Man pages are not installed with Nix 2.26.1

[hja3]

Platform

• Linux: OpenMandriva
• macOS
• WSL

Additional information

Performed a multi-user installation the usual way (i.e. via https://nixos.org/download/), which completed without error. After installation, however, I discovered that the man pages for the nix- utilities are unavailable.

Output

Output

[user@laptop ~]$ nix-env --version
nix-env (Nix) 2.26.1
[user@laptop ~]$ nix-env --help
No manual entry for nix-env
[user@laptop ~]$ ls -al /nix/var/nix/profiles/default/share/
total 0
dr-xr-xr-x 1 user user 44 Jan  1  1970 .
dr-xr-xr-x 1 user user 42 Jan  1  1970 ..
dr-xr-xr-x 1 user user 22 Jan  1  1970 bash-completion
dr-xr-xr-x 1 user user 40 Jan  1  1970 fish
dr-xr-xr-x 1 user user 28 Jan  1  1970 zsh

As shown in the output above, the nix-env --help command fails and the man directory in the default profile is absent.

Checklist

• checked latest Nix manual (source)
• checked open installer issues and pull requests for possible duplicates

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[devatbosch]

Hi @hja3 ,

I would like to take a look on this issue, Could you please share, If there is something else I also need to take care while reproducing this issue at my end?

Meanwhile let me try...

[abathur]

What does echo $MANPATH report? Does it work if you run MANPATH= man nix?

[hja3]

MANPATH is empty

[user@laptop ~]$ echo $MANPATH

The manpath command produces the following output

[user@laptop ~]$ manpath
/home/user/.nix-profile/share/man:/usr/local/share/man:/usr/share/man

Man pages for programs installed into my personal nix profile work as they should.

Trying out the command you suggest did not appear to work

[user@laptop ~]$ MANPATH= man nix
No manual entry for nix
[user@laptop ~]$ MANPATH=man nix
error: no subcommand specified
Try 'nix --help' for more information.

Switching over to root's profile, on 2.26.1 I get the following output

[root@laptop user]# nix-env --version
nix-env (Nix) 2.26.1
[root@laptop user]# manpath
/usr/share/man:/usr/local/share/man
[root@laptop user]# nix-env --help
No manual entry for nix-env

Switching profiles to a generation with nix 2.24.12 installed, results in the following

[root@laptop user]# nix-env --switch-generation 6
switching profile from version 1 to 6
[root@laptop user]# nix-env --version
nix-env (Nix) 2.24.12
[root@laptop user]# manpath
/root/.nix-profile/share/man:/nix/var/nix/profiles/default/share/man:/usr/share/man:/usr/local/share/man
[root@laptop user]# nix-env --help
nix‐env(1)                                 General Commands Manual                                 nix‐env(1)

Name
       nix‐env ‐ manipulate or query Nix user environments

Synopsis
       nix‐env  operation  [options]  [arguments…]  [‐‐option  name  value] [‐‐arg name value] [‐‐argstr name
       value] [{‐‐file | ‐f} path] [{‐‐profile | ‐p} path] [‐‐system‐filter system] [‐‐dry‐run]
...

Everying works as it should.

Finally, from my user account, on 2.24.12, I get the following output

[user@laptop ~]$ nix-env --version
nix-env (Nix) 2.24.12
[user@laptop ~]$ manpath
/home/user/.nix-profile/share/man:/nix/var/nix/profiles/default/share/man:/usr/local/share/man:/usr/share/man
[user@laptop ~]$ nix-env --help
nix‐env(1)                                 General Commands Manual                                 nix‐env(1)

Name
       nix‐env ‐ manipulate or query Nix user environments
...

It has properly configured both the user profile and default profile man paths, and everything works as it should.

As far as I can tell, the problem is that the man pages for 2.26.1 are simply absent.

[hja3]

While man pages for nix- commands does not appear to be available on 2.26.1, documentation for the experimental nix command does seem to work. Both nix --help and nix env --help display the documentation pages they ought to, for example.

[abathur]

I skimmed through everything that's touched the installer since 2.24.12 and don't see anything that seems like it would cause trouble, so I'm tentatively removing the installer label.

That plus the fact that it works with profile containing 2.24.12 makes me think this may be something shifting in Nix itself.

@hja3 Can you poke around in your store to see if the files are in the documentation output? Maybe find /nix/store/ -maxdepth 1 -name "*nix-2.26.1-man" and then run find again on the path it prints. (My hunch is that you'll find the nix3-* files there, and not the plain nix-* variants.)

@Ericson2314 Could this have fallen between the cracks in the move to meson?

[hja3]

[user@laptop ~]$ find /nix/store/ -maxdepth 1 -name "*nix-2.26.1-man"

produced no output.

Make the wildcard a little wilder and we find that only the man pages from 2.24 are available

[user@laptop ~]$ find /nix/store/ -maxdepth 1 -name "*nix*man"
/nix/store/mn5f662mp2j3mwh4ijhnh47zhf7gskx4-nix-2.24.11-man
/nix/store/4mi524538qg1056yfkp4f5y7rscpj1ys-nix-2.24.12-man

For the nix3 documentation, nix --help works, but man nix does not. Only thing I can think of is perhaps nix --help uses its own renderer? It does not display the standard man page header and the heading colours differ from regular man pages.

[arianvp]

this doesn't work on MacOS either.

[arianvp]

We should not install nix 2.26 by default if it doesn't come with any docs. Can we yoink the release for now and default to 2.25 ?

[arianvp]

the weird thing is; if you do nix shell nixpkgs#nix then the man page does start working.

It seems that the man output for whatever reason isn't installed to /nix/var/nix/profiles/default anymore -- so I do actually suspect an installer bug?

[arianvp]

old-style commands are completely broken by the way; as they defer to man for their docs. e.g. nix-env --help doesn't work

[arianvp]

https://releases.nixos.org/nix/nix-2.26.1/nix-2.26.1-aarch64-darwin.tar.xz doesn't contain any man pages in its nix store

https://releases.nixos.org/nix/nix-2.25.5/nix-2.25.5-aarch64-darwin.tar.xz does contain man pages but they are in the out output.

Meanwhile nix-2.25 from nixpkgs has the man pages in the man output. Weird discrepancy . Seems the releases are generated from a different derivation than nixpkgs.nix and this one doesn't have multiple outputs.

Something in the release process changes in such a way that man pages are not included anymore.

[arianvp]

I don't know if it's related but the documentation for nix 2.26 is also missing from https://nix.dev

[nixos-discourse]

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

https://discourse.nixos.org/t/nix-2-26-released/59211/18