setup.py: prevent clobering of DJANGO_SETTINGS_MODULE when compiling messages (fixes #20666)

setup.py

@@ -1,17 +1,18 @@
 #!/usr/bin/python
 import os
+import sys
 
 from setuptools import setup, find_packages
 from setuptools.command.install_lib import install_lib as _install_lib
 from distutils.command.build import build as _build
-from setuptools.command.sdist import sdist  as _sdist
+from setuptools.command.sdist import sdist as _sdist
 from distutils.cmd import Command
 
+
 class test(Command):
     description = 'run django tests'
     user_options = []
 
-
     def initialize_options(self):
         pass
 
@@ -39,24 +40,35 @@ class compile_translations(Command):
         pass
 
     def run(self):
-        import os
-        from django.core.management import call_command
         curdir = os.getcwd()
-        os.chdir(os.path.realpath('django_journal'))
-        call_command('compilemessages')
-        os.chdir(curdir)
+        try:
+            os.environ.pop('DJANGO_SETTINGS_MODULE', None)
+            from django.core.management import call_command
+            os.chdir(os.path.realpath('django_journal'))
+            call_command('compilemessages')
+        except ImportError:
+            print
+            sys.stderr.write('!!! Please install Django >= 1.4 to build translations')
+            print
+            print
+        finally:
+            os.chdir(curdir)
+
 
 class build(_build):
     sub_commands = [('compile_translations', None)] + _build.sub_commands
 
+
 class sdist(_sdist):
     sub_commands = [('compile_translations', None)] + _sdist.sub_commands
 
+
 class install_lib(_install_lib):
     def run(self):
         self.run_command('compile_translations')
         _install_lib.run(self)
 
+
 def get_version():
     import glob
     import re
@@ -113,5 +125,4 @@ setup(name='django-journal',
       ],
       setup_requires=[
           'django >= 1.4.2',
-      ],
-)
+      ])