Fixed #32261 -- Added error logging to Signal.send_robust().

django/dispatch/dispatcher.py

@@ -1,3 +1,4 @@
+import logging
 import threading
 import warnings
 import weakref
@@ -5,6 +6,8 @@ import weakref
 from django.utils.deprecation import RemovedInDjango40Warning
 from django.utils.inspect import func_accepts_kwargs
 
+logger = logging.getLogger('django.dispatch')
+
 
 def _make_id(target):
     if hasattr(target, '__func__'):
@@ -208,6 +211,12 @@ class Signal:
             try:
                 response = receiver(signal=self, sender=sender, **named)
             except Exception as err:
+                logger.error(
+                    'Error calling %s in Signal.send_robust() (%s)',
+                    receiver.__qualname__,
+                    err,
+                    exc_info=err,
+                )
                 responses.append((receiver, err))
             else:
                 responses.append((receiver, response))

docs/releases/3.2.txt

@@ -420,7 +420,8 @@ Serialization
 Signals
 ~~~~~~~
 
-* ...
+* :meth:`Signal.send_robust() <django.dispatch.Signal.send_robust>` now logs
+  exceptions.
 
 Templates
 ~~~~~~~~~

tests/dispatch/tests.py

@@ -165,13 +165,28 @@ class DispatcherTests(SimpleTestCase):
         def fails(val, **kwargs):
             raise ValueError('this')
         a_signal.connect(fails)
-        result = a_signal.send_robust(sender=self, val="test")
-        err = result[0][1]
-        self.assertIsInstance(err, ValueError)
-        self.assertEqual(err.args, ('this',))
-        self.assertTrue(hasattr(err, '__traceback__'))
-        self.assertIsInstance(err.__traceback__, TracebackType)
-        a_signal.disconnect(fails)
+        try:
+            with self.assertLogs('django.dispatch', 'ERROR') as cm:
+                result = a_signal.send_robust(sender=self, val='test')
+            err = result[0][1]
+            self.assertIsInstance(err, ValueError)
+            self.assertEqual(err.args, ('this',))
+            self.assertIs(hasattr(err, '__traceback__'), True)
+            self.assertIsInstance(err.__traceback__, TracebackType)
+
+            log_record = cm.records[0]
+            self.assertEqual(
+                log_record.getMessage(),
+                'Error calling '
+                'DispatcherTests.test_send_robust_fail.<locals>.fails in '
+                'Signal.send_robust() (this)',
+            )
+            self.assertIsNotNone(log_record.exc_info)
+            _, exc_value, _ = log_record.exc_info
+            self.assertIsInstance(exc_value, ValueError)
+            self.assertEqual(str(exc_value), 'this')
+        finally:
+            a_signal.disconnect(fails)
         self.assertTestIsClean(a_signal)
 
     def test_disconnection(self):