Merge pull request #5374 from hypothesis/fix-exception-capture

Fix Sentry reporting in `h.util.view.handle_exception`

h/util/view.py

@@ -2,9 +2,16 @@
 
 from __future__ import unicode_literals
 
+import sys
+
 from pyramid.view import view_config
 
 
+# Test seam. Patching `sys.exc_info` directly causes problems with pytest.
+def _exc_info():
+    return sys.exc_info()
+
+
 def handle_exception(request, exception):
     """
     Handle an uncaught exception for the passed request.
@@ -13,7 +20,20 @@ def handle_exception(request, exception):
     :param exception: The exception passed as context to the exception-handling view.
     """
     request.response.status_int = 500
-    request.sentry.captureException(exception)
+
+    # There are two code paths here depending on whether this is the most recent
+    # exception in the current thread. If it is, we can let Raven capture
+    # the details under Python 2 + 3. If not, we need to construct the
+    # exc_info tuple manually and the stacktrace is only available in Python 3.
+    last_exc_info = _exc_info()
+    if exception is last_exc_info[1]:
+        request.sentry.captureException()
+    else:
+        # `__traceback__` is a Python 3-only property.
+        traceback = getattr(exception, '__traceback__', None)
+        exc_info = (type(exception), exception, traceback)
+        request.sentry.captureException(exc_info)
+
     # In debug mode we should just reraise, so that the exception is caught by
     # the debug toolbar.
     if request.debug:

tests/h/util/view_test.py

@@ -8,17 +8,27 @@
 from h.util.view import handle_exception, json_view
 
 
+@pytest.mark.usefixtures("sys_exc_info")
 class TestHandleException(object):
     def test_sets_response_status_500(self, pyramid_request):
         handle_exception(pyramid_request, Mock())
 
         assert pyramid_request.response.status_int == 500
 
-    def test_triggers_sentry_capture(self, pyramid_request):
-        exception = Mock()
-        handle_exception(pyramid_request, exception)
-
-        pyramid_request.sentry.captureException.assert_called_once_with(exception)
+    def test_triggers_sentry_capture_with_latest_exception(
+        self, pyramid_request, latest_exception
+    ):
+        handle_exception(pyramid_request, latest_exception)
+        pyramid_request.sentry.captureException.assert_called_once_with()
+
+    def test_triggers_sentry_capture_with_old_exception(
+        self, pyramid_request, old_exception
+    ):
+        handle_exception(pyramid_request, old_exception)
+        traceback = getattr(old_exception, "__traceback__", None)
+        pyramid_request.sentry.captureException.assert_called_once_with(
+            (type(old_exception), old_exception, traceback)
+        )
 
     def test_reraises_in_debug_mode(self, pyramid_request):
         pyramid_request.debug = True
@@ -38,6 +48,25 @@ def pyramid_request(self, pyramid_request):
         pyramid_request.debug = False
         return pyramid_request
 
+    @pytest.fixture
+    def latest_exception(self):
+        return Exception("Last exception raised in thread")
+
+    @pytest.fixture
+    def old_exception(self):
+        try:
+            # Create exception and populate `__traceback__` in Python 3.
+            raise Exception("An earlier exception raised in thread")
+        except Exception as exc:
+            result = exc
+        return result
+
+    @pytest.fixture
+    def sys_exc_info(self, patch, latest_exception):
+        sys_exc_info = patch("h.util.view._exc_info")
+        sys_exc_info.return_value = (type(latest_exception), latest_exception, None)
+        return sys_exc_info
+
 
 @pytest.mark.usefixtures('view_config')
 class TestJsonView(object):

tox.ini

@@ -40,6 +40,7 @@ passenv =
     CONFIG_URI
     MODEL_CREATE_ALL
     SEARCH_AUTOCONFIG
+    SENTRY_DSN
     USE_HTTPS
     WEBSOCKET_URL
 whitelist_externals = sh