[bug#52731] import: texlive: Check if Subversion is installed.

Exit with a friendlier error message instead of throwing throwing a “failed with
signal 11” error if ‘svn’ isn’t in the user’s PATH.

  $ guix import texlive getmap
  command "svn" "export" "--non-interactive" "--trust-server-cert" "-r" "59745" "svn://www.tug.org/texlive/tags/texlive-2021.3/Master/texmf-dist/doc/latex/getmap/" "/tmp/guix-directory.YgfGgo/doc/latex/getmap/" failed with signal 11

* doc/guix.texi (Invoking guix import): Mention that Subversion has be
installed.
* guix/import/texlive.scm (tlpdb->package): Check if ‘svn’ is found in PATH,
if not exit with an error message.
---
 doc/guix.texi           | 4 +++-
 guix/import/texlive.scm | 7 +++++++
 2 files changed, 10 insertions(+), 1 deletion(-)


base-commit: 87e5502d406bfb44b61f7577b241602e02a3498e

Am Mittwoch, dem 22.12.2021 um 10:01 +0100 schrieb Xinglu Chen:
> Exit with a friendlier error message instead of throwing throwing a
> “failed with
> signal 11” error if ‘svn’ isn’t in the user’s PATH.
> 
>   $ guix import texlive getmap
>   command "svn" "export" "--non-interactive" "--trust-server-cert" "-
> r" "59745"
> "svn://
> www.tug.org/texlive/tags/texlive-2021.3/Master/texmf-dist/doc/latex/getmap/
> " "/tmp/guix-directory.YgfGgo/doc/latex/getmap/" failed with signal
> 11
Shouldn't we use a guix-built svn here (as in svn-fetch)?

Am Mittwoch, der 22. Dezember 2021, um 12:50 +01, schrieb Liliana Marie Prikler:

> Am Mittwoch, dem 22.12.2021 um 10:01 +0100 schrieb Xinglu Chen:
>> Exit with a friendlier error message instead of throwing throwing a
>> “failed with
>> signal 11” error if ‘svn’ isn’t in the user’s PATH.
>> 
>>   $ guix import texlive getmap
>>   command "svn" "export" "--non-interactive" "--trust-server-cert" "-
>> r" "59745"
>> "svn://
>> www.tug.org/texlive/tags/texlive-2021.3/Master/texmf-dist/doc/latex/getmap/
>> " "/tmp/guix-directory.YgfGgo/doc/latex/getmap/" failed with signal
>> 11
> Shouldn't we use a guix-built svn here (as in svn-fetch)?

Which ‘svn-fetch’ are you referring to (there are two AFAICS)?  The
Texlive importer uses ‘download-multi-svn-to-store’, which itself uses
‘svn-fetch’ from (guix build svn), but it requires the ‘svn’ program to
be in PATH.

There is another ‘svn-fetch’ procedure, in (guix svn-download), but that
one returns a fixed-output derivation, so it can only be used if we
already know the hash (which we don’t, that’s why we are fetching the
SVN repo).

Importers that fetch a Git repo don’t need ‘git’ to be in PATH since
they use the Guile-Git bindings to libgit2.  But we don’t have Guile
bindings to SVN (or Hg, CVS, Bzr), so the program has to be installed on
the host system.

Hi,

Your patch is an improvement considering this old discussion [1].

1: <https://issues.guix.gnu.org/issue/28303#5>


On Wed, 22 Dec 2021 at 14:42, Xinglu Chen <public@yoctocell.xyz> wrote:

> Which ‘svn-fetch’ are you referring to (there are two AFAICS)?  The
> Texlive importer uses ‘download-multi-svn-to-store’, which itself uses
> ‘svn-fetch’ from (guix build svn), but it requires the ‘svn’ program to
> be in PATH.
>
> There is another ‘svn-fetch’ procedure, in (guix svn-download), but that
> one returns a fixed-output derivation, so it can only be used if we
> already know the hash (which we don’t, that’s why we are fetching the
> SVN repo).

