Fix management command in Django 1.8.

Close #52.

I hope this does not break earlier versions.

django_assets/management/commands/assets.py

@@ -26,7 +26,6 @@
 import logging
 from optparse import make_option
 from django.conf import settings
-from django.core.management import LaxOptionParser
 from django.core.management.base import BaseCommand, CommandError
 
 from webassets.script import (CommandError as AssetCommandError,
@@ -35,6 +34,63 @@
 from django_assets.loaders import get_django_template_dirs, DjangoLoader
 
 
+try:
+    from django.core.management import LaxOptionParser
+except ImportError:
+    from optparse import OptionParser
+
+    class LaxOptionParser(OptionParser):
+        """
+        An option parser that doesn't raise any errors on unknown options.
+        This is needed because the --settings and --pythonpath options affect
+        the commands (and thus the options) that are available to the user.
+        Backported from Django 1.7.x
+        """
+        def error(self, msg):
+            pass
+
+        def print_help(self):
+            """Output nothing.
+            The lax options are included in the normal option parser, so under
+            normal usage, we don't need to print the lax options.
+            """
+            pass
+
+        def print_lax_help(self):
+            """Output the basic options available to every command.
+            This just redirects to the default print_help() behavior.
+            """
+            OptionParser.print_help(self)
+
+        def _process_args(self, largs, rargs, values):
+            """
+            Overrides OptionParser._process_args to exclusively handle default
+            options and ignore args and other options.
+            This overrides the behavior of the super class, which stop parsing
+            at the first unrecognized option.
+            """
+            while rargs:
+                arg = rargs[0]
+                try:
+                    if arg[0:2] == "--" and len(arg) > 2:
+                        # process a single long option (possibly with value(s))
+                        # the superclass code pops the arg off rargs
+                        self._process_long_opt(rargs, values)
+                    elif arg[:1] == "-" and len(arg) > 1:
+                        # process a cluster of short options (possibly with
+                        # value(s) for the last one only)
+                        # the superclass code pops the arg off rargs
+                        self._process_short_opts(rargs, values)
+                    else:
+                        # it's either a non-default option or an arg
+                        # either way, add it to the args list so we can keep
+                        # dealing with options
+                        del rargs[0]
+                        raise Exception
+                except:  # Needed because we might need to catch a SystemExit
+                    largs.append(arg)
+
+
 class Command(BaseCommand):
     option_list = BaseCommand.option_list + (
         make_option('--parse-templates', action='store_true',
@@ -51,10 +107,9 @@ def create_parser(self, prog_name, subcommand):
         # along to the webassets command.
         # Hooking into run_from_argv() would be another thing to try
         # if this turns out to be problematic.
-        return LaxOptionParser(prog=prog_name,
-            usage=self.usage(subcommand),
-            version=self.get_version(),
-            option_list=self.option_list)
+        parser = BaseCommand.create_parser(self, prog_name, subcommand)
+        parser.__class__ = LaxOptionParser
+        return parser
 
     def handle(self, *args, **options):
         # Due to the use of LaxOptionParser ``args`` now contains all