Compatibility between Nix and Guix

Compatibility between Nix and Guix

[Daniel Schäfer]

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Hi all,

I've been using NixOS for a few years and now I want to try out Guix.
The goal is to see whether there is a benefit to using both and what we can learn from each other.

Last year Ludo wrote:
> > Is compatibility with the nix-daemon a goal of the Guix project?
> 
> I’ve come to the conclusion that it’s not a worthy goal, as in, it would
> cost more than it’s worth.  guix-daemon is already incompatible with
> nix-daemon on a few things, such as the “builtin:download” derivation
> builder.

But the Guix manual at 2.2 [1] says:
> When a working installation of the Nix package manager is available, you can
> instead configure Guix with --disable-daemon. In that case, Nix replaces the
> three dependencies above.
> 
> Guix is compatible with Nix, so it is possible to share the same store between
> both. To do so, you must pass configure not only the same --with-store-dir
> value, but also the same --localstatedir value. The latter is essential because
> it specifies where the database that stores metadata about the store is
> located, among other things. The default values for Nix are
> --with-store-dir=/nix/store and --localstatedir=/nix/var. Note that
> --disable-daemon is not required if your goal is to share the store with Nix. 

How much of that is still true? The daemon is not compatible anymore and
I don't think it is a good idea to have two different daemons share the same store.

Is there still the a possibility to use either Nix on GuixSD or Guix on NixOS
without duplicating the store or running two daemons?
Or e.g. use Nix with Guile?

Cheers,
Daniel

[1] https://guix.gnu.org/manual/en/guix.html#Requirements


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Re: Compatibility between Nix and Guix

[Pjotr Prins]

Hi Daniel,

Nix and Guix are quite different even though they share the same root.
I used Nix for 10-odd years until I discovered GNU Guix.

On Thu, Sep 26, 2019 at 04:13:05AM +0200, Daniel Schäfer wrote:
> How much of that is still true? The daemon is not compatible anymore and
> I don't think it is a good idea to have two different daemons share the same sto
> re.

Correct. There are two databases and the hashes are different anyway.
No gain and plenty of potential pain.

> Is there still the a possibility to use either Nix on GuixSD or Guix on NixOS
> without duplicating the store or running two daemons?
> Or e.g. use Nix with Guile?

It is safe to use two stores and two daemons. Virtue of isolation :)

Pj.

Re: Compatibility between Nix and Guix

[Tobias Geerinckx-Rice via Development of GNU Guix and the GNU System distribution.]

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Pjotr Prins 写道：
> It is safe[r?] to use two stores and two daemons. Virtue of 
> isolation :)

I agree.  There is no advantage to sharing the store that I can 
imagine is worth the risk and burden of compiling your entire Guix 
or Nix world from scratch because you can't use substitutes.

The Guix manual says:
> Guix is compatible with Nix, so it is possible to share the same 
> store between
> both. To do so, you must pass configure not only the same 
> --with-store-dir
> value, but also the same --localstatedir value. The latter is 
> essential because
> it specifies where the database that stores metadata about the 
> store is
> located, among other things. The default values for Nix are
> --with-store-dir=/nix/store and --localstatedir=/nix/var. Note 
> that
> --disable-daemon is not required if your goal is to share the 
> store with Nix.

Unless somebody objects, I'd like to (wait for it) nix this from 
the manual entirely.

It may or may not be true still, and even if it is, it's nothing 
more than a random Fun Fact that doesn't warrant encouragement in 
official documentation.

Going once,

T G-R

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Re: Compatibility between Nix and Guix

[Ricardo Wurmus]

Tobias Geerinckx-Rice via Development of GNU Guix and the GNU System distribution. <guix-devel@gnu.org> writes:

> The Guix manual says:
>> Guix is compatible with Nix, so it is possible to share the same
>> store between
>> both. To do so, you must pass configure not only the same
>> --with-store-dir
>> value, but also the same --localstatedir value. The latter is
>> essential because
>> it specifies where the database that stores metadata about the store
>> is
>> located, among other things. The default values for Nix are
>> --with-store-dir=/nix/store and --localstatedir=/nix/var. Note that
>> --disable-daemon is not required if your goal is to share the store
>> with Nix.
>
> Unless somebody objects, I'd like to (wait for it) nix this from the
> manual entirely.

I don’t object to removing it.  In fact, I’d be happy to see it vanish.

--
Ricardo

Re: Compatibility between Nix and Guix

[Tobias Geerinckx-Rice]

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Ricardo Wurmus 写道：
> Tobias Geerinckx-Rice writes:
>> The Guix manual says:
>>> Guix is compatible with Nix, so it is possible to share […]
>>
>> Unless somebody objects, I'd like to (wait for it) nix this 
>> from the
>> manual entirely.
>
> I don’t object to removing it.  In fact, I’d be happy to see it 
> vanish.

Gone in 348d8e446fbc8f5c9a51a081047de72d735a2a8a.

Kind regards,

T G-R

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Re: Compatibility between Nix and Guix

[Ludovic Courtès]

Tobias Geerinckx-Rice <me@tobias.gr> skribis:

> Ricardo Wurmus 写道：
>> Tobias Geerinckx-Rice writes:
>>> The Guix manual says:
>>>> Guix is compatible with Nix, so it is possible to share […]
>>>
>>> Unless somebody objects, I'd like to (wait for it) nix this from
>>> the
>>> manual entirely.
>>
>> I don’t object to removing it.  In fact, I’d be happy to see it
>> vanish.
>
> Gone in 348d8e446fbc8f5c9a51a081047de72d735a2a8a.

Thanks!  I think that paragraph had been incorrect for some time indeed.

Ludo’.