From: ilmu <ilmu@rishi.is>
To: "Ludovic Courtès" <ludo@gnu.org>
Cc: "guix-devel@gnu.org" <guix-devel@gnu.org>
Subject: Re: Deep vs Shallow trace: Removing the tradeoff?
Date: Sun, 18 Apr 2021 05:51:09 +0000 [thread overview]
Message-ID: <orFr5kxfZN3anDAuCAC42DC3hw-DqwMkjvMheahbwguP62RlkHXsGdWtaGNNYiPkeOhENkv362TZMz8JGUDKfayx7-RzVlUNQ9COGZAnoWo=@rishi.is> (raw)
In-Reply-To: <87zgxxt0i3.fsf@gnu.org>
> What’s currently implemented is memoization: the hash (of the .drv and
> that of the output(s)) is computed over all the inputs.
>
> Since the output file name (the one passed to “./configure --prefix” &
> co.) appears in the build result 99% of the time, the content vary at
> least due to occurrences of the output file name.
>
> Thus, content comparison are not doable as is. What would help is
> content comparison modulo output file name(s).
>
> But again, “same hash as it did before” is a framing that doesn’t hold
> in a purely functional, stateless context.
Thank you for the clarification. Although, I must admit, I am not sure why the filename would change (except if it happens as a consequence of the hash being put in the filename).
I will need to spend the next few months actually reading the code and getting familiar with how things work "on the ground" before I can have anything useful to say. The reason I started this particular discussion was mostly to get a reality check whether the same methods apply in the build system context as in other authenticated datastructures (I don't see why not but I'm a layman, hence reality checks..)
In any case, glad to receive and answer. Keep up the good work! :)
Kind regards,
- Ilmu
prev parent reply other threads:[~2021-04-18 5:51 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-27 16:56 Deep vs Shallow trace: Removing the tradeoff? ilmu
2021-03-28 0:50 ` Julien Lepiller
2021-03-28 23:16 ` ilmu
2021-03-30 10:46 ` Ludovic Courtès
2021-03-30 20:20 ` Bengt Richter
2021-04-02 15:45 ` ilmu
2021-04-17 15:05 ` Ludovic Courtès
2021-04-18 5:51 ` ilmu [this message]
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