bug#55415: emacs-minimal-28.1-builder: Unknown # object: "#<"

[Fredrik Salomonsson]

Hi,

Getting this error when I try and update my emacs profile after a recent
guix pull:

---8<---------------------------------------------------------------------------
substitute: updating substitutes from 'https://ci.guix.gnu.org'... 100.0%
substitute: updating substitutes from 'https://bordeaux.guix.gnu.org'... 100.0%
The following derivations will be built:
  /gnu/store/jwm349jkbx675lsgkgvlgvyyzg89v4vf-emacs-async-1.9.4.drv
  /gnu/store/ah6zl6vdns20nwdhahsspnnbxdr4j0bn-emacs-minimal-28.1.drv
building /gnu/store/ah6zl6vdns20nwdhahsspnnbxdr4j0bn-emacs-minimal-28.1.drv...
ice-9/read.scm:126:4: In procedure read-expr*:
/gnu/store/4i6avyj1sf50dmyg1242grbfacwgm4sa-emacs-minimal-28.1-builder:1:2852: 
Unknown # object: "#<"
builder for 
`/gnu/store/ah6zl6vdns20nwdhahsspnnbxdr4j0bn-emacs-minimal-28.1.drv' failed 
with exit code 1
build of /gnu/store/ah6zl6vdns20nwdhahsspnnbxdr4j0bn-emacs-minimal-28.1.drv 
failed
View build log at 
'/var/log/guix/drvs/ah/6zl6vdns20nwdhahsspnnbxdr4j0bn-emacs-minimal-28.1.drv.gz'.
cannot build derivation 
`/gnu/store/jwm349jkbx675lsgkgvlgvyyzg89v4vf-emacs-async-1.9.4.drv': 1 
dependencies couldn't be built
guix build: error: build of 
`/gnu/store/jwm349jkbx675lsgkgvlgvyyzg89v4vf-emacs-async-1.9.4.drv' failed
--------------------------------------------------------------------------->8---

I have narrowed it down to commit
64557bc695f074af3fcf1eeed8f6696921ef18c5

I have commented out my third party channels (flatwhatson and my own plt
channel) and it still fails.

Here is a repro:

guix describe --format=channels:

---8<---------------------------------------------------------------------------
(list (channel
        (name 'guix)
        (url "https://git.savannah.gnu.org/git/guix.git";)
        (branch #f)
        (commit
          "64557bc695f074af3fcf1eeed8f6696921ef18c5")
        (introduction
          (make-channel-introduction
            "9edb3f66fd807b096b48283debdcddccfea34bad"
            (openpgp-fingerprint
              "BBB0 2DDF 2CEA F6A8 0D1D  E643 A2A0 6DF2 A33A 54FA")))))
-------------------------------------------------------------------------->8---

Run:

guix pull --commit=64557bc695
guix build emacs-async

I'm on a foreign distro if that makes any difference.

Thanks.

-- 
s/Fred[re]+i[ck]+/Fredrik/g