Inform user at install time of minimal python requirements if not met.

Fixes: https://bugs.launchpad.net/ipython/+bug/505090

setup.py

@@ -1,234 +1,251 b''
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
 """Setup script for IPython.
 
 Under Posix environments it works like a typical setup.py script. 
 Under Windows, the command sdist is not supported, since IPython 
 requires utilities which are not available under Windows."""
 
 #-------------------------------------------------------------------------------
 #  Copyright (C) 2008  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-------------------------------------------------------------------------------
 
+#-----------------------------------------------------------------------------
+# Minimal Python version sanity check
+#-----------------------------------------------------------------------------
+
+import sys
+
+# This check is also made in IPython/__init__, don't forget to update both when
+# changing Python version requirements.
+if sys.version[0:3] < '2.5':
+    error = """\
+ERROR: 'IPython requires Python Version 2.5 or above.'
+Exiting."""
+    print >> sys.stderr, error
+    sys.exit(1)
+
+# At least we're on Python 2.5 or newer, move on.
+
 #-------------------------------------------------------------------------------
 # Imports
 #-------------------------------------------------------------------------------
 
 # Stdlib imports
 import os
 import shutil
-import sys
 
 from glob import glob
 
 # 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')
 
 from distutils.core import setup
 
+# Our own imports
 from IPython.utils.genutils import target_update
 
 from setupbase import (
     setup_args, 
     find_packages, 
     find_package_data, 
     find_scripts,
     find_data_files,
     check_for_dependencies
 )
 
 isfile = os.path.isfile
 pjoin = os.path.join
 
 #-----------------------------------------------------------------------------
 # Function definitions
 #-----------------------------------------------------------------------------
 
 def cleanup():
     """Clean up the junk left around by the build process"""
     if "develop" not in sys.argv:
         try:
             shutil.rmtree('ipython.egg-info')
         except:
             try:
                 os.unlink('ipython.egg-info')
             except:
                 pass
 
 #-------------------------------------------------------------------------------
 # Handle OS specific things
 #-------------------------------------------------------------------------------
 
 if os.name == 'posix':
     os_name = 'posix'
 elif os.name in ['nt','dos']:
     os_name = 'windows'
 else:
     print 'Unsupported operating system:',os.name
     sys.exit(1)
 
 # Under Windows, 'sdist' has not been supported.  Now that the docs build with
 # Sphinx it might work, but let's not turn it on until someone confirms that it
 # actually works.
 if os_name == 'windows' and 'sdist' in sys.argv:
     print 'The sdist command is not available under Windows.  Exiting.'
     sys.exit(1)
 
 #-------------------------------------------------------------------------------
 # Things related to the IPython documentation
 #-------------------------------------------------------------------------------
 
 # update the manuals when building a source dist
 if len(sys.argv) >= 2 and sys.argv[1] in ('sdist','bdist_rpm'):
     import textwrap
 
     # List of things to be updated. Each entry is a triplet of args for
     # target_update()
     to_update = [
                   # FIXME - Disabled for now: we need to redo an automatic way
                   # of generating the magic info inside the rst.                
                   #('docs/magic.tex',
                   #['IPython/Magic.py'],
                   #"cd doc && ./update_magic.sh" ),
 
                  ('docs/man/ipcluster.1.gz',
                   ['docs/man/ipcluster.1'],
                   'cd docs/man && gzip -9c ipcluster.1 > ipcluster.1.gz'),
 
                  ('docs/man/ipcontroller.1.gz',
                   ['docs/man/ipcontroller.1'],
                   'cd docs/man && gzip -9c ipcontroller.1 > ipcontroller.1.gz'),
 
                  ('docs/man/ipengine.1.gz',
                   ['docs/man/ipengine.1'],
                   'cd docs/man && gzip -9c ipengine.1 > ipengine.1.gz'),
 
                  ('docs/man/ipython.1.gz',
                   ['docs/man/ipython.1'],
                   'cd docs/man && gzip -9c ipython.1 > ipython.1.gz'),
 
                  ('docs/man/ipython-wx.1.gz',
                   ['docs/man/ipython-wx.1'],
                   'cd docs/man && gzip -9c ipython-wx.1 > ipython-wx.1.gz'),
 
