Package: guix-patches;
Reported by: Simon Tournier <zimon.toutoune <at> gmail.com>
Date: Thu, 17 Aug 2023 14:08:02 UTC
Severity: normal
Done: Simon Tournier <zimon.toutoune <at> gmail.com>
Bug is archived. No further changes may be made.
Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):
From: Simon Tournier <zimon.toutoune <at> gmail.com> To: guix-patches <at> gnu.org Subject: Fix time-machine and network Date: Thu, 17 Aug 2023 16:06:50 +0200
Hi,
As discussed in patch#64746, here the fix. :-)
-------------------- Start of forwarded message --------------------
From: Maxim Cournoyer <maxim.cournoyer <at> gmail.com>
Date: Wed, 16 Aug 2023 14:41:55 -0400
Simon Tournier <zimon.toutoune <at> gmail.com> writes:
> Please note that if git.savannah.gnu.org is not reachable, then “guix
> time-machine” fails.
>
> Let start with the regular:
>
> $ guix describe
> Generation 26 Jul 12 2023 09:13:39 (current)
> guix 4a027d2
> repository URL: https://git.savannah.gnu.org/git/guix.git
> branch: master
> commit: 4a027d2b0ee68e39f21f6802a8cd1751d3065330
>
> $ guix time-machine --commit=4a027d2 -- describe
> Updating channel 'guix' from Git repository at 'https://git.savannah.gnu.org/git/guix.git'...
> substitute: updating substitutes from 'https://ci.guix.gnu.org'... 100.0%
> substitute: updating substitutes from 'https://bordeaux.guix.gnu.org'... 100.0%
> building /gnu/store/sg8ca36rlbh4il6jy8dk2gr33lxm4z8q-compute-guix-derivation.drv...
> Computing Guix derivation for 'x86_64-linux'... |
> substitute: updating substitutes from 'https://ci.guix.gnu.org'... 100.0%
> substitute: updating substitutes from 'https://bordeaux.guix.gnu.org'... 100.0%
> The following derivations will be built:
> [...]
> building profile with 1 package...
> guix 4a027d2
> repository URL: https://git.savannah.gnu.org/git/guix.git
> commit: 4a027d2b0ee68e39f21f6802a8cd1751d3065330
>
>
> So far, so good. Here all is cached and so on. Now, let make
> git.savannah.gnu.org unreachable by tweaking some stuff. Then,
>
> $ guix time-machine --commit=4a027d2 -- describe
> guix time-machine: error: Git error: failed to resolve address for git.savannah.gnu.org: Name or service not known
Interesting finding! I think it'd make sense to raise this issue
separately and discuss its resolution there, too keep things focused and
discoverable :-).
-------------------- End of forwarded message --------------------
The issue is introduced by commit
dce2cf311bc12dee4560329f53ccb53470d5793e in the procedure
reference-available?. The variable ’ref’ is the pair
(tag-or-commit . "123abc")
and fails with commit-id? in
(match ref
((or ('commit . commit)
('tag-or-commit . (? commit-id? commit)))
Therefore, reference-available? returns #f and the ’when’ branch is run
in update-cached-checkout.
;; Only fetch remote if it has not been cloned just before.
(when (and cache-exists?
(not (reference-available? repository ref)))
(remote-fetch (remote-lookup repository "origin")
#:fetch-options (make-default-fetch-options)))
Hence the network access required by remote-fetch.
Well, the heavy work to know if the reference is available or not in the
local checkout is done by ’resolve-reference’ in (guix git) doing all
the cases, and especially dealing with tag-or-commit:
(match ref
(('branch . branch)
(let ((oid (reference-target
(branch-lookup repository branch BRANCH-REMOTE))))
(object-lookup repository oid)))
(('commit . commit)
(let ((len (string-length commit)))
;; 'object-lookup-prefix' appeared in Guile-Git in Mar. 2018, so we
;; can't be sure it's available. Furthermore, 'string->oid' used to
;; read out-of-bounds when passed a string shorter than 40 chars,
;; which is why we delay calls to it below.
(if (< len 40)
(if (module-defined? (resolve-interface '(git object))
'object-lookup-prefix)
(object-lookup-prefix repository (string->oid commit) len)
(raise (condition
(&message
(message "long Git object ID is required")))))
(object-lookup repository (string->oid commit)))))
(('tag-or-commit . str)
(if (or (> (string-length str) 40)
(not (string-every char-set:hex-digit str)))
(resolve `(tag . ,str)) ;definitely a tag
(catch 'git-error
(lambda ()
(resolve `(tag . ,str)))
(lambda _
;; There's no such tag, so it must be a commit ID.
(resolve `(commit . ,str))))))
(('tag . tag)
(let ((oid (reference-name->oid repository
(string-append "refs/tags/" tag))))
(object-lookup repository oid))))
Instead of duplicating, I propose to reuse it. See the trivial first
patch. I think it fixes the annoyance.
Aside, please note that (guix channels) provide commit-or-tag. It
change nothing but I would find more consistent to have the same
nomenclature.
--8<---------------cut here---------------start------------->8---
(define (sexp->channel-news-entry entry)
"Return the <channel-news-entry> record corresponding to ENTRY, an sexp."
(define (pair language message)
(cons (symbol->string language) message))
(match entry
(('entry ((and (or 'commit 'tag) type) commit-or-tag)
('title ((? symbol? title-tags) (? string? titles)) ...)
('body ((? symbol? body-tags) (? string? bodies)) ...)
_ ...)
(channel-news-entry (and (eq? type 'commit) commit-or-tag)
(and (eq? type 'tag) commit-or-tag)
--8<---------------cut here---------------end--------------->8---
WDYT about tag-or-commit everywhere?
Last, as I pointed in a naive comment [1], I do not think that
guix/scripts/pull.scm or guix/time-machine.scm need to support both the
pair (commit . x) and (tag-or-commit . x) because the value ’ref’ is set
by the option. Hence the second patch.
1: https://yhetil.org/guix/87o7j7f2tb.fsf <at> gmail.com
Let me know if I am not missing something.
Cheers,
simon
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