Fixed #25373 -- Added warning logging for exceptions during {% include %} tag rendering.

django/template/loader_tags.py

@@ -1,3 +1,4 @@
+import logging
 from collections import defaultdict
 
 from django.utils import six
@@ -12,6 +13,8 @@ register = Library()
 
 BLOCK_CONTEXT_KEY = 'block_context'
 
+logger = logging.getLogger('django.template')
+
 
 class ExtendsError(Exception):
     pass
@@ -207,6 +210,13 @@ class IncludeNode(Node):
         except Exception:
             if context.template.engine.debug:
                 raise
+            template_name = getattr(context, 'template_name', None) or 'unknown'
+            logger.warn(
+                "Exception raised while rendering {%% include %%} for "
+                "template '%s'. Empty string rendered instead.",
+                template_name,
+                exc_info=True,
+            )
             return ''
 
 

docs/ref/templates/builtins.txt

@@ -673,9 +673,14 @@ if it's missing or has syntax errors), the behavior varies depending on the
 :class:`template engine's <django.template.Engine>` ``debug`` option (if not
 set, this option defaults to the value of :setting:`DEBUG`). When debug mode is
 turned on, an exception like :exc:`~django.template.TemplateDoesNotExist` or
-:exc:`~django.template.TemplateSyntaxError` will be raised; otherwise
-``{% include %}`` silences any exception that happens while rendering the
-included template and returns an empty string.
+:exc:`~django.template.TemplateSyntaxError` will be raised. When debug mode
+is turned off, ``{% include %}`` logs a warning to the ``django.template``
+logger with the exception that happens while rendering the included template
+and returns an empty string.
+
+.. versionchanged:: 1.9
+
+    Template logging now includes the warning logging mentioned above.
 
 .. note::
     The :ttag:`include` tag should be considered as an implementation of

docs/releases/1.9.txt

@@ -596,8 +596,15 @@ Templates
 * Added a :meth:`Context.setdefault() <django.template.Context.setdefault>`
   method.
 
-* A warning will now be logged for missing context variables. These messages
-  will be logged to the :ref:`django.template <django-template-logger>` logger.
+* The :ref:`django.template <django-template-logger>` logger was added and
+  includes the following messages:
+
+  * A ``DEBUG`` level message for missing context variables.
+
+  * A ``WARNING`` level message for uncaught exceptions raised
+    during the rendering of an ``{% include %}`` when debug mode is off
+    (helpful since ``{% include %}`` silences the exception and returns an
+    empty string).
 
 * The :ttag:`firstof` template tag supports storing the output in a variable
   using 'as'.

tests/template_tests/test_logging.py

@@ -2,7 +2,7 @@ from __future__ import unicode_literals
 
 import logging
 
-from django.template import Engine, Variable, VariableDoesNotExist
+from django.template import Context, Engine, Variable, VariableDoesNotExist
 from django.test import SimpleTestCase
 
 
@@ -15,18 +15,22 @@ class TestHandler(logging.Handler):
         self.log_record = record
 
 
-class VariableResolveLoggingTests(SimpleTestCase):
+class BaseTemplateLoggingTestCase(SimpleTestCase):
     def setUp(self):
         self.test_handler = TestHandler()
         self.logger = logging.getLogger('django.template')
         self.original_level = self.logger.level
         self.logger.addHandler(self.test_handler)
-        self.logger.setLevel(logging.DEBUG)
+        self.logger.setLevel(self.loglevel)
 
     def tearDown(self):
         self.logger.removeHandler(self.test_handler)
         self.logger.level = self.original_level
 
+
+class VariableResolveLoggingTests(BaseTemplateLoggingTestCase):
+    loglevel = logging.DEBUG
+
     def test_log_on_variable_does_not_exist_silent(self):
         class TestObject(object):
             class SilentDoesNotExist(Exception):
@@ -78,3 +82,44 @@ class VariableResolveLoggingTests(SimpleTestCase):
     def test_no_log_when_variable_exists(self):
         Variable('article.section').resolve({'article': {'section': 'News'}})
         self.assertIsNone(self.test_handler.log_record)
+
+
+class IncludeNodeLoggingTests(BaseTemplateLoggingTestCase):
+    loglevel = logging.WARN
+
+    @classmethod
+    def setUpClass(cls):
+        super(IncludeNodeLoggingTests, cls).setUpClass()
+        cls.engine = Engine(loaders=[
+            ('django.template.loaders.locmem.Loader', {
+                'child': '{{ raises_exception }}',
+            }),
+        ], debug=False)
+
+        def error_method():
+            raise IndexError("some generic exception")
+
+        cls.ctx = Context({'raises_exception': error_method})
+
+    def test_logs_exceptions_during_rendering_with_debug_disabled(self):
+        template = self.engine.from_string('{% include "child" %}')
+        template.name = 'template_name'
+        self.assertEqual(template.render(self.ctx), '')
+        self.assertEqual(
+            self.test_handler.log_record.getMessage(),
+            "Exception raised while rendering {% include %} for template "
+            "'template_name'. Empty string rendered instead."
+        )
+        self.assertIsNotNone(self.test_handler.log_record.exc_info)
+        self.assertEqual(self.test_handler.log_record.levelno, logging.WARN)
+
+    def test_logs_exceptions_during_rendering_with_no_template_name(self):
+        template = self.engine.from_string('{% include "child" %}')
+        self.assertEqual(template.render(self.ctx), '')
+        self.assertEqual(
+            self.test_handler.log_record.getMessage(),
+            "Exception raised while rendering {% include %} for template "
+            "'unknown'. Empty string rendered instead."
+        )
+        self.assertIsNotNone(self.test_handler.log_record.exc_info)
+        self.assertEqual(self.test_handler.log_record.levelno, logging.WARN)