Fix for partial signals in old Django and old Python versions. (#1641)

* Making sure signal names can be retrieved from partials and normal functions in all Python and Django versions. 
* Added test to safeguard the change.

sentry_sdk/integrations/django/signals_handlers.py

@@ -13,19 +13,32 @@
     from typing import List
 
 
+def _get_receiver_name(receiver):
+    # type: (Callable[..., Any]) -> str
+    name = ""
+
+    if hasattr(receiver, "__qualname__"):
+        name += receiver.__qualname__
+    elif hasattr(receiver, "__name__"):  # Python 2.7 has no __qualname__
+        name += receiver.__name__
+
+    if (
+        name == ""
+    ):  # certain functions (like partials) dont have a name so return the string representation
+        return str(receiver)
+
+    if hasattr(receiver, "__module__"):  # prepend with module, if there is one
+        name = receiver.__module__ + "." + name
+
+    return name
+
+
 def patch_signals():
     # type: () -> None
     """Patch django signal receivers to create a span"""
 
     old_live_receivers = Signal._live_receivers
 
-    def _get_receiver_name(receiver):
-        # type: (Callable[..., Any]) -> str
-        name = receiver.__module__ + "."
-        if hasattr(receiver, "__name__"):
-            return name + receiver.__name__
-        return name + str(receiver)
-
     def _sentry_live_receivers(self, sender):
         # type: (Signal, Any) -> List[Callable[..., Any]]
         hub = Hub.current
@@ -35,11 +48,12 @@ def sentry_receiver_wrapper(receiver):
             # type: (Callable[..., Any]) -> Callable[..., Any]
             def wrapper(*args, **kwargs):
                 # type: (Any, Any) -> Any
+                signal_name = _get_receiver_name(receiver)
                 with hub.start_span(
                     op="django.signals",
-                    description=_get_receiver_name(receiver),
+                    description=signal_name,
                 ) as span:
-                    span.set_data("signal", _get_receiver_name(receiver))
+                    span.set_data("signal", signal_name)
                     return receiver(*args, **kwargs)
 
             return wrapper

tests/integrations/django/test_basic.py

@@ -1,25 +1,26 @@
 from __future__ import absolute_import
 
+import json
 import pytest
 import pytest_django
-import json
+from functools import partial
 
 from werkzeug.test import Client
 from django import VERSION as DJANGO_VERSION
 from django.contrib.auth.models import User
 from django.core.management import execute_from_command_line
 from django.db.utils import OperationalError, ProgrammingError, DataError
 
-from sentry_sdk.integrations.executing import ExecutingIntegration
-
 try:
     from django.urls import reverse
 except ImportError:
     from django.core.urlresolvers import reverse
 
+from sentry_sdk._compat import PY2
 from sentry_sdk import capture_message, capture_exception, configure_scope
 from sentry_sdk.integrations.django import DjangoIntegration
-from functools import partial
+from sentry_sdk.integrations.django.signals_handlers import _get_receiver_name
+from sentry_sdk.integrations.executing import ExecutingIntegration
 
 from tests.integrations.django.myapp.wsgi import application
 
@@ -816,3 +817,22 @@ def test_custom_urlconf_middleware(
     assert "custom_urlconf_middleware" in render_span_tree(transaction_event)
 
     settings.MIDDLEWARE.pop(0)
+
+
+def test_get_receiver_name():
+    def dummy(a, b):
+        return a + b
+
+    name = _get_receiver_name(dummy)
+
+    if PY2:
+        assert name == "tests.integrations.django.test_basic.dummy"
+    else:
+        assert (
+            name
+            == "tests.integrations.django.test_basic.test_get_receiver_name.<locals>.dummy"
+        )
+
+    a_partial = partial(dummy)
+    name = _get_receiver_name(a_partial)
+    assert name == str(a_partial)