Prevent Falcon integration from breaking ASGI apps (#2359)

* Prevent Falcon integration from breaking ASGI apps

* Remove trailing comma

Author: szokeasaurusrex

sentry_sdk/integrations/falcon.py

@@ -206,13 +206,20 @@ def _patch_prepare_middleware():
     original_prepare_middleware = falcon_helpers.prepare_middleware
 
     def sentry_patched_prepare_middleware(
-        middleware=None, independent_middleware=False
+        middleware=None, independent_middleware=False, asgi=False
     ):
-        # type: (Any, Any) -> Any
+        # type: (Any, Any, bool) -> Any
+        if asgi:
+            # We don't support ASGI Falcon apps, so we don't patch anything here
+            return original_prepare_middleware(middleware, independent_middleware, asgi)
+
         hub = Hub.current
         integration = hub.get_integration(FalconIntegration)
         if integration is not None:
             middleware = [SentryFalconMiddleware()] + (middleware or [])
+
+        # We intentionally omit the asgi argument here, since the default is False anyways,
+        # and this way, we remain backwards-compatible with pre-3.0.0 Falcon versions.
         return original_prepare_middleware(middleware, independent_middleware)
 
     falcon_helpers.prepare_middleware = sentry_patched_prepare_middleware

tests/integrations/falcon/test_falcon.py

@@ -13,6 +13,14 @@
 from sentry_sdk.integrations.logging import LoggingIntegration
 
 
+try:
+    import falcon.asgi
+except ImportError:
+    pass
+else:
+    import falcon.inspect  # We only need this module for the ASGI test
+
+
 @pytest.fixture
 def make_app(sentry_init):
     def inner():
@@ -391,3 +399,24 @@ def generator():
 
     with sentry_sdk.configure_scope() as scope:
         assert not scope._tags["request_data"]
+
+
+@pytest.mark.skipif(
+    not hasattr(falcon, "asgi"), reason="This Falcon version lacks ASGI support."
+)
+def test_falcon_not_breaking_asgi(sentry_init):
+    """
+    This test simply verifies that the Falcon integration does not break ASGI
+    Falcon apps.
+
+    The test does not verify ASGI Falcon support, since our Falcon integration
+    currently lacks support for ASGI Falcon apps.
+    """
+    sentry_init(integrations=[FalconIntegration()])
+
+    asgi_app = falcon.asgi.App()
+
+    try:
+        falcon.inspect.inspect_app(asgi_app)
+    except TypeError:
+        pytest.fail("Falcon integration causing errors in ASGI apps.")