Capture ServerBuild from factory function arg in createRequestHandler patch

Author: onurtemizkan

packages/react-router/src/server/instrumentation/reactRouter.ts

@@ -67,6 +67,16 @@ export class ReactRouterInstrumentation extends InstrumentationBase<Instrumentat
             const build = args[0];
             if (isServerBuildLike(build)) {
               setServerBuild(build);
+            } else if (typeof build === 'function') {
+              // Build arg can be a factory function (dev mode HMR). Wrap to capture resolved build.
+              const originalBuildFn = build as () => unknown;
+              args[0] = async function sentryWrappedBuildFn() {
+                const resolvedBuild = await originalBuildFn();
+                if (isServerBuildLike(resolvedBuild)) {
+                  setServerBuild(resolvedBuild);
+                }
+                return resolvedBuild;
+              };
             }
 
             const originalRequestHandler = original.apply(this, args);