Fixed #18985 -- made DeprecationWarnings loud

Capture warnings in Python >= 2.7 and route through
console handler, which is subject to DEBUG==True

Thanks to dstufft for the idea, and claudep for initial patch

django/conf/__init__.py

@@ -6,6 +6,7 @@ variable, and then from django.conf.global_settings; see the global settings fil
 a list of all possible variables.
 """
 
+import logging
 import os
 import time     # Needed for Windows
 import warnings
@@ -55,6 +56,15 @@ class LazySettings(LazyObject):
         """
         Setup logging from LOGGING_CONFIG and LOGGING settings.
         """
+        try:
+            # Route warnings through python logging
+            logging.captureWarnings(True)
+            # Allow DeprecationWarnings through the warnings filters
+            warnings.simplefilter("default", DeprecationWarning)
+        except AttributeError:
+            # No captureWarnings on Python 2.6, DeprecationWarnings are on anyway
+            pass
+
         if self.LOGGING_CONFIG:
             from django.utils.log import DEFAULT_LOGGING
             # First find the logging configuration function ...

django/utils/log.py

@@ -62,6 +62,9 @@ DEFAULT_LOGGING = {
             'level': 'ERROR',
             'propagate': False,
         },
+        'py.warnings': {
+            'handlers': ['console'],
+        },
     }
 }