[Nix-dev] Getting started with cloned nixpkgs: multiple errors and other questions

[Jesse Haber-Kucharsky]

Thank you all very kindly for the information!

Based on your responses, this is my understanding on what I should do for a
local clone of nixpkgs:

- Set NIX_PATH="nixpkgs=/home/jhaberku/src/nixpkgs/pkgs"
- Update ~/.nix-defexpr to point to the clone. Luca, your pill #15
references that you will describe how to do this in the next edition (#16),
but I didn't see it there. I saw on
http://fluffynukeit.com/installing-essential-software-in-nixos/ that one
can just delete the contents of ~/.nix-defexpr and create a link to the
local nixpkgs:

  $ cd ~/.nix-defexpr && rm * && ln -s ~/src/nixpkgs nixpkgs

Is that right?

> If you are fine with building everything from source, there shouldn’t be
anything wrong. That’s actually the purpose of Nix/NixOS.

Great. :-)

Best,
--
Jesse

On Wed, Mar 4, 2015 at 1:03 AM, Kirill Elagin <kirelagin at gmail.com> wrote:

> On Tue, Mar 3, 2015 at 5:09 PM Jesse Haber-Kucharsky <
> jesse at haberkucharsky.com> wrote:
>
>> I cloned the master branch of github.com/nixos/nixpkgs and set my
>> NIX_PATH to point exclusively to the local checkout with "export
>> NIX_PATH=/home/jhaberku/src" (nixpkgs exist in the "nixpkgs" directory in
>> that location).
>>
>
> This way of seting `NIX_PATH` is somewhat outdated as it is not very
> useful nowadays, when nixpkgs and nixos are merged into one repo (they used
> to be in different repos). Most of the time you really want to use
> different syntax: `NIX_PATH=nixpkgs=/home/jhaberku/src/nixpkgs/pkgs` (note
> that pointing it to `pkgs` inside the repo is crucial).
>
>
>> Now, aside from nix complaining about unfree packages and packages marked
>> as bad (which I set in my ~/.nixpkgs/config.nix file as directed), I get
>> this error all the time:
>>
>>  $ NIX_PATH=/home/jhaberku/src nix-env -qa firefox
>> error: attribute ‘interpreterName’ missing, at
>> "/home/jhaberku/src/nixpkgs/pkgs/development/web/nodejs/build-node-package.nix":7:16
>>
>
> This part of Nix is a little bit complicated (and I will also take it one
> step furrther and say “messy”).
> `NIX_PATH` actually has almost no effect on `nix-env` as by default
> (unless overriden with `-f`) it takes the expression to evaluate from
> `~/.nix-defexpr` (see the “FILES” section of `man nix-env`). So unless you
> use `-f` it uses `nixpkgs` from the channel you are using.
> But nixpkgs themselves occasionally do `import <nixpkgs>` which _is_
> influenced by `NIX_PATH` (see the “ENVIRONMENT VARIABLES” section of `man
> nix-env`).
> So my best guess is that it is this mixture of different versions of
> nixpkgs that causes problems.
>
> So the rule of thumb is to use `-f` with `nix-env` whenever you want to
> test something in your local checkout. For some reason I never had problems
> using just `-f` without overriding `NIX_PATH` (even though, I believe this
> version conflict still takes place but in the opposite direction).
>
>
>> I checkout out a version of nixpkgs from many days earlier, and had no
>> such problem. This leads to me questions:
>>
>> - Was I doing things the right way? If so, is this just a bug that
>> slipped through the radar, or is the master branch regularly broken like
>> this? If this is normal for master, how does anyone get anything done if
>> nix-env refuses to do anything when a package is broken? If it's not a bug
>> (and an error in my configuration), what can I do to fix it?
>>
>
> Actually `nix-env` doesn’t refuse to work with broken packages if
> everything is set up properly. Tons of errors about broken packages and
> other weird stuff is usually a result of it being pointed to a wrong
> expression (likely, caused by incorrect `NIX_PATH` in your particular case).
>
>
>> - I'm running my NixOS installation from the nixos-unstable channel and I
>> have some system-level packages specified in /etc/nixos/configuration.nix.
>> If I somehow manage to get the master branch of nixpkgs actually working,
>> is there any reason why I shouldn't install all my user-level packages from
>> my local clone of master with "nix-env -i"? In other words, is it okay that
>> the system-wide packages are from a different channel than the user-level
>> packages?
>>
>
> If you are fine with building everything from source, there shouldn’t be
> anything wrong. That’s actually the purpose of Nix/NixOS.
>
>
>>
>> Thanks
>> _______________________________________________
>> nix-dev mailing list
>> nix-dev at lists.science.uu.nl
>> http://lists.science.uu.nl/mailman/listinfo/nix-dev
>>
>
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