`download_file::tests::test_file_download_plaintext` spuriously fails about nearcore HOT 2 OPEN

I wonder if this could be down to the usage of tmp_path.persist here?

From the docs:

Note: Temporary files cannot be persisted across filesystems. Also neither the file contents nor the containing directory are synchronized, so the update may not yet have reached the disk when persist returns.

I haven't been able to replicate the error, but this would explain the test failure, where the test tries to read the file as soon as download_file has returned Ok.

It seems like there might be a couple of places in init_configs where there's an assumption the downloaded file is immediately available for reading too, so possibly download_file needs to be updated to fsync the folder somehow (not sure if that's viable) or persist changed for a more manual approach where the renamed file gets synced right away.

from nearcore.

Hm, as far as modern operating systems are concerned, the "may not have yet reached the disk" usually means that the page data may still be in page caches or a writeback queue of some sort. But the OS will consult with these structures when the data is read back to provide a consistent and sequentially ordered view of the file system(s). I believe this may refer to situations where operating system stops executing at all, whether it be a result of a crash or a power loss or a similar such scenario.

from nearcore.