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From: =?utf-8?Q?Ludovic_Court=C3=A8s?= <ludo@gnu.org>
Subject: Re: How to reference external program used in shell-scripts?
Date: Tue, 03 Sep 2019 15:01:25 +0200
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 (Hartmut Goebel's message of "Tue, 3 Sep 2019 11:08:17 +0200")
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To: Hartmut Goebel <h.goebel@crazy-compilers.com>
Cc: guix-devel@gnu.org

Hello Hartmut,

Hartmut Goebel <h.goebel@crazy-compilers.com> skribis:

> My concerns are not about building, but about installing. A concrete
> example:
>
>   * Ansible is a Python program running ssh via a path to
>     /gnu/store/=E2=80=A6-openssh-8.0p1/bin/ssh
>   * Mary installs ansible.
>   * Now openssh shows a serious bug and Mary updates openssh using "guix
>     -u openssh"
>
> Obviously this will *not* update ansible, and ansible will still use the
> old, vulnerable version of openssh.
>
> OTOH, if ansible would run ssh via $PATH, ansible would pick up the new
> version of openssh.

The whole idea of functional software deployment is that it=E2=80=99s state=
less:
you can tell that /gnu/store/=E2=80=A6-ansible-1.2.3 will always behave the
same, no matter what other programs are available on your machine.

Introducing =E2=80=9Cdynamic binding=E2=80=9D (e.g., looking up programs in=
 $PATH) would
allow for faster security updates in the example you gave, but that
would be at the expense of that core property I described above.  It
would be a regression.

I think what we need in this case is (1) fast security updates, which is
what grafts help us achieve, and (2) documentation that clarifies what
the deployment model is, such that Mary would know that =E2=80=98ansible=E2=
=80=99 also
needs to be upgraded in the example above.

Ludo=E2=80=99.