From mboxrd@z Thu Jan  1 00:00:00 1970
From: ludo@gnu.org (Ludovic =?utf-8?Q?Court=C3=A8s?=)
Subject: Re: Hwo to debug and teacking builds?
Date: Tue, 28 Mar 2017 11:52:16 +0200
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References: <58DA29EC.30008@crazy-compilers.com>
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In-Reply-To: <58DA29EC.30008@crazy-compilers.com> (Hartmut Goebel's message of
	"Tue, 28 Mar 2017 11:16:28 +0200")
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To: Hartmut Goebel <h.goebel@crazy-compilers.com>
Cc: help-guix <help-guix@gnu.org>

Howdy!

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

> when defining a new package, I often find myself spending *a lot* of
> time debugging and tweaking the build. E.g. the if the Makefile needs to
> be modified, or some test-cases adjusted.
>
> How do I "get into" the build container, so I can debug, modify files,
> rebuild and run tests there - in a closed environment (nearly) like the
> build-daemon has?

Most of the time, you don=E2=80=99t need to get into a container.  In those
cases, it=E2=80=99s enough to do:

  guix build -K foo
  # build fails=E2=80=A6
  cd /tmp/guix-build-foo.drv-0
  source ./environment-variables
  cd foo-1.2
  =E2=80=A6

In some cases (for example when you have tests that fail in the build
environment but succeed once you=E2=80=99ve followed the steps above), you
really need a container similar to that created by guix-daemon.  In that
case, do:

  guix build -K foo
  # build fails=E2=80=A6
  cd /tmp/guix-build-foo.drv-0
  guix environment -C foo --ad-hoc strace gdb
  rm /bin/sh           # to be really like in the guix-daemon environment
  source ./environment-variables
  cd foo-1.2
  $GUIX_ENVIRONMENT/bin/strace -f -o log make check
  =E2=80=A6

That would probably make a good =E2=80=9CDebugging Build Failures=E2=80=9D =
section.

Thoughts?

Ludo=E2=80=99.