fix(codecov): Add back needed code

Author: calvin-codecov

src/sentry/middleware/integrations/parsers/github.py

@@ -8,20 +8,23 @@
 from django.http import HttpRequest, HttpResponse
 from django.http.response import HttpResponseBase
 
+import sentry.options as options
 from sentry.hybridcloud.outbox.category import WebhookProviderIdentifier
 from sentry.integrations.github.webhook import (
     GitHubIntegrationsWebhookEndpoint,
     get_github_external_id,
 )
 from sentry.integrations.github.webhook_types import (
     GITHUB_WEBHOOK_TYPE_HEADER,
+    REGION_PROCESSED_GITHUB_EVENTS,
     GithubWebhookType,
 )
 from sentry.integrations.middleware.hybrid_cloud.parser import BaseRequestParser
 from sentry.integrations.models.integration import Integration
 from sentry.integrations.services.integration.model import RpcIntegration
 from sentry.integrations.types import IntegrationProviderSlug
 from sentry.silo.base import control_silo_function
+from sentry.utils import metrics
 
 logger = logging.getLogger(__name__)
 
@@ -115,6 +118,22 @@ def get_response(self) -> HttpResponseBase:
         if len(regions) == 0:
             return self.get_default_missing_integration_response()
 
+        github_event = self.request.META.get(GITHUB_WEBHOOK_TYPE_HEADER)
+
+        # Only drop when we have a known unprocessed event type. Missing or empty
+        # X-GitHub-Event is malformed; let the request be forwarded so the region
+        # returns 400 and GitHub is notified of the delivery failure.
+        if (
+            github_event
+            and github_event not in REGION_PROCESSED_GITHUB_EVENTS
+            and options.get("github.webhook.drop-unprocessed-events.enabled")
+        ):
+            metrics.incr(
+                "github.webhook.drop_unprocessed_event",
+                tags={"event_type": github_event or "unknown"},
+            )
+            return HttpResponse(status=202)
+
         response = self.get_response_from_webhookpayload(
             regions=regions,
             identifier=self.get_mailbox_identifier(integration, event),