Fixed #11193 -- WSGI handler not properly handling lock on error in…

Fixed #11193 -- WSGI handler not properly handling lock on error in load_middleware. Thanks to Phillip Sitbon.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@15205 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/core/handlers/wsgi.py

@@ -242,10 +242,16 @@ class WSGIHandler(base.BaseHandler):
         # settings weren't available.
         if self._request_middleware is None:
             self.initLock.acquire()
-            # Check that middleware is still uninitialised.
-            if self._request_middleware is None:
-                self.load_middleware()
-            self.initLock.release()
+            try:
+                # Check that middleware is still uninitialised.
+                if self._request_middleware is None:
+                    self.load_middleware()
+            except:
+                # Unload whatever middleware we got
+                self._request_middleware = None
+                raise
+            finally:
+                self.initLock.release()
 
         set_script_prefix(base.get_script_name(environ))
         signals.request_started.send(sender=self.__class__)

tests/regressiontests/handlers/tests.py

+from django.utils import unittest
+from django.conf import settings
+from django.core.handlers.wsgi import WSGIHandler
+
+class HandlerTests(unittest.TestCase):
+
+    def test_lock_safety(self):
+        """
+        Tests for bug #11193 (errors inside middleware shouldn't leave
+        the initLock locked).
+        """
+        # Mangle settings so the handler will fail
+        old_middleware_classes = settings.MIDDLEWARE_CLASSES
+        settings.MIDDLEWARE_CLASSES = 42
+        # Try running the handler, it will fail in load_middleware
+        handler = WSGIHandler()
+        self.assertEqual(handler.initLock.locked(), False)
+        try:
+            handler(None, None)
+        except:
+            pass
+        self.assertEqual(handler.initLock.locked(), False)
+        # Reset settings
+        settings.MIDDLEWARE_CLASSES = old_middleware_classes
+