Fix FastAPI/Starlette middleware with positional arguments. (#4118)

Fixes #3246

Author: antonpirker

sentry_sdk/integrations/starlette.py

@@ -362,13 +362,13 @@ def patch_middlewares():
 
     if not_yet_patched:
 
-        def _sentry_middleware_init(self, cls, **options):
-            # type: (Any, Any, Any) -> None
+        def _sentry_middleware_init(self, cls, *args, **kwargs):
+            # type: (Any, Any, Any, Any) -> None
             if cls == SentryAsgiMiddleware:
-                return old_middleware_init(self, cls, **options)
+                return old_middleware_init(self, cls, *args, **kwargs)
 
             span_enabled_cls = _enable_span_for_middleware(cls)
-            old_middleware_init(self, span_enabled_cls, **options)
+            old_middleware_init(self, span_enabled_cls, *args, **kwargs)
 
             if cls == AuthenticationMiddleware:
                 patch_authentication_middleware(cls)

tests/integrations/starlette/test_starlette.py

@@ -31,7 +31,6 @@
 from starlette.middleware.authentication import AuthenticationMiddleware
 from starlette.middleware.trustedhost import TrustedHostMiddleware
 from starlette.testclient import TestClient
-
 from tests.integrations.conftest import parametrize_test_configurable_status_codes
 
 
@@ -238,6 +237,12 @@ async def do_stuff(message):
         await self.app(scope, receive, do_stuff)
 
 
+class SampleMiddlewareWithArgs(Middleware):
+    def __init__(self, app, bla=None):
+        self.app = app
+        self.bla = bla
+
+
 class SampleReceiveSendMiddleware:
     def __init__(self, app):
         self.app = app
@@ -862,6 +867,22 @@ def test_middleware_partial_receive_send(sentry_init, capture_events):
         idx += 1
 
 
+@pytest.mark.skipif(
+    STARLETTE_VERSION < (0, 35),
+    reason="Positional args for middleware have been introduced in Starlette >= 0.35",
+)
+def test_middleware_positional_args(sentry_init):
+    sentry_init(
+        traces_sample_rate=1.0,
+        integrations=[StarletteIntegration()],
+    )
+    _ = starlette_app_factory(middleware=[Middleware(SampleMiddlewareWithArgs, "bla")])
+
+    # Only creating the App with an Middleware with args
+    # should not raise an error
+    # So as long as test passes, we are good
+
+
 def test_legacy_setup(
     sentry_init,
     capture_events,