So we're seeing an issue where Next appears to be caching A LOT of data seemingly indefinitely, and it appears to cache it regardless of any Cache-Control settings.

We have an endpoint /internal/jobs/[jobId]/run which when investigating a memory leak and looking at the heap snapshots, we noticed an insane growth in strings which are just base64 representations of the data returned by this endpoint (and traversing the tree for these strings shows that they originate from this endpoint). They appear to be being cached by the IncrementalCache in the FileSystemCache under the LRUCache as Entry's, and they don't seem to ever clear out of here.

I noticed that locally when developing, we were also seeing similar entries being cached to /.next/cache/fetch-cache so it immediately made me think that this caching was causing the memory leak. I tried adding Cache-Control: no-store, no-cache, max-age=0 to the only place this endpoint gets called (it gets called very frequently, so this is a major memory leak), but it didn't seem to stop the cache files from being created locally in /.next/cache/fetch-cache, so it didn't seem to be respecting the cache-control. But then I realized that if I placed the route within an api folder (/internal/api/jobs/[jobId]/run), then locally it stops this cache file from being created when I hit this endpoint. I thought this was going to be the solution to this leak, but after deploying and monitoring the heap snapshots and memory usage, we're still seeing the same problem, so it seems like this cache is still storing all of the return data from this endpoint.

I'm not sure if this is a bug or there is something that I am missing about how to prevent this endpoint from caching? Is anyone familiar with Next's usage of the IncrementalCache, FileSystemCache or LRUCache and how to get it to flush/clear out or just not cache certain endpoints?