado
+        except ImportError:
+            return (
+                "tornado was not found. It is required for the WebAgg "
+                "backend. pip/easy_install may attempt to install it "
+                "after matplotlib.")
+
+        return "using tornado version %s" % tornado.__version__
+
+    def get_install_requires(self):
+        return ['tornado']
+
+
 class Pyparsing(SetupPackage):
     name = "pyparsing"