Nicolas Mattia

Hi! Could it be an [issue in your nix configuration](https://github.com/NixOS/nixpkgs/issues/45339)?

I see. It definitely looks like a `nix` issue (in particular `nix-prefetch-url`) more than a `niv` issue. I suggest opening a ticket [here](https://github.com/nixos/nix), they'll be able to help!

@TheOddler Right, the file `https://downloads.haskell.org/~ghc/9.0.1/ghc-9.0.1-i386-deb8-linux.tar.xz` indeed doesn't exit. The error message is a bit dramatic though, it's not really a bug, but a 404.

> What's the reason behind this? I don't remember for sure, but I think this had to do with restricted eval (where every single URL has to be whitelisted when...

The `--help` says this: ``` -t,--template URL Used during 'update' when building URL. Occurrences of are replaced with attribute 'foo'. ``` I guess something like this could be added to...

All looks correct to me too. @codygman did you figure it out? Alternatively can you share your config so that we can have a better look?

Makes sense. What about `niv update --force`?

I think the reason is that the tarball doesn't exist: ``` shell $ curl -I https://notabug.org/irdvo/gpxtools/archive/5a752894dcedf9c9a2848c5ef347121718fa98bf.tar.gz HTTP/2 404 server: nginx/1.12.1 date: Tue, 21 Jul 2020 08:55:16 GMT content-type: text/html; charset=UTF-8...

Actually, there's something really odd happening. It looks like nix-prefetch-url is given the wrong tarball (the `rev` is different in the 404 scenario). Need to investigate.

Haha, you're definitely right. Niv thinks it's a github repo and fetches the last rev from GitHub. Will need to think about how to fix this.