Flakes and remote repos not being updated

Solene · September 9, 2022, 10:44pm

Hi!

I added a flakes.nix file to my project to ease distribution, published it on GitHub, but when I run nix shell github:rapenne-s/bento, I always get the first version fetched. If I update the code on GitHub meanwhile, the nix shell command is instantaneous and still using the same version as the first time.

I don’t really understand why I get this behavior, and how to fix it.

tejing · September 9, 2022, 10:48pm

Nix caches such downloads for a fixed length of time. You can run a command with --tarball-ttl 0 or you can blow away ~/.cache/nix/.

Solene · September 9, 2022, 10:50pm

Cool! I cleaned the cache and it worked.

Do you know where this is documented? I can’t find cache related information in the man pages

tejing · September 9, 2022, 10:55pm

The only place I know it’s (partially) documented is in man nix.conf under tarball-ttl.

Solene · September 10, 2022, 8:21am

the default value is 4294967295 this seems super wrong to me, it’s 136 years. I understand flakes downloaded remotely are never updated !?

tejing · September 10, 2022, 8:29am

That can’t be right…

After a bit of searching, I think it’s actually 1 hour. The documentation must just be wrong:

github.com

NixOS/nix/blob/8d84634e26d6a09f9ca3fe71fcf9cba6e4a95107/src/libstore/globals.hh#L542

    
      
              this, {}, "secret-key-files",
              R"(
                A whitespace-separated list of files containing secret (private)
                keys. These are used to sign locally-built paths. They can be
                generated using `nix-store --generate-binary-cache-key`. The
                corresponding public key can be distributed to other users, who
                can add it to `trusted-public-keys` in their `nix.conf`.
              )"};
          
          
Setting<unsigned int> tarballTtl{
              this, 60 * 60, "tarball-ttl",
              R"(
                The number of seconds a downloaded tarball is considered fresh. If
                the cached tarball is stale, Nix will check whether it is still up
                to date using the ETag header. Nix will download a new version if
                the ETag header is unsupported, or the cached ETag doesn't match.
          
          
      Setting the TTL to `0` forces Nix to always check if the tarball is
                up to date.
          
          
      Nix caches tarballs in `$XDG_CACHE_HOME/nix/tarballs`.

Solene · September 10, 2022, 8:31am

that number looks suspiciously like the maximum of an integer

Meanwhile, i’m making a PR to add --tarball-ttl to flakes command man page

tejing · September 10, 2022, 8:31am

It is mentioned briefly in man nix.

Solene · September 10, 2022, 8:32am

yes, but I don’t see why one would go to read man.nix to look for parameters to nix shell ?

tejing · September 10, 2022, 8:33am

A lot of those options apply to all nix commands, since they override nix.conf settings. Though that’s just another of those things you “just have to know”…

Solene · September 10, 2022, 8:35am

oh, that’s particularly helpful to know!!

But yeah, this is absolutely not obvious behavior @fricklerhandwerk do you have an idea where this can be documented?

Solene · September 10, 2022, 8:40am

github.com/NixOS/nix

wrong default value 4294967295 in nix.conf man page

opened 08:40AM - 10 Sep 22 UTC

rapenne-s

bug

**Describe the bug** the `tarball-ttl` default value reported in the nix.conf… man page is wrong, in https://github.com/NixOS/nix/blob/8d84634e26d6a09f9ca3fe71fcf9cba6e4a95107/src/libstore/globals.hh#L542 the default is set to 60*60 which is 3600 but the man page has 4294967295 **Steps To Reproduce** 1. search `tarball-ttl` in nix.conf man page 2. the default is 4294967295, 3. it should be 3600 4. 4294967295 is the maximum value of an unsigned int https://en.wikipedia.org/wiki/4,294,967,295

NobbZ · September 10, 2022, 10:47am

github.com/NixOS/nix

`experimental-features` default is wrong, actual value seems to be empty

opened 10:54AM - 17 Aug 22 UTC

l0b0

bug

**Describe the bug** [The docs](https://nixos.org/manual/nix/stable/command-r…ef/conf-file.html#conf-experimental-features) say that the `experimental-features` default is `nix-command`, which does not seem to be correct: ``` $ nix fmt error: experimental Nix feature 'nix-command' is disabled; use '--extra-experimental-features nix-command' to override ``` **Steps To Reproduce** 1. Upgrade to 2.8 (aka. nixpkgs 22.05 stable) 2. Run `nix fmt` 3. Check the documentation for the error message shown above **Expected behavior** The error message should agree with the documentation. nix-env (Nix) 2.8.1

fricklerhandwerk · September 10, 2022, 11:38am

There is PR to address this discrepancy: https://github.com/NixOS/nix/pull/6854

fricklerhandwerk · September 10, 2022, 11:46am

Intuitively I would also say common options should be documented for each command that shares them, and indeed that’s what we already have in principle: nix shell

Agree with @tejing that „you just have to know“ does not scale.

One could probably make another category for common flags, and possibly that would require some new logic if it doesn’t nicely map to what’s there already.

I recently refactored the rendering part, which should now hopefully make the idea behind how that stuff is presented a bit easier to grok.

ruro · September 14, 2022, 7:50pm

See some related discussion here: nix commands shouldn't cache remote git refs · Issue #6830 · NixOS/nix · GitHub