Using the Guile json module in a gexp

Using the Guile json module in a gexp

[Christopher Baines]

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Hey,

So I'm having some trouble using the Guile json module in a gexp.
I've added (with-imported-modules '((json)) ...), and the
module-import-compiled builder crashes.

Backtrace:
           4 (primitive-load "/gnu/store/35zv0m9wwd2nz3agyywv09d3k5v?")
In srfi/srfi-1.scm:
    640:9  3 (for-each #<procedure c10700 at ice-9/eval.scm:333:13 ?> ?)
In ice-9/eval.scm:
   245:16  2 (_ #(#(#<directory (guix build utils) 83f6e0> "/gn?") #))
In ice-9/boot-9.scm:
  1519:24  1 (_ "./json.scm")
In unknown file:
           0 (stat "./json.scm" #<undefined>)

ERROR: In procedure stat:
ERROR: In procedure stat: No such file or directory: "./json.scm"


The builder doesn't call stat directly, the stack trace gives line
numbers within other code, and its infeasible to add debugging mesasges
to the builder, as that requires rebuilding the world (at least with
the way I am running it).

I'll try and see if I can evaluate the same code outside of the
derivation to track down where it's calling stat, but let me know if
you can see what is going wrong.

Thanks,

Chris

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Re: Using the Guile json module in a gexp

[Ludovic Courtès]

Hello!

Christopher Baines <mail@cbaines.net> skribis:

> So I'm having some trouble using the Guile json module in a gexp.
> I've added (with-imported-modules '((json)) ...), and the
> module-import-compiled builder crashes.
>
> Backtrace:
>            4 (primitive-load "/gnu/store/35zv0m9wwd2nz3agyywv09d3k5v?")
> In srfi/srfi-1.scm:
>     640:9  3 (for-each #<procedure c10700 at ice-9/eval.scm:333:13 ?> ?)
> In ice-9/eval.scm:
>    245:16  2 (_ #(#(#<directory (guix build utils) 83f6e0> "/gn?") #))
> In ice-9/boot-9.scm:
>   1519:24  1 (_ "./json.scm")
> In unknown file:
>            0 (stat "./json.scm" #<undefined>)
>
> ERROR: In procedure stat:
> ERROR: In procedure stat: No such file or directory: "./json.scm"

This would have the effect of importing the (json) module of the host
environment into the build environment, which is not desirable for a
couple of reasons:

  1. It would require having Guile-JSON installed in the host
     environment, and the right version of it.

  2. It would hinder reproducibility since different users may have
     different Guile-JSON variants installed on the host side.

To overcome this, you have to do like (guix scripts package) does:

  #~(begin
      (add-to-load-path #$(file-append guile-json
                                       "/share/guile/site/"
                                       (effective-version)))
      …)

It would be nice to simplify this somehow, though.

HTH!

Ludo’.

Re: Using the Guile json module in a gexp

[Christopher Baines]

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On Mon, 11 Sep 2017 14:12:34 +0200
ludo@gnu.org (Ludovic Courtès) wrote:

> Hello!
> 
> Christopher Baines <mail@cbaines.net> skribis:
> 
> > So I'm having some trouble using the Guile json module in a gexp.
> > I've added (with-imported-modules '((json)) ...), and the
> > module-import-compiled builder crashes.
> >
> > Backtrace:
> >            4 (primitive-load
> > "/gnu/store/35zv0m9wwd2nz3agyywv09d3k5v?") In srfi/srfi-1.scm:
> >     640:9  3 (for-each #<procedure c10700 at
> > ice-9/eval.scm:333:13 ?> ?) In ice-9/eval.scm:
> >    245:16  2 (_ #(#(#<directory (guix build utils) 83f6e0> "/gn?")
> > #)) In ice-9/boot-9.scm:
> >   1519:24  1 (_ "./json.scm")
> > In unknown file:
> >            0 (stat "./json.scm" #<undefined>)
> >
> > ERROR: In procedure stat:
> > ERROR: In procedure stat: No such file or directory: "./json.scm"  
> 
> This would have the effect of importing the (json) module of the host
> environment into the build environment, which is not desirable for a
> couple of reasons:
> 
>   1. It would require having Guile-JSON installed in the host
>      environment, and the right version of it.
> 
>   2. It would hinder reproducibility since different users may have
>      different Guile-JSON variants installed on the host side.
> 
> To overcome this, you have to do like (guix scripts package) does:
> 
>   #~(begin
>       (add-to-load-path #$(file-append guile-json
>                                        "/share/guile/site/"
>                                        (effective-version)))
>       …)
> 
> It would be nice to simplify this somehow, though.

Awesome, thanks Ludo.

Your explaination makes lots of sense, and the approach you suggested
worked perfectly :)

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