error: input compression not recognized (private cache using zstd compression) about nix

[andrewhamon]

I don't get this issue if I switch from compression=zstd to compression=gzip and overwrite the cache. So I think it is an issue specific to using zstd with a cache.

[nixos-discourse]

This issue has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/2024-08-12-nix-team-meeting-minutes-168/50561/1

[roberth]

Discussed during aforementioned Nix maintainers meeting:

We have a test for zstd compression for a binary cache

If this were HTTP, I would ask the following. S3 should be analogous.
What does curl http(s)://your-cache.local/l59dvqj9lbm2n5agfx19hxbm2qlq4w0g.narinfo return?
It should provide you with a nar.zstd filename.
If you download that, is it in the correct file format?

Possibly related: #7712

[Mic92]

Possibly related: #7712

My PR was about http transport encoding (this is transparent to nix as curl handles it i.e. it should not appear in narinfo either), but the person here uses zstd compression on the content itself.

[andrewhamon]

If I find some time, I'll see if I can reproduce using minio. Unfortunately, my main specimen was serving production use cases and I already did the cache surgery, so I can't easily grab that info you are requesting.