chore: Remove Koa middleware span reporting (#12501)

server/logging/tracer.ts

@@ -31,6 +31,10 @@ if (env.DD_API_KEY) {
     env: env.ENVIRONMENT,
     logInjection: true,
   });
+
+  // Disable per-middleware spans so that non-reportable errors are not captured
+  // This is also generally excessive noise
+  tracer.use("koa", { middleware: false });
 }
 
 const getCurrentSpan = (): Span | null => tracer.scope().active();

server/onerror.ts

@@ -7,7 +7,6 @@ import { escape, isNil, snakeCase } from "es-toolkit/compat";
 import env from "@server/env";
 import { ClientClosedRequestError, InternalError } from "@server/errors";
 import { requestErrorHandler } from "@server/logging/sentry";
-import { addTags, getRootSpanFromRequestContext } from "@server/logging/tracer";
 
 let errorHtmlCache: Buffer | undefined;
 
@@ -54,14 +53,6 @@ export default function onerror(app: Koa) {
         }
         err = InternalError();
       }
-    } else {
-      // Clear error tags that dd-trace's Koa plugin sets automatically
-      // when an exception propagates through middleware, so that
-      // non-reportable errors are not flagged as errors in DataDog.
-      const span = getRootSpanFromRequestContext(this);
-      if (span) {
-        addTags({ error: false }, span);
-      }
     }
 
     const headerSent = this.headerSent || !this.writable;