Is generateMetadata blocked by generateViewport?

[corbin-mosher]

We are working on adopting the Next app router and have been tracing and testing our initial POC pages before migrating.

While doing so I am noticing that generateMetadata functions for us are executing after generateViewport completes. Is this expected? I would have thought they would execute in parallel and any precedence overriding would happen while merging results from each of them.

Is anyone familiar with this functionality within Next?

[corbin-mosher]

In this screenshot, the bottom group of tracing spans involve a network request to gather data about the viewport from a headless CMS. The top group of tracing spans (connected by a red line I added) are the request to gather data related to the metadata for the page.

It doesn't feel like either of these functions should require the other to complete first before processing its own data. They are both defined within the same page.tsx file.

I am also curious about the large gap circled that is a pause between our express.js server calling Next's request handler and our first lines of code in our layout.tsx and page.tsx executing.

In the page's directory traces we have, there is no gap between starting the Next request handler and our code in the App and Document components executing.