guix environment: add option to download and unpack source

I've a minor feature request.

When working on new package definitions, it's often useful to debug

build failures with guix environment.

The current implementation, as I understand it, requires manually

downloading the source, and merely drops you into whatever working

directory you happen to be it.

It would be great if there were an option you could pass that downloads

and unpacks the source somewhere and drops you into the newly unpacked

source directory.

Not sure what to call it exactly, but something like:

guix environment --with-source hello

Should drop you into an unpacked source directory with the inputs and

such for building "hello".

live well,

vagrant

On Sun, 24 Jun 2018 12:06:17 -0700

Vagrant Cascadian <vagrant@debian.org> wrote:

Hi Vagrant,

if you need this in the case of build failures, use the "-K" option:

--keep-failed

-K

Keep the build tree of failed builds. Thus, if a build fails, its

build tree is kept under /tmp, in a directory whose name is shown at

the end of the build log. This is useful when debugging build issues.

See Debugging Build Failures, for tips and tricks on how to debug build

issues.

See also

For the case that the built went through OK, there is no such option.

You could raise an exception at the end of your package

definition/build phases.

Also there is the -S option to build:

guix build -S <package-name>

builds the source of your package. This will download the package,

verifies the checkum applies patches and applies snippets (i.e. rules

to remove for example binaries or other non-free-licensed parts).

Björn

Hi Vagrant,

On Sun, 24 Jun 2018 12:06:17 -0700

Vagrant Cascadian <vagrant@debian.org> wrote:

+1

Right now, my silly workaround is to add a phase which fails

(add-after 'unpack 'fail

(lambda _

(error "stop it")))

and then do

guix build --keep-failed hello

and then do

guix environment --pure hello

cd /tmp/guix-build-hello*

That's... very manual.

Also, if the directory in /tmp is not .drv-0, the environment is technically not the same as it was inside the guix-daemon build container.

In that case there'd be an extra step

rm -rf /tmp/guix-build-hello-*.drv-0

ln -s /tmp/guix-build-hello-* /tmp/guix-build-hello-<...>.drv-0

cd /tmp/guix-build-hello-<...>.drv-0

All in all that's not simple.

Also, guix-daemon is taken from Nix and thus not exactly the same as

guix environment in some cases.

That's why in some cases I have to (edit the package definition and

invoke guix build) over and over again in order to find a problem.

In the long term we'll replace guix-daemon by guix environment.

Much easier to reproduce situations then.

Danny Milosavljevic writes:

A very nice recipe...interesting we had a discussion about this today on

#guix. What I would really like, is for the --with-source directory

be a git archive, so that edits can be made and tested until it works.

Attempt a rebuild with new patches/new git commit and repeat.

Making repeated patches until a build succeeds is something I find

pretty cumbersome.

It could be an ad-hoc, new git archive. It would also be nice if Guix

could somehow record upstream sources as (shallow?, tarred?) git

archives.

janneke

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Jan Nieuwenhuizen <janneke@gnu.org> | GNU LilyPond http://lilypond.org

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