The one in (guix svn-download) uses under the hood (guix build svn), if
I read correctly:

--8<---------------cut here---------------start------------->8---
      #~(begin
          (use-modules (guix build svn))
          (svn-fetch '#$(svn-reference-url ref)
                     '#$(svn-reference-revision ref)
                     #$output
                     #:svn-command (string-append #+svn "/bin/svn")
                     #:recursive? #$(svn-reference-recursive? ref)
                     #:user-name #$(svn-reference-user-name ref)
                     #:password #$(svn-reference-password ref)))))
--8<---------------cut here---------------end--------------->8---

Anyway. :-)

> Importers that fetch a Git repo don’t need ‘git’ to be in PATH since
> they use the Guile-Git bindings to libgit2.  But we don’t have Guile
> bindings to SVN (or Hg, CVS, Bzr), so the program has to be installed on
> the host system.

I think it is not related how the call is done, here (invoke “svn”
“export” …) and not (libsvn-export …).

In the snippet above, #+svn is transparently picked from the current
subversion package.  Maybe the bit

--8<---------------cut here---------------start------------->8---
(define (subversion-package)
  "Return the default Subversion package."
  (let ((distro (resolve-interface '(gnu packages version-control))))
    (module-ref distro 'subversion)))
--8<---------------cut here---------------end--------------->8---

could go to ’(guix build svn)’, used overthere instead of “#:key
(svn-command "svn")”; and maybe exported if needed.

WDYT?


1: <https://issues.guix.gnu.org/issue/28303#5>


Cheers,
simon

Hi,

zimoun schrieb am Mittwoch der 22. Dezember 2021 um 15:23 +01:

> Hi,
>
> Your patch is an improvement considering this old discussion [1].
>
> 1: <https://issues.guix.gnu.org/issue/28303#5>

Oh, looks like this has been a problem for a while, and I suspect that
it was the root cause of [1] too.

[1]: <https://yhetil.org/guix/87im0do5iq.fsf@yoctocell.xyz>

> On Wed, 22 Dec 2021 at 14:42, Xinglu Chen <public@yoctocell.xyz> wrote:
>
>> Which ‘svn-fetch’ are you referring to (there are two AFAICS)?  The
>> Texlive importer uses ‘download-multi-svn-to-store’, which itself uses
>> ‘svn-fetch’ from (guix build svn), but it requires the ‘svn’ program to
>> be in PATH.
>>
>> There is another ‘svn-fetch’ procedure, in (guix svn-download), but that
>> one returns a fixed-output derivation, so it can only be used if we
>> already know the hash (which we don’t, that’s why we are fetching the
>> SVN repo).
>
> The one in (guix svn-download) uses under the hood (guix build svn), if
> I read correctly:
>
> --8<---------------cut here---------------start------------->8---
>       #~(begin
>           (use-modules (guix build svn))
>           (svn-fetch '#$(svn-reference-url ref)
>                      '#$(svn-reference-revision ref)
>                      #$output
>                      #:svn-command (string-append #+svn "/bin/svn")
>                      #:recursive? #$(svn-reference-recursive? ref)
>                      #:user-name #$(svn-reference-user-name ref)
>                      #:password #$(svn-reference-password ref)))))
> --8<---------------cut here---------------end--------------->8---
>
> Anyway. :-)
>
>> Importers that fetch a Git repo don’t need ‘git’ to be in PATH since
>> they use the Guile-Git bindings to libgit2.  But we don’t have Guile
>> bindings to SVN (or Hg, CVS, Bzr), so the program has to be installed on
>> the host system.
>
> I think it is not related how the call is done, here (invoke “svn”
> “export” …) and not (libsvn-export …).

My point was that because we don’t have Guile bindings to any VCS except
Git, the user needs to have the corresponding VCS program installed in
order for the importer to fetch the repo.

> In the snippet above, #+svn is transparently picked from the current
> subversion package.  Maybe the bit
>
> --8<---------------cut here---------------start------------->8---
> (define (subversion-package)
>   "Return the default Subversion package."
>   (let ((distro (resolve-interface '(gnu packages version-control))))
>     (module-ref distro 'subversion)))
> --8<---------------cut here---------------end--------------->8---
>
> could go to ’(guix build svn)’, used overthere instead of “#:key
> (svn-command "svn")”; and maybe exported if needed.
>
> WDYT?

Sure, that sounds like a nice refactoring.  It seems to apply to the
other VCSs too.  :-)

May I raise back this issue as I lost some time understanding why I couldn't "guix import texlive ...". All I needed was subversion installed. Can this be at least documented in the manual please?