                  ('docs/man/ipythonx.1.gz',
                   ['docs/man/ipythonx.1'],
                   'cd docs/man && gzip -9c ipythonx.1 > ipythonx.1.gz'),
 
                  ('docs/man/irunner.1.gz',
                   ['docs/man/irunner.1'],
                   'cd docs/man && gzip -9c irunner.1 > irunner.1.gz'),
 
                  ('docs/man/pycolor.1.gz',
                   ['docs/man/pycolor.1'],
                   'cd docs/man && gzip -9c pycolor.1 > pycolor.1.gz'),
                  ]
 
     # Only build the docs if sphinx is present
     try:
         import sphinx
     except ImportError:
         pass
     else:
         # The Makefile calls the do_sphinx scripts to build html and pdf, so
         # just one target is enough to cover all manual generation
 
         # First, compute all the dependencies that can force us to rebuild the
         # docs.  Start with the main release file that contains metadata
         docdeps = ['IPython/core/release.py']
         # Inculde all the reST sources
         pjoin = os.path.join
         for dirpath,dirnames,filenames in os.walk('docs/source'):
             if dirpath in ['_static','_templates']:
                 continue
             docdeps += [ pjoin(dirpath,f) for f in filenames
                          if f.endswith('.txt') ]
         # and the examples
         for dirpath,dirnames,filenames in os.walk('docs/example'):
             docdeps += [ pjoin(dirpath,f) for f in filenames
                          if not f.endswith('~') ]
         # then, make them all dependencies for the main PDF (the html will get
         # auto-generated as well).
         to_update.append(
             ('docs/dist/ipython.pdf',
              docdeps,
              "cd docs && make dist")
             )
         
     [ target_update(*t) for t in to_update ]
     
 #---------------------------------------------------------------------------
 # Find all the packages, package data, scripts and data_files
 #---------------------------------------------------------------------------
 
 packages = find_packages()
 package_data = find_package_data()
 scripts = find_scripts()
 data_files = find_data_files()
 
 #---------------------------------------------------------------------------
 # Handle dependencies and setuptools specific things
 #---------------------------------------------------------------------------
 
 # For some commands, use setuptools.  Note that we do NOT list install here!
 # If you want a setuptools-enhanced install, just run 'setupegg.py install'
 if len(set(('develop', 'sdist', 'release', 'bdist_egg', 'bdist_rpm',
            'bdist', 'bdist_dumb', 'bdist_wininst', 'install_egg_info',
            'build_sphinx', 'egg_info', 'easy_install', 'upload',
             )).intersection(sys.argv)) > 0:
     import setuptools
 
 # This dict is used for passing extra arguments that are setuptools 
 # specific to setup
 setuptools_extra_args = {}
 
 if 'setuptools' in sys.modules:
     setuptools_extra_args['zip_safe'] = False
     setuptools_extra_args['entry_points'] = {
         'console_scripts': [
             'ipython = IPython.core.ipapp:launch_new_instance',
             'pycolor = IPython.utils.PyColorize:main',
             'ipcontroller = IPython.kernel.ipcontrollerapp:launch_new_instance',
             'ipengine = IPython.kernel.ipengineapp:launch_new_instance',
             'ipcluster = IPython.kernel.ipclusterapp:launch_new_instance',
             'ipythonx = IPython.frontend.wx.ipythonx:main',
             'iptest = IPython.testing.iptest:main',
             'irunner = IPython.lib.irunner:main'
         ]
     }
     setup_args['extras_require'] = dict(
         kernel = [
             'zope.interface>=3.4.1',
             'Twisted>=8.0.1',
             'foolscap>=0.2.6'
         ],
         doc='Sphinx>=0.3',
         test='nose>=0.10.1',
         security='pyOpenSSL>=0.6'
     )
     # Allow setuptools to handle the scripts
     scripts = []
 else:
     # If we are running without setuptools, call this function which will
     # check for dependencies an inform the user what is needed.  This is
     # just to make life easy for users.
     check_for_dependencies()
 
 #---------------------------------------------------------------------------
 # Do the actual setup now
 #---------------------------------------------------------------------------
 
 setup_args['packages'] = packages
 setup_args['package_data'] = package_data
 setup_args['scripts'] = scripts
 setup_args['data_files'] = data_files
 setup_args.update(setuptools_extra_args)
 
 
 if __name__ == '__main__':
     setup(**setup_args)
     cleanup()