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bug#32245: Guix does not search sources locally by hash
From: |
Ludovic Courtès |
Subject: |
bug#32245: Guix does not search sources locally by hash |
Date: |
Mon, 23 Jul 2018 16:50:49 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) |
Björn Höfling <address@hidden> skribis:
> On Mon, 23 Jul 2018 10:41:14 +0200
> address@hidden (Ludovic Courtès) wrote:
>
>> Hi,
>>
>> Björn Höfling <address@hidden> skribis:
>>
>> > $> ./pre-inst-env guix build java-eclipse
>> > [..]
>> > @
>> > build-started
>> > /gnu/store/lqfw971srfifgql68ibdgh58vi4d8fq3-java-eclipse-oxygen-3a-linux-gtk-x86_64.tar.gz.drv
>> > -
>> > x86_64-linux
>> > /var/log/guix/drvs/lq//fw971srfifgql68ibdgh58vi4d8fq3-java-eclipse-oxygen-3a-linux-gtk-x86_64.tar.gz.drv.bz2
>>
>> [...]
>>
>> > But it does NOT search locally. Because I already have:
>> >
>> > guix
>> > hash
>> > /gnu/store/56h6snwcawpzk6rhcwgk442wsx6k86q2-eclipse-java-oxygen-3a-linux-gtk-x86_64.tar.gz
>> > 0m7y7jfm059w01x9j5b5qkinjjmhkyygpjabhjf19fg2smxmwcim
>>
>> It does, but the file name matters. In this case what you have is
>> “eclipse-java-…” but you’re trying to build “java-eclipse-…”.
>>
>> So you first need to add the file to the store under its expected
>> name. You can do that for instance with:
>>
>> guix download file://…/java-eclipse-…
>>
>> HTH!
>
> Not sure yet. I havent't tried it yet, but I'm sure your solution
> helps with the specific problem here. (Also updating the URL helps even
> better :-))
>
> What I feel strange here is:
>
> * When the file is already on the local disk, it has to match a certain
> file name criteria. Quite hard criteria.
> * But when asking outside repositories over the network, we just "take
> anything that has the hashsum".
>
> Is that wanted behaviour?
It’s not optimal, as you pointed out. But it’s not implemented in these
terms. The ‘add-to-store’ RPC returns a file name that’s a function of
the content and the file name. So the way ‘add-to-store’ works is:
1. compute store file name = g(content, filename)
(See ‘fixed-output-path’ in (guix store).)
2. if store file name exists, return it, else create it.
Since /var/guix/db/db.sqlite contains the content hash of each store
item, we could in theory perform a lookup by hash. To do that we’d need
to add a new RPC and use it in the correct places. It’d be a nice
addition.
Ludo’.