[bug#50960] [PATCH 00/10] Add 'guix shell' to subsume 'guix environment'

[Christine Lemmer-Webber <cwebber@dustycloud.org>]

Ludovic Courtès <ludo@gnu.org> writes:

> Hello Guix!
>
> Here comes ‘guix shell’, a proposed replacement for ‘guix environment’!
> ‘guix environment’ would stay around though, at least for some time,
> probably for a long time.
>
> The differences to ‘guix environment’ are:
>
>   1. ‘--ad-hoc’ is the default.
>
>        ‘guix shell hello’ ≍ ‘guix environment --ad-hoc hello’
>        ‘guix shell -D hello git’ ≍ ‘guix environment hello --ad-hoc git’
>
>   2. ‘guix shell’, without arguments, loads ‘guix.scm’ or ‘manifest.scm’
>      from the current directory or one of its ancestors.
>
>   3. ‘--load’/‘-l’ is not ‘-f’/‘--install-from-file’ for consistency with
>      ‘guix package’.
>
>   4. ‘guix shell’ without arguments maintains a cache, such that, the
>      second time you run it, it runs in ~0.1s (it does not even need to
>      connect to the daemon).
>
>      If you run ‘guix pull’ and run again ‘guix shell’, it recomputes
>      the environment, as is currently the case with ‘guix environment’.
>
> Here’s a summary of previous proposals:
>
>   - Dave Thompson: https://lists.gnu.org/archive/html/guix-devel/2017-08/msg00300.html
>     - [X] --ad-hoc is the default
>     - [X] caching
>     - [X] behavior with no arguments
>     - [ ] --load accepts <environment>
>     - [ ] Shepherd services
>     - [ ] 'guix environment --update' to explicitly update
>   - make --ad-hoc the default: https://issues.guix.gnu.org/38529
>     - [X] https://issues.guix.gnu.org/38529#17: proposal for a new subcommand
>           deprecation of ‘guix environment’
>
> I think <environment> records and Shepherd services could come later.
> As for ‘--update’, I prefer the behavior implemented here because it’s
> stateless and thus more predictable.
>
> Thoughts?  Are there other changes people would like to see?
>
> If there’s rough consensus I can work on v2 with documentation.  Please
> let’s keep the discussion focused.  :-)

You have my massive thumbs up.  Exciting stuff.

> As for deprecation, I think there’s no rush.  I imagine there could be
> several phases, like: initially we only mention deprecation in the manual,
> later on ‘guix environment’ starts emitting a warning, and later (I guess
> at least two years later, probably more) we ask ourselves whether to
> remove ‘guix environment’.  At this point keeping it doesn’t cost us much.
>
> Thanks,
> Ludo’.
>
> Ludovic Courtès (10):
>   packages: Add 'package-development-inputs'.
>   profiles: Add 'package->development-manifest'.
>   DRAFT Add 'guix shell'.
>   DRAFT shell: By default load the local 'guix.scm' or 'manifest.scm'
>     file.
>   environment: Add tests for '--profile'.
>   environment: Skip derivation computation when '--profile' is used.
>   environment: Do not connect to the daemon when '--profile' is used.
>   environment: Autoload some modules.
>   cache: Gracefully handle non-existent cache.
>   shell: Maintain a profile cache.
>
>  Makefile.am                         |   2 +
>  doc/guix.texi                       |  52 ++++++
>  guix/cache.scm                      |  10 +-
>  guix/packages.scm                   |  10 ++
>  guix/profiles.scm                   |  19 ++
>  guix/scripts/environment.scm        | 260 +++++++++++++++-------------
>  guix/scripts/shell.scm              | 254 +++++++++++++++++++++++++++
>  po/guix/POTFILES.in                 |   1 +
>  tests/guix-environment-container.sh |   8 +
>  tests/guix-environment.sh           |   7 +
>  tests/guix-shell.sh                 |  70 ++++++++
>  tests/packages.scm                  |  14 ++
>  tests/profiles.scm                  |   7 +
>  13 files changed, 594 insertions(+), 120 deletions(-)
>  create mode 100644 guix/scripts/shell.scm
>  create mode 100644 tests/guix-shell.sh