Re: Package definition hash calculation

[Zelphir Kaltstahl <zelphirkaltstahl@posteo.de>]

Hello Julien!

I did create the release tag on the latest commit, which was also the master 
branch. I thought there was some clever trick to get Guix to ignore the 
`guix.scm` file, when calculating the hash sum, but apparently that is not the 
case. I still wonder how I made the first version of the package though. I did 
not know about `git-checkout` as `source` method. Thanks for that!

I am unsure, whether my project must have a `guix.scm` file or not, to be a 
valid Guix package in the end, when I add it to (update the entry in) 
`gnu/packages/guile-xyz.scm`. Maybe a `guix.scm` in the project is not even needed.

Anyway, the idea makes sense to track the master using a checkout without a hash 
sum, so that I don't have the problem of the hash changing any longer. Just not 
sure it will work for updating the package in guix. I will try it.

There is no information about `git-checkout`: 
https://guix.gnu.org/manual/en/html_node/origin-Reference.html Is it elsewhere 
in the docs?

Best regards,
Zelphir

On 7/9/22 13:44, Julien Lepiller wrote:
> When you use guix download, or url-fetch, the hash is computed over the entire 
> file, whether it's a tarball that contains other files or whatever else 
> doesn't matter. You can't exclude files from inside the tarball. It's just the 
> checksum of the file.
>
> What you describes sounds like you're downloading a tarball that's generated 
> from your master instead of a particular commit. So everytime you push a 
> change to guix.scm, it's a new commit and a different tar.gz (different 
> checksum). So you're always chasing after the correct checksum, which won't work.
>
> So you can have a guix.scm in your repo, but it can't refer to a generated 
> tarball from master. Instead, you could make it refer to master and not have 
> to provide a hash like so:
>
> (source (git-checkout (url "https://…")))
>
> No more chasing afcer master :)
>
> On July 9, 2022 1:09:27 PM GMT+02:00, Zelphir Kaltstahl 
> <zelphirkaltstahl@posteo.de> wrote:
>
>     Hello Guix users!
>
>     I feel a bit stupid to ask about this topic again, however, to me it is not really clear, what I need to do, when calculating the hash of a package, so that I can write it in the package definition.
>
>     I have a project (https://notabug.org/ZelphirKaltstahl/guile-fslib),  which I have packaged before, but that was already a year ago or so, and I forgot the precise process involving the hashes.
>
>     I have the following questions:
>
>     (1) When I edit the `guix.scm` file and change the hash in there, make a tarball release on notabug, and then run `guix download <tarball of release>`, I get a new hash. If I edit the guix.scm file again and repeat the process, I get a new hash … endless loop of getting a new hash and changing the file accordingly. My guess is, that this is, because `guix download` does not exclude the `guix.scm` file. I would have to manually make a `tar.gz` and upload that as a release to notabug and then reference that. – Is this correct?
>
>     (2) I guess I should be using `guix hash --exclude-vcs --serializer=nar --format=??? .` instead, since my package definition makes use of the `git-fetch` method of fetching the package. I had totally forgotten about this, until I searched in old e-mails, reading old replies to previous questions I asked on this mailing list. I think it could be made clearer in the docs, which command to use in which case. However, now I am not sure which `--format=` I should use. I would guess `base32`, because in my package definition it says `(sha256 (base32 "..."))`. Is this correct? Or is the default fine?
>
>     (3) What is the recommended way to update a package's source code and then "in one go" calculate the hash, update the `guix.scm` and make a proper release, which only has the appropriate files in the tarball?
>
>     (4) Should a release tarball contain a `guix.scm` package definition? (My guess is not, since the hash in that file changes and that would change the tarball. Maybe I am overlooking things/magic though.)
>
>     I am feeling like I am stuck in what should be a simple process, because I still have some points that are unclear to me. I try updating my guide to packaging a pure Guile package when I learn new things, so that I can read up next time I want to make a release or a new package, but a few things are still missing or unclear.
>
>     Thank you for all your help!
>
>     Best regards,
>     Zelphir
>
>     -- repositories: https://notabug.org/ZelphirKaltstahl
>
-- 
repositories:https://notabug.org/ZelphirKaltstahl