From mboxrd@z Thu Jan  1 00:00:00 1970
From: ludo@gnu.org (Ludovic =?utf-8?Q?Court=C3=A8s?=)
Subject: Re: emacs-dev: 'unpack' phase does not seem to preserve timestamps
Date: Wed, 23 May 2018 17:01:09 +0200
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In-Reply-To: <874lj6iaap.fsf@gmail.com> (Pierre Neidhardt's message of "Thu,
	17 May 2018 17:14:38 +0200")
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To: Pierre Neidhardt <ambrevar@gmail.com>
Cc: help-guix <help-guix@gnu.org>

Hello,

Pierre Neidhardt <ambrevar@gmail.com> skribis:

> Since all file timestamps are set to Epoch by 'unpack', the build phase
> tries to rebuild everything.
> And since the files unpacked to "source" are read-only, `make` fails to
> regenerate the files that go in "source".

Yes, that=E2=80=99s annoying, but that=E2=80=99s expected.  Perhaps the =E2=
=80=98unpack=E2=80=99
phase could automatically make the copy that it creates with
=E2=80=98copy-recursively=E2=80=99 writable?

> From the source, 'unpack' is supposed to preserve the timestamp:
>
> (define* (unpack #:key source #:allow-other-keys)
>   "Unpack SOURCE in the working directory, and change directory within the
> source.  When SOURCE is a directory, copy it in a sub-directory of the cu=
rrent
> working directory."
>   (if (file-is-directory? source)
>       (begin
>         (mkdir "source")
>         (chdir "source")
>
>         ;; Preserve timestamps (set to the Epoch) on the copied tree so t=
hat
>         ;; things work deterministically.
>         (copy-recursively source "."
>                           #:keep-mtime? #t)

It does preserve timestamps, but since SOURCE is in the store, its
timestamps are all set to the Epoch.

But that=E2=80=99s OK: Git doesn=E2=80=99t specify timestamps anyway.

Thanks,
Ludo=E2=80=99.