Sentry SDK crashes in loop if `before_send` returns `None` or crashes

[orhanhenrik]

How do you use Sentry?

Sentry Saas (sentry.io)

Version

1.17.0

Steps to Reproduce

1. Configure sentry_sdk with before_send and before_send_transaction
2. Return None or crash in before_send

Expected Result

Error is ignored

Actual Result

Sentry crashes with a keyerror in an infinite loop.

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During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/app/.venv/lib/python3.10/site-packages/sentry_sdk/integrations/wsgi.py", line 136, in __call__
    rv = self.app(
  File "/app/.venv/lib/python3.10/site-packages/django/core/handlers/wsgi.py", line 131, in __call__
    response = self.get_response(request)
  File "/app/.venv/lib/python3.10/site-packages/sentry_sdk/integrations/django/__init__.py", line 417, in sentry_patched_get_response
    rv = old_get_response(self, request)
  File "/app/.venv/lib/python3.10/site-packages/django/core/handlers/base.py", line 140, in get_response
    response = self._middleware_chain(request)
  File "/app/.venv/lib/python3.10/site-packages/django/core/handlers/exception.py", line 58, in inner
    response = response_for_exception(request, exc)
  File "/app/.venv/lib/python3.10/site-packages/django/core/handlers/exception.py", line 140, in response_for_exception
    signals.got_request_exception.send(sender=None, request=request)
  File "/app/.venv/lib/python3.10/site-packages/django/dispatch/dispatcher.py", line 176, in send
    return [
  File "/app/.venv/lib/python3.10/site-packages/django/dispatch/dispatcher.py", line 177, in <listcomp>
    (receiver, receiver(signal=self, sender=sender, **named))
  File "/app/.venv/lib/python3.10/site-packages/sentry_sdk/integrations/django/signals_handlers.py", line 66, in wrapper
    return receiver(*args, **kwargs)
  File "/app/.venv/lib/python3.10/site-packages/sentry_sdk/integrations/django/__init__.py", line 480, in _got_request_exception
    hub.capture_event(event, hint=hint)
  File "/app/.venv/lib/python3.10/site-packages/sentry_sdk/hub.py", line 338, in capture_event
    rv = client.capture_event(event, hint, scope)
  File "/app/.venv/lib/python3.10/site-packages/sentry_sdk/client.py", line 420, in capture_event
    event_opt = self._prepare_event(event, hint, scope)
  File "/app/.venv/lib/python3.10/site-packages/sentry_sdk/client.py", line 276, in _prepare_event
    if before_send_transaction is not None and event.get("type") == "transaction":
AttributeError: 'NoneType' object has no attribute 'get'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/orhan/.asdf/installs/python/3.10.10/lib/python3.10/wsgiref/handlers.py", line 137, in run
    self.result = application(self.environ, self.start_response)
  File "/app/.venv/lib/python3.10/site-packages/sentry_sdk/integrations/django/__init__.py", line 137, in sentry_patched_wsgi_handler
    return SentryWsgiMiddleware(bound_old_app, use_x_forwarded_for)(
  File "/app/.venv/lib/python3.10/site-packages/sentry_sdk/integrations/wsgi.py", line 143, in __call__
    reraise(*_capture_exception(hub))
  File "/app/.venv/lib/python3.10/site-packages/sentry_sdk/integrations/wsgi.py", line 245, in _capture_exception
    hub.capture_event(event, hint=hint)
  File "/app/.venv/lib/python3.10/site-packages/sentry_sdk/hub.py", line 338, in capture_event
    rv = client.capture_event(event, hint, scope)
  File "/app/.venv/lib/python3.10/site-packages/sentry_sdk/client.py", line 420, in capture_event
    event_opt = self._prepare_event(event, hint, scope)
  File "/app/.venv/lib/python3.10/site-packages/sentry_sdk/client.py", line 276, in _prepare_event
    if before_send_transaction is not None and event.get("type") == "transaction":
AttributeError: 'NoneType' object has no attribute 'get'

[antonpirker]

Hey @orhanhenrik !
Thanks for reporting this!
Sounds like a easy to fix bug!