Re: Odd behavior with --dry-run and --upgrade

[Alex Kost <alezost@gmail.com>]

Ludovic Courtès (2016-07-28 01:19 +0300) wrote:

> Alex Kost <alezost@gmail.com> skribis:
>
>> I have zero knowledge in grafting, but if I checked it right, the
>> attached patch should disable grafting for the emacs interface (when
>> dry-run is on).  If you think it should be a part of a bigger
>> dry-run+no-grafts patch, please use it.
>
> Two separate patches is fine, IMO.

OK, then I'll commit this patch when it will be ready.

>> From d7747453bf31a616d414dce293fc0556d601abcb Mon Sep 17 00:00:00 2001
>> From: Alex Kost <alezost@gmail.com>
>> Date: Wed, 27 Jul 2016 14:55:50 +0300
>> Subject: [PATCH] emacs: Disable grafts when dry-run is enabled.
>>
>> * emacs/guix-main.scm (process-package-actions): Set grafting according
>> to 'dry-run?'.
>> * guix/scripts.scm (build-package): Likewise.
>
> [...]
>
>>  (define-module (guix scripts)
>> +  #:use-module (guix grafts)
>>    #:use-module (guix utils)
>>    #:use-module (guix ui)
>>    #:use-module (guix store)
>> @@ -106,6 +107,7 @@ true."
>>    "Build PACKAGE using BUILD-OPTIONS acceptable by 'set-build-options'.
>>  Show what and how will/would be built."
>>    (mbegin %store-monad
>> +    (set-grafting (not dry-run?))
>>      (apply set-build-options*
>>             #:use-substitutes? use-substitutes?
>>             (strip-keyword-arguments '(#:dry-run?) build-options))
>
> Here it might be best to do something like this:
>
>   (mlet %store-monad ((grafting? ((lift0 %graft? %store-monad))))
>     (set-grafting (and (not dry-run?) grafting?))
>     …)
>
> This would make sure we don’t enable grafting if it turned out to be
> disabled.
>
> WDYT?

OK, you know better :-)

However, I tried it and it doesn't work for me (note: I know nothing
about monads, gexps, etc.).  When I try this:

   (mbegin %store-monad
     (set-grafting #f)
     …)

the grafting doesn't happen, but when I try this:

   (mlet %store-monad ((grafting? ((lift0 %graft? %store-monad))))
     (set-grafting #f)
     …)

grafting happens anyway.  I have no idea what the problem is.

-- 
Alex