Hi!

I'd like to write a package definition whose source is different
depending on the system / arch it is built for.

I thought of writing something like this:

--8<---------------cut here---------------start------------->8---
(source (origin
         (method url-fetch)
         (uri
          (string-append "http://foo.bar/"
                         version "-" 
                         (match (or (%current-target-system)
                                    (%current-system))
                           ("i686-linux" "x86")
                           ("x86_64-linux" "x86_64"))
                         ".tgz"))
         (sha256
          (base32
           (match (or (%current-target-system)
                      (%current-system))
             ("x86_64-linux"
              "0y4qms4lm9xiix93g45337rx5nrp0y3gb0x0avyv7l9qrkk03zz8")
             ("i686-linux"
              "0yc8n6vpqyb6qhcv5kwvr3h21ya271fi930fvd98hlkg8cg5kwyf"))))))
--8<---------------cut here---------------end--------------->8---

My laptop is a x86_64-linux and the above definition always uses the
x86_64 source, even with

  guix build --system=i686-linux foo

In Nix, the following works:

--8<---------------cut here---------------start------------->8---
  src =
    if stdenv.hostPlatform.system == "x86_64-linux" then
      fetchurl {
        url = "http://foo.bar/...";
        sha256 = "e8ff01e6cc38d1b3fd56a083f5860737dbd2f319a39037528fb1a74a89ae9878";
      }
    else if stdenv.hostPlatform.system == "i686-linux" then
      fetchurl {
        url = "http://foo.bar/...";
        sha256 = "cef3591e436f528852db0e8c145d3842f920e0c89bcfb219c466797cb7b18879";
      }
    else throw "foo does not support platform ${stdenv.hostPlatform.system}";
--8<---------------cut here---------------end--------------->8---

Is this a Guix bug?

-- 
Pierre Neidhardt
https://ambrevar.xyz/